Essences of clinical medicine.

Cardiology / 循環器科

Ischemic Heart Disease and Heart Failure / 虚血性心疾患・心不全

Effort Angina / 労作性狭心症

• Overview
  • Transient myocardial ischemia due to coronary artery stenosis (from atherosclerosis) and increased oxygen demand (during exertion)
  • Risk factors: Hypertension, DM, dyslipidemia, smoking, aging
• Presentation
  • Chest tightness/pressure during exertion (lasting 3-5 minutes): Temporary myocardial ischemia, rapid relief with nitroglycerin
• Examination
  • [ECG] ST depression (during attack or exercise stress): Ischemia
  • [Echocardiography] Wall motion abnormality: Ischemia
  • [Blood] No elevation in cardiac biomarkers: Excludes myocardial necrosis
  • [Myocardial perfusion SPECT] Reduced uptake during stress, improved at rest: Reversible ischemia
• Management
  • Nitroglycerin (sublingual): Rapid relief of acute attacks (relax coronary artery)
  • β-blockers, calcium channel blockers: Prevent attacks (decrease oxygen demand)
  • Antiplatelet drugs, statins: Prevent thrombosis, improve atherosclerosis
  • Percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG): For severe cases
  • Lifestyle modifications

Vasospastic Angina / 冠攣縮性狭心症

• Overview
  • Transient myocardial ischemia caused by coronary artery spasm
  • Risk factors: Smoking, hypertension, DM, dyslipidemia
• Presentation
  • Chest tightness/pressure at night to early morning or at rest (lasting several to 15 minutes): Coronary artery spasm, triggered by hyperventilation, alcohol, or early morning exercise
• Examination
  • [ECG] ST elevation or depression (during attack): Ischemia due to spasm
  • [Blood] No elevation in cardiac biomarkers: Excludes myocardial infarction
  • [Coronary angiography] Hyperventilation or drug-induced spasm: Confirms diagnosis
• Management
  • Nitroglycerin (sublingual): Rapid relief of acute attacks (relax coronary artery)
  • Calcium channel blockers, nitrates: Prevent attacks (relax coronary artery)
  • Lifestyle modifications

Acute Coronary Syndrome / 急性冠症候群

• Overview
  • Myocardial ischemia and necrosis due to rapid narrowing or obstruction of coronary artery by thrombosis formation, encompasses unstable angina, acute myocardial infarction, and sudden cardiac death due to ischemia
  • Classified as non-ST elevation ACS (NSTE-ACS) and ST elevation myocardial infarction (STEMI)
  • Risk factors: Hypertension, DM, dyslipidemia, smoking, aging
• Presentation
  • Chest pain at rest or during exertion (lasting several to >15 minutes): Acute myocardial ischemia
• Examination
  • [ECG] ST elevation (or depression for NSTE-ACS), hyperacute T, abnoraml Q: Infarction or ischemia
  • [Blood] Elevated cardiac troponin: Confirms myocardial injury
  • [Echocardiography]: Abnormal wall motions
• Management
  • [Initial treatment] Morphine, oxygen, nitroglycerin, aspirin: Stabilize general condition
  • [Reperfusion therapy] Percutaneous coronary intervention (PCI), thrombolysis (t-PA), coronary artery bypass grafting (CABG): Reopen obstructed coronary artery (first choice: PCI)
  • [Antiplatelet drugs] Aspirin, clopidogrel, prasugrel: Prevent thrombosis
  • [Anti-anginal drugs] β-blockers, nitrates, calcium channel blockers: Reduce oxygen demant and relax coronary artery
  • [Anti-hypertensive drugs] ACE inhibitors, ARBs, MRAs: Reduce afterload
  • [Anti-hyperlipidemic drugs] Statins: Prevent recurrence
  • [Complications management] Arrhythmias, heart failure, stroke, cardiac rehabilitation

Heart Failure / 心不全

• Overview
  • Cardiac pump dysfunction leading to pulmonary and systemic congestion
  • Causes: Ischemic heart disease, valvular heart disease, cardiomyopathy, hypertension
• Presentation
  • Dyspnea, tachypnea, orthopnea, paroxysmal nocturnal dyspnea: Left-sided heart failure (pulmonary congestion)
  • Leg edema, jugular vein distension: Right-sided heart failure (systemic congestion)
• Examination
  • [Auscultation] Coarse crackles, S3 or S4 gallop: Pulmonary congestion, ventricular dysfunction
  • [Chest X-ray] Cardiomegaly, pulmonary vascular markings, butterfly shadow, Kerley’s lines, pleural effusion: Cardiac enlargement and congestion
  • [Blood] BNP↑, NT-proBNP↑: Sensitive markers of heart failure
  • [Echocardiography] Systolic dysfunction, diastolic dysfunction: Cardiac function assessment
• Management
  • Diuretics, vasodilators: Improve hemodynamics and symptoms
  • ACE inhibitors, ARBs, ARNI, MRAs, β-blockers, ivabradine: Cardioprotective effects
  • ICD, CRT, MitraClip, IABP, ECMO, IMPELLA, VAD: Cardiac and circulatory support for severe cases
  • Heart transplantation: For end-stage heart failure
  • Disease management: Address underlying causes

Arrhythmia / 不整脈

Atrial Premature Contraction / 心房期外収縮

• Overview
  • Premature excitation from atria earlier than sinus node firing
• Presentation
  • Asymptomatic, palpitations, chest discomfort: Mostly asymptomatic
• Examination
  • [ECG] Early P wave: Premature atrial depolarization
• Management
  • Observation: For asymptomatic cases
  • β-blockers , Na channel blockers: For symptomatic cases

Paroxysmal Supraventricular Tachycardia / 発作性上室頻拍

• Overview
  • Supraventricular tachycardia due to reentry involving AV node (AVNRT) or accessory pathway (AVRT)
• Presentation
  • Palpitations (sudden onset and termination): Reentry mechanism
  • Dizziness, syncope (in severe cases): Due to reduced cardiac output
• Examination
  • [ECG] Regular narrow QRS complexes at 120-220 bpm: Supraventricular origin of tachycardia
• Management
  • Vagal maneuvers, ATP, calcium channel blockers: For stable hemodynamics
  • Cardioversion, overdrive pacing: For unstable hemodynamics
  • Catheter ablation: Curative treatment

Wolff-Parkinson-White Syndrome / WPW症候群

• Overview
  • Presence of accessory pathway directly connecting atria and ventricles, can cause AVRT or AF resembling VT
• Presentation
  • Asymptomatic: Mostly
  • Palpitations, syncope: During tachycardia episodes
• Examination
  • [ECG] Delta wave, short PQ interval, wide QRS complex: Ventricular pre-excitation through accessory pathway
  • [ECG] AVRT or AF resembling VT (during episodes): Reentry or direct connection
• Management
  • Observation: For asymptomatic cases
  • Vagal maneuvers, ATP, Ca channel blockers: For AVRT
  • Na channel blockers: For AF resembling VT (digitalis and Ca channel blockers contraindicated)
  • Cardioversion: For hemodynamically unstable AVRT or AF
  • Catheter ablation: Curative treatment

Atrial Flutter / 心房粗動

• Overview
  • Regular reentrant circuit in atria with consistent conduction to ventricles
• Presentation
  • Palpitations, dyspnea: Due to rapid heart rate
• Examination
  • [ECG] Regular RR intervals, narrow QRS complexes, regular flutter waves (~300/min): Regular tachycardia with consistent AV conduction ratio
• Management
  • Na channel blockers, K channel blockers, Ca channel blockers, cardioversion: Termination of episodes
  • Catheter ablation: Prevention of recurrence
  • Anticoagulation: For thromboembolic prevention
  • Upstream therapy: Treatment of underlying diseases

Atrial Fibrillation / 心房細動

• Overview
  • Rapid and disorganized electrical activity in atria leading to irregular ventricular conduction
  • Common in elderly, hypertension, valvular disease, heart failure, ischemic heart disease, hyperthyroidism
  • High risk of thromboembolism due to left atrial thrombus formation
• Presentation
  • Palpitations, irregular pulse: Due to irregular ventricular conduction
• Examination
  • [ECG] Irregular RR intervals, narrow QRS complexes, absence of P waves with fine baseline oscillations: Rapid atrial activation with irregular conduction to ventricles
• Management
  • Anticoagulation (warfarin, DOAC): Thromboembolism prevention
  • β-blockers, Ca channel blockers, digitalis: Rate control
  • Na channel blockers, K channel blockers, cardioversion: Rhythm control
  • Catheter ablation: Prevention of recurrence
  • Upstream therapy: Treatment of underlying diseases

Ventricular Premature Contraction / 心室期外収縮

• Overview
  • Premature ectopic excitation from ventricles, seen in patients with underlying heart diseases
• Presentation
  • Asymptomatic, palpitations, chest discomfort
• Examination
  • [ECG] Wide QRS complex without preceding P wave: Premature ventricular depolarization
• Management
  • Observation: For asymptomatic cases without risk factors
  • Na channel blockers, K channel blockers, β-blockers: For symptomatic cases or risk of VT/VF (myocardial infarction)

Ventricular Tachycardia / 心室頻拍

• Overview
  • Consecutive VPCs causing tachycardia, dangerous arrhythmia with risk of pulselessness and VF
• Presentation
  • Palpitations, shortness of breath: Due to rapid heart rate
  • Dizziness, syncope, loss of consciousness: Due to reduced cardiac output
• Examination
  • [ECG] Wide QRS complexes occurring regularly: Regular ventricular tachycardia
• Management
  • Amiodarone, nifekalant, procainamide: Acute termination (hemodynamically stable)
  • Cardioversion, electrical defibrillation: Acute termination (hemodynamically unstable)
  • Amiodarone, sotalol, bepridil, catheter ablation: Prevention of recurrence (normal cardiac function)
  • Implantable cardioverter-defibrillator (ICD): Prevention of recurrence (reduced cardiac function)

Ventricular Fibrillation / 心室細動

• Overview
  • Completely disorganized ventricular excitation resulting in zero cardiac output, rapidly fatal without immediate treatment
  • Common in: STEMI, cardiomyopathy, Brugada syndrome, long QT syndrome, hypoxemia, hypothermia
• Presentation
  • Dizziness followed by immediate syncope, absence of pulse: Sudden loss of cardiac output
• Examination
  • [ECG] Completely irregular waves with variable amplitude and frequency: Chaotic ventricular activity
• Management
  • Immediate electrical defibrillation: First-line treatment
  • CPR 2 minutes, IV adrenaline, defibrillation: If above unsuccessful
  • CPR 2 minutes, IV nifekalant or amiodarone, defibrillation: If above unsuccessful
  • CPR 2 minutes, IV β-blockers, left stellate ganglion block: If above unsuccessful
  • Treatment of underlying disease: If defibrillation successful

Sick Sinus Syndrome / 洞不全症候群

• Overview
  • Dysfunction of sinoatrial node or surrounding tissue, leading to sinus bradycardia, sinoatrial block, or sinus arrest
• Presentation
  • Dizziness, lightheadedness, syncope: Cerebral hypoperfusion due to bradycardia
  • Fatigue, shortness of breath: Heart failure symptoms
• Examination
  • [ECG] Sinus bradycardia (HR < 50 bpm), sinus arrest (absence of P waves): Dysfunction of sinoatrial node
• Management
  • Observation: For asymptomatic cases
  • Pacemaker implantation: For persistent symptomatic bradycardia
  • Atropine, isoproterenol, theophylline, cilostazol: For cases where pacemaker is not suitable

Atrioventricular Block / 房室ブロック

• Overview
  • Delayed or interrupted conduction from atria to ventricles at AV node or His bundle
• Presentation
  • Syncope, heart failure: Due to decreased cardiac output
• Examination
  • [ECG] Prolonged PQ intervals: 1st degree AV block
  • [ECG] Progressive lengthing of PQ intervals with subsequent QRS drop: Mobitz I 2nd degree AV block
  • [ECG] Regular PQ intervals with random QRS drop: Mobitz II 2nd degree AV block
  • [ECG] P and QRS independently at regular intervals: 3rd degree AV block
  • [Auscultation] Cannon sound: Loud S1 every few beats (3rd degree AV block)
• Management
  • Observation: For 1st degree and Mobitz I 2nd degree AV block
  • Pacemaker implantation: For Mobitz II 2nd degree and 3rd degree AV block
  • Atropine, isoproterenol: Bridge therapy before pacemaker implantation

Bundle Branch Block / 脚ブロック

• Overview
  • Impaired conduction in right or left bundle branch due to myocardial ischemia or degeneration
• Presentation
  • Asymptomatic
• Examination
  • [ECG] Wide QRS, rSR’ in V1, wide S in V6: Right bundle branch block
  • [ECG] Wide QRS, QS or rS in V1, absent septal Q and notched QRS in V6: Left bundle branch block
• Management
  • Observation: Mostly
  • Cardiac resynchronization therapy (CRT): For some left bundle branch block

Brugada Syndrome / Brugada症候群

• Overview
  • Genetic disorder causing ventricular fibrillation during parasympathetic dominance
  • More common in young to middle-aged men, often associated with family history of sudden death
• Presentation
  • Recurrent syncope, loss of consciousness: Due to VF episodes
  • Sudden cardiac death: Especially during sleep or rest after meals
• Examination
  • [ECG] Right bundle branch block pattern, characteristic ST elevation: Diagnostic feature
• Management
  • Implantable cardioverter defibrillator (ICD): Only effective prevention for sudden death
  • Pharmacological therapy, catheter ablation: Considered in some cases

Long QT Syndrome / QT延長症候群

• Overview
  • Prolongation of myocardial action potential leading to extended QT interval, can cause torsades de pointes (a type of polymorphic VT)
• Presentation
  • Recurrent syncope: Due to TdP episodes
  • Sudden cardiac death: In severe cases
• Examination
  • [ECG] Corrected QT interval > 0.48 seconds: Diagnostic feature
• Management
  • Beta-blockers, temporary pacing: For congenital LQTS
  • Remove underlying cause: For acquired LQTS
  • Magnesium sulfate: During TdP episodes

Endocardium and Valvular Disease / 心内膜・弁膜疾患

Mitral Stenosis / 僧帽弁狭窄症

• Overview
  • Narrowing of mitral valve, impeding blood flow from left atrium to left ventricle
  • Common in women over 40-50 years, often with history of rheumatic fever
• Presentation
  • Dyspnea on exertion, palpitations, irregular pulse: Due to pulmonary congestion and atrial fibrillation
  • Embolism: Thrombus formation in left atrium
• Examination
  • [Auscultation] Accentuated S1, opening snap, diastolic rumble, presystolic murmur: Mitral valve stenosis
  • [ECG] Left atrial enlargement, atrial fibrillation: Increase left atrium pressure
  • [Chest X-ray] Prominent left 3rd arc: Enlarged left atrium
  • [Echocardiography] Reduced valve area, dome-shaped anterior mitral leaflet: Confirms diagnosis
• Management
  • Symptomatic treatment: For heart failure
  • Anticoagulation: For patients with AF
  • Percutaneous mitral commissurotomy (PTMC): Catheter-based valve opening
  • Open mitral commissurotomy (OMC) or mitral valve replacement (MVR): Surgical options

Mitral Regurgitation / 僧帽弁閉鎖不全症

• Overview
  • Backflow of blood from left ventricle to left atrium during systole
  • Common causes: mitral valve prolapse, ischemic heart disease
• Presentation
  • Dyspnea on exertion, palpitations, fatigue, paroxysmal nocturnal dyspnea, orthopnea: Left heart failure symptoms
• Examination
  • [Auscultation] Holosystolic murmur at apex, diminished S1, S3: Mitral valve regurgitation
  • [ECG] Left atrial enlargement, left ventricular hypertrophy, atrial fibrillation: Increased volume load
  • [Chest X-ray] Prominent left 3rd and 4th arcs: Left atrial and ventricular enlargement
  • [Echocardiography] Valve abnormalities, left heart enlargement, regurgitation: Confirms diagnosis
• Management
  • Symptomatic treatment: For heart failure
  • Mitral valve repair or replacement (MVR): Surgical options

Mitral Valve Prolapse / 僧帽弁逸脱症

• Overview
  • Syndrome characterized by prolapse of mitral valve leaflets into left atrium during systole
  • Often idiopathic, can be associated with Marfan syndrome
• Presentation
  • Asymptomatic, chest pain, dizziness: Mild cases
  • Heart failure symptoms: Severe mitral regurgitation
• Examination
  • [Auscultation] Mid-systolic click or Holosystolic murmur: Mitral valve prolapse or regurgitation
  • [Echocardiography] Prolapse of mitral valve leaflets during systole: Confirms diagnosis
• Management
  • β blockers: For chest pain and dizziness

Aortic Stenosis / 大動脈弁狭窄症

• Overview
  • Narrowing of aortic valve, impeding blood flow from left ventricle to aorta
  • Causes: Degeneration due to aging, abnormal number of valves
• Presentation
  • Dyspnea, angina: Left heart failure, myocardial ischemia due to ventricular hypertrophy
  • Syncope, dizziness, slow and weak pulse, hypotension: Reduced cardiac output
• Examination
  • [Auscultation] Ejection click, systolic ejection murmur, diminished and paradoxical splitting of S2: Aortic valve stenosis
  • [ECG] Left ventricular hypertrophy
  • [Echocardiography] Restricted valve opening, reduced valve area, increased transvalvular gradient: Confirms diagnosis
• Management
  • Aortic valve replacement (AVR): Surgical option
  • Transcatheter aortic valve implantation (TAVI): Less invasive option

Aortic Regurgitation / 大動脈弁閉鎖不全症

• Overview
  • Backflow of blood from aorta to left ventricle during diastole
  • Causes left ventricular volume and pressure overload, leading to LV enlargement and hypertrophy
  • Can be compensated for long periods, but poor prognosis once heart failure develops
• Presentation
  • Palpitations: Increased stroke volume
  • Dyspnea, angina: Pulmonary congestion, decreased diastolic aortic pressure
  • Strong and fast pulse, capillary pulsations of fingernail bed (Quincke’s sign): Increased pulse pressure
• Examination
  • [Auscultation] Diastolic decrescendo murmur, systolic ejection murmur, Austin-Flint murmur: Aortic valve regurgitation, relative AS, functional MS
  • [Chest X-ray] Prominent left 4th arc: Left ventricular enlargement
  • [ECG] Left ventricular hypertrophy
  • [Echocardiography] Valve abnormalities, left ventricular enlargement, regurgitation, fluttering of mitral valve: Confirms diagnosis
• Management
  • Aortic valve replacement (AVR) or aortic valvuloplasty (AVP): Surgical option

Tricuspid Stenosis / 三尖弁狭窄症

• Overview
  • Narrowing of tricuspid valve, impeding blood flow from right atrium to right ventricle
  • Mostly due to rheumatic fever
• Presentation
  • Asymptomatic
  • Right heart failure symptoms: In advanced cases
• Examination
  • [Auscultation] Diastolic rumble: Tricuspid valve stenosis
  • [Echocardiography] Restricted tricuspid valve, increased transvalvular gradient: Confirms diagnosis
• Management
  • Symptomatic treatment: For heart failure
  • Tricuspid valve replacement: Surgical options

Tricuspid Regurgitation / 三尖弁閉鎖不全症

• Overview
  • Backflow of blood from right ventricle to right atrium during systole
  • Common causes: Pulmonary hypertension due to left valvular heart disease
• Presentation
  • Asymptomatic
  • Right heart failure symptoms: In advanced cases
• Examination
  • [Auscultation] Holosystolic murmur: Tricuspid valve regurgitation
  • [Echocardiography] Valve abnormalities, regurgitation: Confirms diagnosis
• Management
  • Symptomatic treatment: For heart failure
  • Tricuspid valve repair or replacement: Surgical options

Infective Endocarditis / 感染性心内膜炎

• Overview
  • Systemic septic disease with vegetation formation on heart valves or endocardium due to bacterial infection
  • Common cause: Dental intervention, with underlying congenital heart disease or valvular heart disease
• Presentation
  • Fever, joint pain, muscle pain: Systemic infection
  • Petechiae, splinter hemorrhages, Osler nodes, Janeway lesions, Roth spots: Peripheral embolism
  • Stroke, renal infarction, splenic infarction: Systemic embolism
  • Congestive heart failure: Valve destruction, regurgitation, or chordae tendineae rupture
• Examination
  • [Auscultation] Heart murmur: Valvular damage
  • [Blood] WBC↑, ESR↑, CRP↑, γ-globulin↑, fibrinogen↑: Inflammatory response
  • [Blood culture] Pathogen detection: Confirms causative microorganism
  • [Echocardiography] Vegetation: Confirms cardiac involvement
• Management
  • High-dose, long-term intravenous antibiotics: Based on causative microorganism
  • Surgical intervention: If antibiotics ineffective

Cardiac Myxoma / 心臓粘液腫

• Overview
  • Most common primary cardiac tumor, mostly occur in the left atrium
• Presentation
  • Fatigue, weight loss, fever, joint pain: Systemic effects due to IL-6 secreted by tumor
• Examination
  • [Auscultation] Variable diastolic murmur with position changes, tumor plop: Tumor movement mimicking mitral stenosis
  • [Blood] ESR↑, WBC↑, CRP↑, γ-globulin↑: Inflammation due to IL-6 secreted by tumor
  • [Echocardiography] Mass in atrium: Confirms diagnosis
• Management
  • Surgical resection: Prevents potentially fatal embolization

Myocardium Disease / 心筋疾患

Dilated Cardiomyopathy / 拡張型心筋症

• Overview
  • Degenerative myocardial disease with left ventricular dilation and reduced contractility
  • More common in males aged 40-70, about 20-30% are familial
• Presentation
  • Palpitations, dyspnea, pulsus alternans, edema: Chronic progressive heart failure
• Examination
  • [Auscultation] S3 or S4 (gallop rhythm), systolic murmur: Heart failure, ventricular dilation leading to mitral regurgitation
  • [ECG] Left ventricular high voltage, wide QRS: Left ventricular hypertrophy
  • [Chest X-ray] Cardiomegaly: Heart failure
  • [Echocardiography, MRI] Dilated left ventricle, diffuse hypokinesis: Left ventricular dilation
  • [Cardiac catheterization] LVEDP↑, PAWP↑: Left heart failure
• Management
  • Lifestyle modifications (restrict water and salt), medication (β-blockers, ACE inhibitors, ARBs, MRAs): For heart failure
  • Cardiac resynchronization therapy (CRT), ventricular assist devices (VAD), heart transplantation: For severe heart failure
  • Anticoagulation: For thromboembolism prevention
  • Antiarrhythmic drugs, implantable cardioverter-defibrillator (ICD), pacemaker: For arrhythmia management

Hypertrophic Cardiomyopathy / 肥大型心筋症

• Overview
  • Degenerative myocardial disease with asymmetric ventricular hypertrophy, with high risk of sudden death
  • 50% familial (autosomal dominant, mutation of sarcomere protein gene)
• Presentation
  • Chest pain, dyspnea, palpitations: Due to increased oxygen demand, pulmonary congestion, and arrhythmia
  • Dizziness, syncope: Due to left ventricular outflow tract obstruction or arrhythmia
• Examination
  • [Auscultation] S4, S3, increased apical impulse: Ventricular diastolic dysfunction
  • [ECG] Left ventricular high voltage, ST depression, negative T waves: Left ventricular hypertrophy, relative ischemia
  • [Chest X-ray] Normal or mild cardiomegaly, upper lung field congestion: Pulmonary congestion
  • [Echocardiography, MRI] Asymmetric left ventricular wall hypertrophy (thickness ≥15 mm), diastolic dysfunction: Left ventricular hypertrophy
  • [Cardiac catheterization] LVEDP↑: Diastolic dysfunction
• Management
  • Lifestyle modifications (Avoid strenuous exercise), implantable cardioverter-defibrillator (ICD): Prevent sudden death
  • Medications (β-blockers, CCBs, diuretics, ACE inhibitors, ARBs): For heart failure
  • Antiarrhythmic drugs, anticoagulants: For arrhythmia management

Hypertrophic Obstructive Cardiomyopathy / 閉塞性肥大型心筋症

• Overview
  • Subset of HCM with left ventricular outflow tract obstruction (about 25% of HCM cases)
• Presentation
  • Symptoms of HCM
  • Bifid pulse: Due to dynamic obstruction
• Examination
  • [Auscultation] Ejection systolic murmur: Outflow obstruction
  • [Echocardiography] Systolic anterior motion of mitral valve: Due to increased outflow speed and Venturi phenomenon
  • [Cardiac catheterization] Brockenbrough phenomenon: Increased LV-aorta systolic pressure gradient after premature ventricular contraction
• Management
  • Treatmnents of HCM
  • Medications (β-blockers, CCBs, antiarrhythmics): Decrease LV-aorta systolic pressure gradient
  • Surgical myectomy, pacemaker implantation, percutaneous transluminal septal myocardial ablation (PTSMA): For refractory cases

Restrictive Cardiomyopathy / 拘束型心筋症

• Overview
  • Characterized by reduced left ventricular compliance and diastolic dysfunction
• Presentation
  • Generalized edema, pulmonary congestion, pleural effusion: Heart failure symptoms
• Examination
  • [Cardiac catheterization] Dip and plateau pattern in ventricular pressure curve: Diastolic restriction
• Management
  • Symptom management (diuretics)

Cardiac Sarcoidosis / 心臓サルコイドーシス

• Overview
  • Part of systemic sarcoidosis, forming non-caseating epithelioid granulomas in multiple organs
• Presentation
  • Complete atrioventricular block, ventricular arrhythmias: Damage to conduction pathways and cardiac muscles
• Examination
  • [Ga scintigraphy, PET] Focal uptake in heart: Inflammation
• Management
  • Corticosteroid: Control inflammation

Cardiac Amyloidosis / 心アミロイドーシス

• Overview
  • Systemic syndrome with amyloid protein deposition in various organs (AL amyloidosis or ATTR amyloidosis)
• Presentation
  • Cardiac hypertrophy, diastolic dysfunction: Deposition of amyloid protein
• Examination
  • [ECG] Low voltage, conduction disorders: Damage to conduction pathways
  • [Echocardiography] Cardiac hypertrophy, diastolic dysfunction: Deposition of amyloid protein
  • [Cardiac biopsy] Amyloid deposition in myocardium: Confirms diagnosis
• Management
  • Symptomatic treatment: For heart failure and arrhythmias

Acute Myocarditis / 急性心筋炎

• Overview
  • Acute myocardial necrosis and dysfunction due to infection (mostly virus) or idiopathic, may cause of sudden death but good prognosis if overcome acute phase
• Presentation
  • Flu-like symptoms, gastrointestinal symptoms: Prodromal phase of infection
  • Heart failure symptoms, chest pain, fever: Acute cardiac inflammation
• Examination
  • [Auscultation] S3, crackles: Heart failure signs
  • [ECG] ST-T changes, arrhythmia: Myocardial injury and conduction disturbances
  • [Echocardiography] Diffuse wall thickening, hypokinesis, small cardiac chambers, pericardial effusion: Myocardial inflammation and dysfunction
  • [Blood] Troponin T↑, CK-MB↑, AST↑, LDH↑, CRP↑: Myocardial injury and inflammation
  • [Endomyocardial biopsy] Inflammatory cell infiltration, myocyte necrosis, interstitial edema: Confirms diagnosis
• Management
  • Bed rest, hospitalization: Supportive care
  • Diuretics, catecholamines, IABP, ECMO: For heart failure and cardiogenic shock
  • Pacemaker, defibrillation: For arrhythmia

Pericardium Disease / 心膜疾患

Acute Pericarditis / 急性心膜炎

• Overview
  • Acute inflammation of the pericardium, mostly idiopathic (90%) or viral, generally good prognosis
• Presentation
  • Chest pain worsening in supine position and during inspiration: Pericardial irritation
  • Fever: Inflammatory response
• Examination
  • [Auscultation] Pericardial friction rub: Inflamed pericardial surfaces rubbing together
  • [ECG] Diffuse concave ST elevation: Pericardial inflammation
  • [Blood] WBC↑, ESR↑, CRP↑: Inflammatory response
  • [Echocardiography] Small pericardial effusion: May be present
  • [Chest X-ray] Usually normal: Distinguishes from pleuritis
• Management
  • Symptomatic treatment (NSAIDs): Often self-resolving
  • Treat primary cause: If secondary to underlying disease

Cardiac Tamponade / 心タンポナーデ

• Overview
  • Life-threatening condition where pericardial fluid accumulation impairs cardiac filling
  • Causes include aortic dissection, cardiac rupture after MI, trauma, malignancies invading pericardium
• Presentation
  • Hypotension, jugular vein distension, muffled heart sounds: Decreased cardiac output, increased venous pressure, pericardial fluid accumulation
  • Hepatomegaly, ascites, leg edema: Right heart failure signs
  • Narrow pulse pressure, tachycardia, pulsus paradoxus (systolic BP drop during inspiration): Decreased cardiac output, exaggerated when increased venous return compress left ventricle
• Examination
  • [Chest X-ray] Enlarged flask-shaped cardiac silhouette: Pericardial effusion
  • [Echocardiography] Echo-free space in pericardium, ventricular free wall collapse: Confirmatory findings
• Management
  • Pericardiocentesis: Definitive treatment to drain fluid
  • Treat underlying cause

Constrictive Pericarditis / 収縮性心膜炎

• Overview
  • Chronic inflammation causing fibrotic thickening and calcification of pericardium, impairing cardiac filling
  • Causes include idiopathic, tuberculosis, viral, post-radiation, post-cardiac surgery
• Presentation
  • Dyspnea on exertion, fatigue: Decreased cardiac output
  • Jugular vein distension (exaggerated during inspiration = Kussmaul’s sign), ascites, edema, hepatomegaly, congestive cirrhosis: Right heart failure signs
• Examination
  • [Auscultation] Pericardial knock: Abrupt cessation of ventricular filling
  • [ECG] Low voltage, nonspecific ST-T changes: Thickening of pericardium
  • [Echocardiography, Chest X-ray, CT, MRI] Thickened or calcified pericardium: Thickening of pericardium
  • [Cardiac catheterization] M or W-shaped RAP curve, RVP dip and plateau pattern: Impaired ventricular filling lead to increased pressure of RA, rapid filling and termination of RV
• Management
  • Pericardiectomy: Definitive treatment

Congenital Heart Disease / 先天性心疾患

Atrial Septal Defect / 心房中隔欠損症

• Overview
  • Congenital defect in atrial septum causing left-to-right shunt
• Presentation
  • Asymptomatic (childhood): Left-to-right shunt compensated
  • Dyspnea on exertion, fatigue (adolescence/adulthood): Right heart volume overload
• Examination
  • [Auscultation] Fixed splitting of S2, systolic ejection murmur, accentuated S1, tricuspid diastolic rumble: Relative pulmonary stenosis and tricuspid stenosis due to right atrial volume overload
  • [ECG] Right axis deviation, incomplete right bundle branch block, right ventricular hypertrophy, atrial fibrillation: Right heart strain
  • [Echocardiography] Left atrium to right atrium shunt: Confirms diagnosis
  • [Cardiac catheterization] O2 step-up in right atrium: Quantifies shunt
• Management
  • Observation: For mild cases (pulmonary-to-systemic flow ratio <1.5)
  • Surgical or catheter-based closure: For significant shunts (ratio >1.5)

Ventricular Septal Defect / 心室中隔欠損症

• Overview
  • Congenital defect in ventricular septum causing left-to-right shunt
• Presentation
  • Asymptomatic: Left-to-right shunt compensated (small VSD)
  • Tachypnea, feeding difficulties, poor weight gain, sweating: Heart failure symptoms (large VSD)
• Examination
  • [Auscultation] Holosystolic murmur, palpable thrill: Shunt through defect (small VSD)
  • [Auscultation] Accentuated S2, diastolic rumble: Pulmonary hypertension, relative mitral stenosis (large VSD)
  • [ECG] Biventricular hypertrophy, left atrial overload: Pulmonary hypertension (large VSD)
  • [Chest X-ray] Marked ventricular and atrial enlargement, prominent pulmonary artery, increased pulmonary vascularity: Left-to-right shunt (large VSD)
  • [Echocardiography, left ventriculography] Left ventricle to right ventricle shunt: Confirms diagnosis
  • [Cardiac catheterization] O2 step-up in right atrium to ventricle: Quantifies shunt
• Management
  • Observation: Many small defects close spontaneously
  • Diuretics, surgical closure: For large VSD

Atrioventricular Septal Defect / 房室中隔欠損症

• Overview
  • Developmental defect of atrioventricular septum, classified into incomplete and complete type based on existence of VSD
  • Associated with Down syndrome
• Presentation
  • Asymptomatic, dyspnea: Heart failure symptoms
• Examination
  • [Auscultation] Systolic regurgitant murmur, systolic ejection murmur, diastolic rumble, fixed S2 splitting: MR + ASD (imcomplete AVSD)
  • [Auscultation] Systolic regurgitant murmur, diastolic rumble, accentuated S2: MR + VSD (complete AVSD)
  • [ECG] Left axis deviation, incomplete right bundle branch block, prolonged PQ interval, right ventricular hypertrophy: Conduction abnormalities and right heart strain
  • [Chest X-ray] Cardiomegaly, increased pulmonary vascularity: Volume overload and increased pulmonary flow
  • [Echocardiography] ASD, VSD (in complete type), left-to-right shunt, valve abnormalities: Confirms diagnosis
  • [Cardiac catheterization] O2 step-up in right heart chambers: Quantifies shunt
  • [Left ventriculography] Goose-neck sign: Characteristic appearance of AVSD
• Management
  • Surgical closure of defects, mitral valve repair: For incomplete and complete AVSD

Patent Ductus Arteriosus / 動脈管開存症

• Overview
  • Persistence of fetal ductus arteriosus between aortic isthmus and pulmonary artery
  • Associated with congenital rubella syndrome
• Presentation
  • Asymptomatic: In mild cases
  • Widened pulse pressure, bounding pulse, Quincke’s sign: Increased systolic and decreased diastolic pressures
• Examination
  • [Auscultation] Continuous machinery murmur: Aorta-to-pulmonary artery shunt
  • [ECG] Left ventricular hypertrophy: Increased pulmonary flow
  • [Chest X-ray] Prominent left 1st/2nd/4th arches, increased pulmonary vascularity: Volume overload and increased pulmonary flow
  • [Echocardiography, aortography] Aorta-to-pulmonary artery shunt: Confirms diagnosis
  • [Cardiac catheterization] O2 step-up in pulmonary artery: Quantifies shunt
• Management
  • Coil embolization, Amplatzer duct occluder, PDA ligation: If continuous murmur present
  • Indomethacin or ibuprofen: Pharmacological closure in premature infants

Pulmonary Stenosis / 肺動脈狭窄症

• Overview
  • Congenital narrowing of pulmonary artery (most commonly pulmonary valve)
• Presentation
  • Asymptomatic: Compensated right heart function
• Examination
  • [Auscultation] Ejection click, systolic ejection murmur, weakened and pathological splitting of S2: Obstruction in pulmonary outflow
  • [ECG] Right ventricular hypertrophy: Right heart pressure overload
  • [Chest X-ray] Prominent left 2nd arc, rounded left 4th arc: Post-stenotic dilatation of pulmonary artery
  • [Echocardiography, right ventriculography] Stenotic valve, post-stenotic dilatation: Confirms diagnosis
  • [Cardiac catheterization] Pressure gradient between pulmonary artery and right ventricle, elevated right heart pressures: Quantifies stenosis severity
• Management
  • Observation: For mild cases
  • Percutaneous balloon pulmonary valvuloplasty (PTPV), surgical valvotomy: For moderate to severe cases

Coarctation of the Aorta / 大動脈縮窄症

• Overview
  • Local narrowing of aortic isthmus or descending aorta, classified into simple and complex types based on existence of associated defects
• Presentation
  • Asymptomatic: Gradual development of collateral circulation (simple CoA)
  • Dyspnea, pallor, oliguria, differential cyanosis: Heart failure and upper-lower body perfusion difference (complex CoA)
  • Weak/absent lower limb pulses, upper limb hypertension: Aortic narrowing
• Examination
  • [Auscultation] Accentuated S2, systolic murmur: Increased flow velocity at coarctation
  • [ECG] Left ventricular or biventricular hypertrophy: Cardiac strain
  • [Chest X-ray] 3-sign, rib notching, cardiomegaly, increased pulmonary vascularity: Collateral circulation and heart failure
  • [Echocardiography] Narrowing at aortic isthmus, associated defects: Confirms diagnosis
• Management
  • Balloon angioplasty, stent placement, aortic arch reconstruction: Intervention for pressure gradient ≥20mmHg (simple CoA)
  • Prostaglandin E1, aortic arch reconstruction with/without intracardiac repair: Urgent surgery (complex CoA)

Ruptured Aneurysm of the Sinus of Valsalva / Valsalva洞動脈瘤破裂

• Overview
  • Sudden rupture of aneurysm in right or non-coronary sinus into right ventricle/atrium
• Presentation
  • Sudden onset of palpitations, dyspnea, chest pain: Aneurysm rupture
  • Bounding pulse: Increased stroke volume due to left-to-right shunt
• Examination
  • [Auscultation] Continuous murmur: Shunt from aorta to right heart
  • [Chest X-ray] Prominence of left second arch, increased pulmonary vascularity: Pulmonary volume overload
  • [Echocardiography] Coronary sinus to right ventricle shunt: Confirms diagnosis
• Management
  • Aneurysm resection, fistula closure with patch: Early surgical intervention
  • VSD closure, aortic valve repair: If necessary

Tetralogy of Fallot / Fallot四徴症

• Overview
  • Congenital heart defect with four main features: pulmonary stenosis, ventricular septal defect, overriding aorta, right ventricular hypertrophy
• Presentation
  • Cyanosis (from neonatal period): Right-to-left shunt
  • Hypoxic spells (from 2-3 months): Right ventricular outflow tract spasm
  • Squatting posture (after age 2): Increases systemic vascular resistance
• Examination
  • [Auscultation] Systolic ejection murmur, single S2: PS, weak pulmonary component
  • [ECG] Right ventricular hypertrophy, right axis deviation: Right heart overload
  • [Chest X-ray] Boot-shaped heart, decreased pulmonary vascular markings: Characteristic findings
  • [Echocardiography] Pulmonary stenosis, ventricular septal defect, overriding aorta, right ventricular hypertrophy: Confirms diagnosis
• Management
  • Blalock-Taussig shunt: Subclavian artery to pulmonary artery shunt (palliative surgery)
  • VSD closure, right ventricular outflow tract reconstruction: Complete repair (after 6 months of age)
  • Sedation, oxygen, knee-chest position, β-blockers, α-agonists: Hypoxic spell management

Complete Transposition of the Great Arteries / 完全大血管転位症

• Overview
  • Aorta from right ventricle, pulmonary artery from left ventricle, classified into Types I-III based on associated defects
• Presentation
  • Cyanosis, tachypnea, respiratory distress: Separation of systemic and pulmonary circulations
• Examination
  • [Auscultation] Single and accentuated S2: Anterior displacement of aorta
  • [ECG] Right ventricular hypertrophy, right axis deviation: Right heart overlaod due to high resistance
  • [Chest X-ray] Egg-shaped cardiac silhouette: Characteristic findings
  • [Echocardiography] Aorta from right ventricle (anterior), pulmonary artery from left ventricle: Confirms diagnosis
• Management
  • PGE1 infusion, balloon atrial septostomy, diuretics: Emergency measures
  • Jatene procedure: Arterial switch operation (type I, II)
  • Rastelli procedure: Creates intracardiac tunnel to redirect blood flow (type III)

Total Anomalous Pulmonary Venous Return / 総肺静脈還流異常症

• Overview
  • All four pulmonary veins drain into the right heart system
• Presentation
  • Respiratory distress, right heart failure symptoms, cyanosis: Abnormal pulmonary venous return
• Examination
  • [Auscultation] Accentuated S2: Pulmonary hypertension
  • [ECG] Right ventricular hypertrophy, right axis deviation: Right heart strain
  • [Chest X-ray] Cardiomegaly, increased pulmonary vascular markings, snowman appearance (Type Ia): Right heart volume overload and pulmonary congestion
  • [Echocardiography, MDCT] Enlarged right atrium and ventricle, abnormal pulmonary vein course: Confirms diagnosis
• Management
  • Anastomosis of common pulmonary vein to left atrium, ASD closure: Urgent intracardiac repair

Tricuspid Atresia / 三尖弁閉鎖症

• Overview
  • Absent tricuspid valve blocking right atrium-ventricle communication, always with ASD
• Presentation
  • Cyanosis, heart failure symptoms: Right-to-left shunt
• Examination
  • [ECG] Left ventricular hypertrophy, left axis deviation: Right-to-left shunt through ASD
  • [Chest X-ray] Prominent left 4th arc: Left ventricular enlargement
  • [Echocardiography] Absence of right atrium-right ventricle communication: Confirms diagnosis
• Management
  • PGE1 administration, Blalock-Taussig shunt: For decreased pulmonary flow type (palliative treatment)
  • Pulmonary artery banding: For increased pulmonary flow type (palliative treatment)
  • Bidirectional Glenn procedure, Fontan procedure: Connect SVC and IVC to pulmonary artery

Ebstein’s Anomaly / Ebstein病

• Overview
  • Malformation of right ventricle and tricuspid valve causing tricuspid regurgitation
• Presentation
  • Cyanosis, heart failure symptoms: Severity varies widely
• Examination
  • [Auscultation] Holosystolic murmur, S3, S4: TR, heart failure
  • [ECG] Right atrial P waves, prolonged PQ interval, right bundle branch block, WPW syndrome: Conduction abnormalities
  • [Chest X-ray] Prominent right second arc: Enlarged right atrium
  • [Echocardiography] Tricuspid valve displaced towards right ventricle, tricuspid regurgitation: Confirms diagnosis
• Management
  • Observation: For mild cyanosis and heart failure symptoms
  • Tricuspid valve repair (Carpentier procedure), ASD closure if needed: For severe cyanosis or heart failure
  • Starnes procedure, Fontan operation: For severe neonatal cases

Arterial Disorder / 動脈疾患

Aortic Aneurysm / 大動脈瘤

• Overview
  • Abnormal dilation of aorta due to atherosclerosis, potentially fatal if ruptured
  • More common in middle-aged and elderly men
• Presentation
  • Asymptomatic: Most common
  • Hoarseness, Horner’s syndrome: Compression of recurrent laryngeal nerve or sympathetic nerves
  • Dysphagia, nausea, vomiting: Compression of esophagus
  • Cough, hemoptysis, dyspnea: Compression of trachea or lungs
  • Altered consciousness, abdominal pain, leg numbness: Organ ischemia
• Examination
  • [Physical] Pulsatile abdominal mass: Expansion of abdominal aorta
  • [Chest X-ray] Widened mediastinal shadow: Expansion of thoracic aorta
  • [CT, MRI, Ultrasound] Aneurysm: Confirmation of size and location
• Management
  • Lifestyle modification, blood pressure control: Conservative management
  • Artificial graft replacement, endovascular stent grafting: If aneurysm >5-6 cm or rapid expansion

Ruptured Aortic Aneurysm / 大動脈瘤破裂

• Overview
  • Life-threatening complication of aortic aneurysm
• Presentation
  • Sudden severe chest/back/lumbar pain, anemia, shock: Rupture and rapid blood loss
  • Hemoptysis, hematemesis: Blood leaking into adjacent structures
• Examination
  • [CT, Ultrasound] Aneurysm and hematoma: Confirmation of rupture
• Management
  • Artificial graft replacement, endovascular stent grafting, open stent grafting: Immediate intervention required

Aortic Dissection / 大動脈解離

• Overview
  • Tear in aortic intima leads to blood flow separating the medial layer and forming a false lumen, high mortality rate
  • Risk factors: Chronic hypertension, congenital connective tissue disorders
• Presentation
  • Sudden severe chest/back pain: Aortic wall disruption
  • Hypertension, blood pressure difference between arms: Organ ischemia
• Examination
  • [ECG] No specific findings: Rules out myocardial infarction
  • [Blood] Elevated D-dimer: Indicates thrombosis
  • [Chest X-ray] Widened mediastinal shadow: Aortic dilatation
  • [CT] Intimal flap, true and false lumens: Confirms diagnosis
  • [Echocardiography] Aortic regurgitation, pericardial effusion: Complications
• Management
  • [Stanford Type A] Emergency surgical graft replacement: Involving ascending aorta
  • [Stanford Type B] Blood pressure and heart rate control, pain management: Not involving ascending aorta
  • [Stanford Type B] Endovascular stent graft: For complications or refractory cases

Takayasu’s Arteritis / 高安動脈炎

• Overview
  • Chronic vasculitis affecting aorta and its major branches
  • More common in young women
• Presentation
  • Fever, fatigue: Systemic inflammation
  • Dizziness, syncope: Common carotid artery stenosis
  • Upper limb numbness/coldness: Subclavian artery stenosis
  • Heart murmur: Often due to aortic regurgitation
• Examination
  • [Physical] Weak/absent pulses, BP differences, bruits: Vascular stenosis
  • [Blood] ESR↑, CRP↑, WBC↑, γ-globulin↑: Inflammatory markers
  • [DSA, CT, MRA, FDG-PET] Vessel wall calcification, stenosis/occlusion/dilation: Confirms diagnosis
• Management
  • Corticosteroids, immunosuppressants: Suppress inflammation
  • Surgery: For cardiac or aortic lesions

Arteriosclerosis Obliterans / 閉塞性動脈硬化症

• Overview
  • Chronic occlusive disease of arteries in lower limbs due to arteriosclerosis
  • Common in males over 50 with risk factors of atherosclerosis
• Presentation
  • Intermittent claudication, rest pain, ulcers/necrosis: Chronic lower limb ischemia
• Examination
  • [Physical] Weakened or absent arterial sounds, ankle-brachial index (ABI) ≤ 0.9: Reduced blood flow
  • [Angiography, ultrasound, MRA, CTA] Arterial stenosis or occlusion: Confirms diagnosis
• Management
  • Exercise therapy, antiplatelet drugs (cilostazol), vasodilators: For intermittent claudication
  • Percutaneous transluminal angioplasty (PTA), stenting, bypass surgery, thromboembolectomy: For severe ischemia

Thromboangiitis Obliterans / 閉塞性血栓血管炎

• Overview
  • Inflammatory occlusive disease of arteries in distal extremities
  • Affects male smokers under 50
• Presentation
  • Cold sensation, numbness, Raynaud’s phenomenon in extremities: Reduced blood flow
  • Intermittent claudication, painful ulcers/necrosis in fingers or toes: Progressive vascular occlusion
• Examination
  • [Doppler] Decreased ankle blood pressure, low ankle-brachial index (ABI): Reduced distal blood flow
  • [Angiography] Abrupt vessel cutoffs, corkscrew collaterals: Characteristic vascular changes
• Management
  • Smoking cessation: Essential for disease control
  • Antiplatelet drugs (cilostazol), vasodilators: Improve blood flow
  • Sympathectomy, bypass surgery, amputation: Surgical interventions

Acute Arterial Occlusive Disease / 急性動脈閉塞症

• Overview
  • Sudden occlusion of peripheral arteries due to embolism or thrombosis, high mortality rate if not treated
  • Risk factors: Atrial fibrillation, cardiac myxoma, hypercoagulability, atherosclerosis
• Presentation
  • Pain, pulselessness, pallor, paralysis, paresthesia (5P): Acute limb ischemia
• Examination
  • [Physical] Absent peripheral pulses, decreased ankle-brachial index (ABI): Signs of arterial occlusion
  • [Ultrasound, angiography, MDCT, MRA] Arterial occlusion: Confirms diagnosis
• Management
  • Urgent thromboembolectomy, catheter-directed thrombolysis, bypass surgery: Revascularization
  • Anticoagulants (heparin): Conservative treatment

Venous Disorder / 静脈疾患

Varicose Vein of the Lower Extremity / 下肢静脈瘤

• Overview
  • Dilated and tortuous superficial veins in lower limbs due to venous valve incompetence
  • More common in women over 30, influenced by pregnancy, prolonged standing, obesity, aging
• Presentation
  • Dilated and tortuous veins: Venous reflux and stasis
  • Dull pain, heaviness, itching, eczema, skin pigmentation: Chronic blood stasis
• Examination
  • [Ultrasound] Reflux and valve incompetence in superficial veins: Confirms diagnosis
• Management
  • Compression stockings, leg elevation: Conservative therapy to improve venous return
  • Endovenous ablation, stripping, varicectomy, sclerotherapy: Occlusion or removal of incompetent veins

Deep Vein Thrombosis / 深部静脈血栓症

• Overview
  • Thrombosis in deep veins of lower limbs, can lead to pulmonary thromboembolism
  • Risk factors: Surgery, trauma, prolonged bed rest, intravenous catheterization, pregnancy, malignancy
• Presentation
  • Unilateral leg swelling, superficial vein dilation, color changes: Venous obstruction and congestion
  • Leg tension, pain, Homans’ sign: Vascular inflammation
• Examination
  • [Blood] D-dimer↑, FDP↑: Fibrin degradation products
  • [Ultrasound] Reduced blood flow: Venous obstruction
  • [Contrast CT] Confirmation of thrombus: Definitive diagnosis
• Management
  • Anticoagulation (heparin, warfarin, DOACs): Prevent clot propagation
  • Thrombolysis (urokinase): Dissolve existing clots
  • Catheter-directed therapy, surgical thrombectomy: For severe cases
  • Early ambulation, compression stockings, intermittent compression: Reduce risk in high-risk situations

Superior Vena Cava Syndrome / 上大静脈症候群

• Overview
  • Obstruction of venous return through superior vena cava, often caused by malignant tumors or aortic aneurysms
• Presentation
  • Edema of head/face/unilateral arm, headache, dyspnea: Upper body congestion
  • Distended neck and upper body superficial veins: Impaired venous return
• Examination
  • [Chest X-ray] Widened upper mediastinum: Mass effect
  • [CT, MRI] Stenosis or occlusion of superior vena cava: Definitive diagnosis
• Management
  • Treatment of underlying cause: Malignant tumors, benign mediastinal tumors, thoracic aortic aneurysm
  • Stent placement, bypass surgery: Endovascular or surgical treatment

Lymphedema / リンパ浮腫

• Overview
  • Impaired lymphatic drainage causing tissue swelling,
  • Primary (rare) or secondary (often due to cancer treatment)
• Presentation
  • Unilateral or bilateral limb swelling: Impaired lymph drainage
• Examination
  • [Physical] Asymmetric limb swelling, skin changes: Visual and tactile assessment
• Management
  • Limb elevation, compression stockings, massage, infection prevention: Complex decongestive therapy
  • Lymphaticovenous anastomosis: For refractory cases

Blood Pressure Disorder / 血圧異常

Essential Hypertension / 本態性高血圧

• Overview
  • High blood pressure without identifiable cause
  • Accounts for about 90% of hypertension cases
• Presentation
  • Asymptomatic: Gradual onset and progression
• Examination
  • [Blood Pressure] ≥140/90 mmHg: Persistent elevation of blood pressure
• Management
  • Salt reduction, weight loss, exercise, smoking cessation, alcohol moderation: Lifestyle modifications
  • CCBs, ARBs, ACE inhibitors, MRAs, diuretics, β-blockers: Vasodilation, fluid excretion, cardiac output reduction

Malignant Hypertension / 加速型悪性高血圧

• Overview
  • Severe hypertension with rapid progression of organ damage
  • More common in males 40-50 years old
• Presentation
  • Headache, visual disturbances: Hypertensive encephalopathy
  • Oliguria, uremia: Rapidly progressing renal dysfunction
  • Heart failure symptoms: Cardiac overload
• Examination
  • [Blood pressure] Diastolic BP ≥120-130 mmHg: Severe elevation of blood pressure
  • [Fundoscopy] Retinal hemorrhages, papilledema: Hypertensive retinopathy
• Management
  • Immediate IV or oral antihypertensives: Hypertensive emergency
  • Dialysis: For severe renal dysfunction

Renovascular Hypertension / 腎血管性高血圧

• Overview
  • Hypertension caused by renal artery stenosis and increased RAA system activity
  • Common in patients <30 or >60 years old
• Presentation
  • Treatment-resistant or malignant hypertension: Due to persistent RAAS activation
  • Worsening renal function after ACE inhibitors or ARBs: Impaired glomerular filtration
• Examination
  • [Auscultation] Abdominal bruit: Severe vascular stenosis
  • [Ultrasound, MR/CT angiography] Renal artery stenosis: Primary screening method
  • [Blood] Elevated plasma renin activity (PRA): RAAS activation
• Management
  • Combination of antihypertensives: ACE inhibitors/ARBs contraindicated in bilateral cases
  • Percutaneous transluminal renal angioplasty (PTRA): For significant stenosis

Hypotension / 低血圧

• Overview
  • Low blood pressure due to various causes, including essential hypotension, orthostatic hypotension, postprandial hypotension
• Presentation
  • Asymptomatic: Especially in essential hypotension
  • Dizziness, fatigue, syncope: Inadequate cerebral perfusion
• Examination
  • [Blood pressure] Systolic BP <100 mmHg: Basic diagnostic criteria
  • [Orthostatic test] BP drop after standing (≥20 mmHg systolic or ≥10 mmHg diastolic): Diagnoses orthostatic hypotension
• Management
  • Improve sleep, diet, exercise habits: Lifestyle modifications
  • Sympathomimetics, mineralocorticoids: Vasoconstriction, increase plasma volume

Pulmonology/ 呼吸器科

Infectious Disorder / 感染性疾患

Common Cold Syndrome / かぜ症候群

• Overview
  • Most common respiratory infection affecting upper respiratory tract mucosa, mostly caused by viruses
  • Transmitted through droplets and contact
• Presentation
  • Rhinorrhea, nasal congestion, sneezing: Nasal inflammation
  • Sore throat, dry throat, hoarseness: Upper respiratory tract inflammation
  • Cough, sputum: Lower respiratory tract inflammation
  • Mild fever, headache, fatigue: Systemic inflammatory response
• Examination
  • Clinical
• Management
  • Rest, warmth, gargling, hand washing: Supportive care
  • Traditional medicines (Kakkonto, Maoto), acetaminophen, NSAID, antihistamine: Symptom relief

Acute Bronchiolitis / 急性細気管支炎

• Overview
  • Acute inflammation of bronchioles causing airway narrowing and obstruction, mainly caused by RSV and parainfluenza virus
  • Most common in infants under 1 year
• Presentation
  • Fever, cough, rhinorrhea: Initial cold-like symptoms
  • Expiratory wheezing: Bronchiolar narrowing
  • Nasal flaring, chest retractions, tachypnea: Respiratory distress
• Examination
  • [Antigen test] Positive for RSV: Confirm diagnosis
• Management
  • Oxygen therapy, nebulizer humidification, IV fluids: Supportive care

Influenza / インフルエンザ

• Overview
  • Infectious disease with seasonal epidemic caused by influenza virus, more severe than common cold and can be fatal
  • Transmitted through droplets and contact, common in winter to spring
• Presentation
  • High fever (>38°C), chills, headache, muscle/joint pain, fatigue: Rapid onset systemic symptoms
  • Cough, sore throat, rhinorrhea: Respiratory symptoms
• Examination
  • [Antigen test]] Positive for influenza virus: Confirm diagnosis
• Management
  • Neuraminidase inhibitor (Oseltamivir, Zanamivir), RNA polymerase inhibitor (Favipiravir): Shorten fever duration, prevent severe complications

COVID-19 / 新型コロナウイルス感染症

• Overview
  • Novel infectious disease caused by SARS-CoV-2, can be severe and fatal especially in elderly or immunocompromised patients
  • Transmitted through droplets and contact
• Presentation
  • Fever, fatigue, dry cough, shortness of breath: Systemic and respiratory symptoms
  • Loss of smell/taste: Characteristic symptoms
  • Acute respiratory distress syndrome, thrombotic events, shock, organ failure: Complications in severe cases
• Examination
  • [PCR, Antigen test] Positive for SARS-CoV-2: Confirm diagnosis
  • [Blood] Lymphopenia: Indicates disease severity
  • [Blood] D-dimer elevation: Suggests thromboembolism/DIC
• Management
  • Remdesivir, Molnupiravir, Nirmatrelvir, Ritonavir: Antiviral treatment
  • Dexamethasone, Baricitinib, Tocilizumab (severe case): Anti-inflammatory treatment
  • Mechanical ventilation (severe case): Respiratory support

Bacterial Pneumonia / 細菌性肺炎

• Overview
  • Acute purulent inflammation of lung caused by bacterial infection
  • [Streptococcus pneumoniae] 1st common
  • [Haemophilus influenzae] 2nd common
  • [Klebsiella pneumoniae] Often serious in underlying diseases
  • [Staphylococcus aureus] Often with local destruction
  • [Moraxella catarrhalis] Often cause deterioration of COPD
  • [Pseudomonas aeruginosa] Often in immunocompromised or ventilator-associated
• Presentation
  • Cough, purulent sputum, chest pain, dyspnea: Local inflammation of lung
  • Fever, fatigue, loss of appetite: Systemic inflammatory response
• Examination
  • [Physical] Dullness on percussion, decreased breath sounds, coarse crackles: Consolidation of lung tissue
  • [Blood] WBC↑, CRP↑, ESR↑, hypoxemia: Inflammatory response
  • [Chest X-ray, CT] Infiltrative shadows, air bronchogram: Alveolar filling
  • [Sputum] Gram stain, culture, rapid antigen test: Identify causative bacteria
• Management
  • Antibiotics based on pathogen: Target causative bacteria
  • Rest, temperature/fluid/electrolyte control: Supportive care
  • Oxygen therapy, mechanical ventilation: Treat respiratory failure

Aspiration Pneumonia / 誤嚥性肺炎

• Overview
  • Pneumonia caused by aspiration due to swallowing dysfunction, aspiration often silent
  • Common in elderly, major cause of healthcare-associated pneumonia
• Presentation
  • Decreased ADL, appetite loss, incontinence: Atypical symptoms in elderly
  • Less fever, cough, or sputum: May lack typical pneumonia symptoms
• Examination
  • [Physical] Respiratory rate↑, SpO2↓: Impaired gas exchange
  • [Blood] WBC↑, CRP↑, ESR↑: Inflammatory response
  • [Chest X-ray] Infiltrative shadows: Alveolar filling
• Management
  • Empiric antibiotics: Cover anaerobes and streptococci
  • Prevention: Swallowing rehabilitation, oral care, proper positioning

Chlamydial Pneumonia / クラミジア肺炎

• Overview
  • Atypical pneumonia caused by C. pneumoniae, C. trachomatis, C. psittaci (psittacosis)
  • Common in young adults and elderly, bird exposure (psittacosis)
• Presentation
  • Persistent dry cough, mild fever: Atypical pneumonia pattern
  • [Psittacosis] Dry cough, high fever >39℃, headache, relative bradycardia, hepatosplenomegaly: More severe systemic symptoms
• Examination
  • [Clinical] No response to β-lactams: Characteristic of atypical bacteria
  • [Antibody/Gene test] Positive for chlamydia: Confirm diagnosis
• Management
  • Tetracyclines, macrolides, fluoroquinolones: Target atypical bacteria

Mycoplasma Pneumonia / マイコプラズマ肺炎

• Overview
  • Atypical pneumonia caused by Mycoplasma pneumoniae, transmitted by contact/droplets
  • Common in healthy young people
• Presentation
  • Persistent dry cough, minimal physical findings: Atypical pneumonia pattern
  • Fever, headache, fatigue: Systemic symptoms
• Examination
  • [Clinical] No response to β-lactams: Characteristic of atypical bacteria
  • [Blood] WBC→, ESR↑, CRP↑, cold agglutinin(+): Non-specific inflammation
  • [Antibody/Gene test] Positive for mycoplasma: Confirm diagnosis
• Management
  • Macrolides, tetracyclines, fluoroquinolones: Target atypical bacteria

Legionella Pneumonia / レジオネラ肺炎

• Overview
  • Pneumonia caused by inhaling aerosols containing Legionella
  • Common in middle-aged adults with exposure to water systems (hot springs, circulating baths)
• Presentation
  • High fever, cough, chest pain: Inflammation of lungs
  • Relative bradycardia, neuropsychiatric symptoms, diarrhea: Characteristic of Legionella pneumonia
• Examination
  • [Blood] Na↓, CK↑: Characteristic laboratory findings
  • [Chest X-ray] Infiltrates, pleural effusion: Lung involvement
  • [Clinical] No response to β-lactams: Characteristic of atypical bacteria
  • [Urine antigen] Positive for Legionella: Rapid diagnosis
  • [Sputum] Culture on BCYEα agar: Confirmatory tests
• Management
  • Fluoroquinolones, macrolides (IV): First-line treatment
  • Rifampicin, tetracyclines: Alternative options

Cytomegalovirus Pneumonia / サイトメガロウイルス肺炎

• Overview
  • CMV acquired in childhood and remains latent, reactivates in immunocompromised patients
  • Common in patients on steroids/immunosuppressants, malignancy, HIV/AIDS
• Presentation
  • Fever, dyspnea, dry cough: Inflammation of lungs
• Examination
  • [Chest X-ray] Bilateral diffuse ground-glass opacities: Interstitial pneumonia
  • [Sputum, Lung biopsy] Giant cells with nuclear inclusions: Characteristic finding
  • [Gene/Antigen test] Positive for CMV: Confirmatory test
• Management
  • Ganciclovir, valganciclovir: First-line antiviral treatment
  • Foscarnet: For drug-resistant cases

Lung Abscess / 肺膿瘍

• Overview
  • Severe complication of pneumonia with destruction of lung tissue forming pus-filled cavity
  • Common in alcoholics, diabetics
• Presentation
  • Fever, cough, foul-smelling sputum, hemoptysis: Purulent inflammation and tissue destruction
  • Chest pain: When lesion reaches pleura
• Examination
  • [Blood] WBC↑, CRP↑: Infection
  • [CT] Well-defined mass, air-fluid level (niveau): Abscess formation
• Management
  • Combination antibiotics: Target multiple bacterial species
  • Drainage: For persistent cases

Pulmonary Tuberculosis / 肺結核症

• Overview
  • Respiratory infection caused by Mycobacterium tuberculosis, classified as primary (initial infection) and secondary (reactivation)
• Presentation
  • Cough >2 weeks, sputum, hemoptysis: Active infection in airways
  • Fever, fatigue, night sweat: Systemic inflammatory response
• Examination
  • [Chest X-ray] Hilar lymphadenopathy, nodular shadows, cavitary lesions: Different stages of infection
  • [CT] Bronchiolar nodules (tree-in-bud sign): Bronchiolar spread of infection
  • [Sputum smear] Fluorescent or red-stained bacilli with Ziehl-Neelsen stain: Acid-fast bacteria
  • [Culture, PCR] Identification of M. tuberculosis: Confirmatory test
• Management
  • Multi-drug therapy with RFP, INH, PZA, EB/SM: Different mechanisms to prevent drug resistance

Miliary Tuberculosis / 粟粒結核

• Overview
  • Hematogenous spread of tuberculosis forming multiple tubercles in various organs
  • Common in children, elderly, immunocompromised patients
• Presentation
  • Persistent high fever, headache, fatigue: Systemic infection
• Examination
  • [Blood] ESR↑, CRP↑: Systemic inflammation
  • [Tuberculin test] Sometimes negative: Anergic state due to overwhelming infection
  • [Chest X-ray] Diffuse miliary nodules in both lungs: Disseminated infection
  • [Biopsy, Culture] Identification of M. tuberculosis: Confirmatory test
• Management
  • Multi-drug therapy with RFP, INH, PZA, EB/SM: Different mechanisms to prevent drug resistance

MAC Disease / 非結核性抗酸菌症

• Overview
  • Caused by Mycobacterium avium complex, environmental organism without human-to-human transmission
  • Common in patients without underlying disease (nodular/bronchiectatic), patients with previous TB or COPD (fibrocavitary), younger patients (hypersensitivity)
• Presentation
  • Cough, sputum, hemoptysis: Airway infection
• Examination
  • [Chest X-ray, CT] Multiple nodules with bronchiectasis, upper lobe cavities, diffuse ground-glass opacities: Nodular/bronchiectatic, fibrocavitary, or hypersensitivity type
  • [Sputum culture] Positive MAC cultures: Confirmatory test
• Management
  • Multi-drug therapy with CAM, RFP, EB: Different mechanisms to prevent drug resistance
  • Lobectomy: Surgical option for localized disease

Simple Pulmonary Aspergilloma / 単純性肺アスペルギローマ

• Overview
  • Aspergillus colonization in pre-existing lung cavity forming fungus ball
  • Common in patients with previous tuberculosis, fibrosis, emphysema
• Presentation
  • Asymptomatic
  • Fever, cough, hemoptysis: Local inflammation
• Examination
  • [Chest X-ray, CT] Fungus ball, meniscus sign, thickened cavity wall and pleura: Characteristic findings
  • [Blood] Anti-aspergillus precipitating antibodies (+): Immune response to infection
  • [Sputum, BALF, TBLB] Fungal hyphae, positive culture: Confirms diagnosis
• Management
  • Surgical resection: Curative treatment
  • Voriconazole, itraconazole: For inoperable cases

Chronic Progressive Pulmonary Aspergillosis / 慢性進行性肺アスペルギルス症

• Overview
  • Progressive Aspergillus infection with cavity expansion and infiltrates
  • Common in patients with pre-existing lung cavities or immunocompromised states
• Presentation
  • Persistent cough, sputum/hemoptysis, fever, weight loss: Chronic inflammation
• Examination
  • [Chest X-ray] New/expanding cavities, thickened cavity walls, air-fluid levels: Progressive nature of disease
  • [Blood] WBC↑, CRP↑, ESR↑: Chronic inflammation
  • [Blood] Anti-aspergillus precipitating antibodies (+), galactomannan antigen (+): Fungal infection markers
  • [Sputum, BALF, TBLB] Fungal hyphae, positive culture: Confirms diagnosis
• Management
  • Micafungin, voriconazole, caspofungin, amphotericin B: Target fungal cells

Invasive Pulmonary Aspergillosis / 侵襲性肺アスペルギルス症

• Overview
  • Severe Aspergillus infection with tissue invasion
  • Common in immunocompromised patients (neutropenia, leukemia, GVHD, steroid, immunosuppressant)
• Presentation
  • Sudden fever, cough, hemoptysis: Aggressive fungal invasion
• Examination
  • [Chest X-ray] Rapidly progressing wedge-shaped shadows: Vascular invasion
  • [CT] Halo sign, air crescent sign: Characteristic findings
  • [Blood] β-D-glucan↑, galactomannan antigen (+): Fungal infection markers
  • [Sputum, BALF, TBLB] Fungal hyphae, positive culture: Confirms diagnosis
• Management
  • Voriconazole, amphotericin B, itraconazole, micafungin, caspofungin Target fungal cell

Pulmonary Cryptococcosis / 肺クリプトコックス症

• Overview
  • Infection by Cryptococcus neoformans through inhalation from soil contaminated with bird droppings
  • Occurs in both immunocompetent and immunocompromised patients
• Presentation
  • [Immunocompetent] Asymptomatic, mild fever, cough: Limited immune response
  • [Immunocompromised] Fever, fatigue, chest pain, dyspnea, cough, hemoptysis: More severe symptoms due to poor immune function
• Examination
  • [Chest X-ray, CT] Solitary/multiple nodules, cavitation, infiltrates: Different patterns based on immune status
  • [Blood] GXM antigen (+): Confirms diagnosis
• Management
  • Fluconazole ,itraconazole, voriconazole, amphotericin B,: Target fungal cells

Pneumocystis Pneumonia / ニューモシスチス肺炎

• Overview
  • Severe pneumonia caused by Pneumocystis jirovecii in immunocompromised patients
  • Common in patents with AIDS, malignancy, autoimmune disease, steroid, immunosuppressant
• Presentation
  • Sudden fever, dry cough, dyspnea: Acute inflammatory response
• Examination
  • [Blood] LDH↑, KL-6↑, β-D-glucan↑, PaO2↓: Lung damage and fungal infection markers
  • [Chest X-ray, CT] Diffuse ground-glass opacity, multiple cystic shadows: Characteristic radiological findings
  • [Sputum, BALF, TBLB] Detection of pneumocystis: Confirms diagnosis
• Management
  • Trimethoprim-sulfamethoxazole, pentamidine, atovaquone: Target fungal cells
  • Steroids: For severe respiratory compromise

Immune and Allergic Disorder / 免疫・アレルギー性疾患

Acute Eosinophilic Pneumonia / 急性好酸球性肺炎

• Overview
  • Rapidly progressive diffuse eosinophilic lung infiltration
  • Common in young males within 1 month of starting smoking
• Presentation
  • Fever, dyspnea, dry cough, chest pain: Acute inflammatory response and lung infiltration
  • Severe hypoxemia: Rapid onset respiratory failure
• Examination
  • [Chest X-ray] Diffuse ground-glass opacity/infiltrates, Kerley B lines, pleural effusion: Lung inflammation and edema
  • [Blood] CRP↑: Acute inflammation
  • [BALF] Eosinophils↑: Diagnostic criteria
• Management
  • High-dose steroids: Good prognosis

Chronic Eosinophilic Pneumonia / 慢性好酸球性肺炎

• Overview
  • Subacute to chronic eosinophilic lung infiltration
  • Common in middle-aged women with allergic history
• Presentation
  • Fever, cough, sputum, dyspnea,: Chronic inflammatory response and lung infiltration
  • Weight loss, general fatigue: Chronic inflammatory condition
• Examination
  • [Chest X-ray] Migratory peripheral infiltrates: Characteristic findings
  • [Blood] Eosinophils↑, CRP↑: Eosinophilic inflammation
  • [BALF, Lung biopsy] Eosinophils↑: Confirms diagnosis
• Management
  • High-dose steroids followed by gradual reduction: Good prognosis but high relapse rate

Allergic Bronchopulmonary Aspergillosis / アレルギー性気管支肺アスペルギルス症

• Overview
  • Allergic respiratory disease caused by Aspergillus species
  • Common in patients with atopic predisposition
• Presentation
  • Fever, cough, paroxysmal dyspnea: Allergic bronchial response
  • Thick brownish sputum: Mucoid impaction
• Examination
  • [Blood] Eosinophils↑, IgE↑, specific IgE to Aspergillus: Allergic response
  • [PFT] FEV1%↓, %VC→or↓: Obstructive or mixed ventilatory disorder
  • [Chest X-ray, CT] Recurrent transient infiltrates, central bronchiectasis, mucoid plugging: Characteristic findings
  • [Skin test] Immediate reaction to Aspergillus antigen: Type I allergy
• Management
  • Systemic steroids: Control asthma
  • Itraconazole: Antifungal therapy

Hypersensitivity Pneumonitis / 過敏性肺臓炎

• Overview
  • Diffuse granulomatous interstitial pneumonia caused by repeated inhalation of antigens
  • Commonly improves with environment change but relapses with re-exposure
• Presentation
  • Fever, dry cough, dyspnea on exertion, fine crackles: Interstitial inflammation
• Examination
  • [Blood] WBC↑, ESR↑, CRP↑, IgE→, eosinophils→, specific antibody: Inflammatory response
  • [PFT] %VC↓, FEV1%→, PaO2↓, DLCO↓: Restrictive ventilatory disorder with diffusion impairment
  • [Chest X-ray, HRCT] Bilateral diffuse ground-glass opacities, nodular shadows: Interstitial inflammation
  • [BALF] T-cells↑, CD4/CD8 ratio varies by type: Immunological abnormality
  • [Inhalation test] Positive inhalation challenge test: Confirm diagnosis
• Management
  • Antigen avoidance: Primary treatment
  • Corticosteroids: For severe or persistent cases

Sarcoidosis / サルコイドーシス

• Overview
  • Non-caseating epithelioid granulomatous disease involving multiple organs
  • Common in young adults and middle-aged women
• Presentation
  • Fatigue, fever, joint pain: Systemic inflammation
  • Cough, exertional dyspnea: Pulmonary involvement
  • Visual disturbance, photophobia, floaters: Ocular involvement
  • Erythema nodosum, scar infiltration: Cutaneous involvement
  • Facial nerve palsy, diabetes insipidus: Neurological involvement
  • Advanced AV block: Cardiac involvement
  • Hypercalcemia: Renal involvement
• Examination
  • [Chest X-ray] Bilateral hilar lymphadenopathy, Ga-67 increased uptake: Active inflammation
  • [Blood] Lymphocytes↓, γ-globulin↑, ACE↑, Ca↑: Systemic inflammation
  • [BALF] Lymphocytes↑, CD4/CD8 ratio↑: Local inflammation
  • [Tuberculin test] Negative conversion: Decreased cellular immunity
  • [Biopsy] Non-caseating epithelioid granuloma: Diagnostic finding
• Management
  • Observation: Often resolve spontaneously
  • Corticosteroids: For serious cases

Microscopic Polyangiitis / 顕微鏡的多発血管炎

• Overview
  • Necrotizing vasculitis affecting lungs and kidneys
  • Common in 50-70s
• Presentation
  • Alveolar hemorrhage, interstitial pneumonia: Pulmonary involvement
  • Hematuria, proteinuria, casts, rapidly progressive glomerulonephritis: Renal involvement
  • Fever, weight loss, fatigue, myalgia, arthralgia: Systemic inflammation
  • Purpura, GI bleeding, mononeuritis multiplex: Multi-organ involvement
• Examination
  • [Blood] CRP↑, WBC↑, MPO-ACNA(+): Systemic inflammation
  • [Blood] BUN↑, Cr↑: Renal damage
• Management
  • Steroids, high-dose steroids + cyclophosphamide pulse: Induction therapy
  • Low-dose steroids + immunosuppressants: Maintenance therapy

Eosinophilic Granulomatosis with Polyangiitis / 好酸球性多発血管炎性肉芽腫症

• Overview
  • Granulomatous necrotizing vasculitis with eosinophilic infiltration affecting upper airways and peripheral nerves
  • Common in 40-60s
• Presentation
  • Asthma, eosinophilic sinusitis: Respiratory tract involvement
  • Numbness, muscle weakness: Neurological involvement
  • Fever, weight loss: Systemic inflammation
  • GI bleeding, purpura, arthralgia, myalgia: Multi-organ involvement
• Examination
  • [Blood] CRP↑, WBC↑ (eosinophilia), platelets↑, IgE↑, RF(+), MPO-ANCA(+): Systemic inflammation
  • [Chest X-ray] Migratory infiltrates: Eosinophilic pneumonia
  • [Biopsy] Granulomatous necrotizing vasculitis with eosinophilic infiltration: Confirms diagnosis
• Management
  • Moderate-dose steroids: Control inflammation
  • High-dose steroids + cyclophosphamide pulse, IVIG, anti-IL-5: For severe or resistant cases

Granulomatosis with Polyangiitis / 多発血管炎性肉芽腫症

• Overview
  • Necrotizing granulomatous vasculitis affecting upper airways, lungs, and kidneys
  • Common in 40-50s
• Presentation
  • Otitis media, chronic sinusitis, oral ulcers, exophthalmos: Upper airway involvement
  • Hemoptysis, cough, dyspnea: Pulmonary involvement
  • Hematuria, proteinuria, edema, hypertension: Renal involvement
  • Fever, weight loss: Systemic inflammation
  • Purpura, arthritis, episcleritis, mononeuritis multiplex: Multi-organ involvement
• Examination
  • [Blood] CRP↑, WBC↑, PR3-ANCA or MPO-ANCA(+): Systemic inflammation
  • [Blood] BUN↑, Cr↑: Renal damage
  • [Chest X-ray/CT] Multiple nodules with cavitation: Granulomatous inflammation
  • [Biopsy] Necrotizing granulomas with giant cells: Confirms diagnosis
• Management
  • High-dose steroids + cyclophosphamide pulse: Induction therapy
  • Low-dose steroids + immunosuppressants: Maintenance therapy

Goodpasture Syndrome / Goodpasture症候群

• Overview
  • Autoimmune disease caused by anti-GBM antibodies targeting basement membranes in lungs and kidneys
• Presentation
  • Cough, hemoptysis, dyspnea: Pulmonary involvement
  • Hematuria, proteinuria, oliguria/anuria: Renal involvement
• Examination
  • [Sputum] Hemosiderin-laden macrophages: Alveolar hemorrhage
  • [Chest X-ray] Diffuse reticulonodular infiltrates: Alveolar damage
  • [PFT] Restrictive pattern, DLCO↑: Alveolar damage
  • [Urine] Proteinuria, hematuria: Glomerular damage
  • [Blood] Anti-GBM antibodies(+): Confirms diagnosis
  • [Biopsy] Linear IgG deposits along basement membranes: Definitive diagnosis
• Management
  • High-dose steroids + immunosuppressants: Control inflammation
  • Plasma exchange: Remove anti-GBM antibodies
  • Dialysis: For severe renal dysfunction

Interstitial Lung Disease / 間質性肺疾患

Idiopathic Pulmonary Fibrosis / 特発性肺線維症

• Overview
  • Progressive lung fibrosis and honeycomb formation
  • Common in male smokers over 50
• Presentation
  • Dry cough, exertional dyspnea, fine crackles: Progressive lung fibrosis
  • Clubbing: Chronic hypoxemia
• Examination
  • [Blood] LDH↑, ESR↑, CRP↑, WBC↑, IgG↑, KL-6↑, SP-A↑, SP-D↑: Inflammation and tissue damage
  • [PFT] VC↓, DLCO↓, PaO2↓, A-aDO2↑: Restrictive ventilatory disorder and diffusion impairment
  • [HRCT, X-ray] Honeycomb pattern with reticular shadows: Characteristic fibrotic changes
• Management
  • Pirfenidone, nintedanib: Anti-fibrotic effect
  • N-acetylcysteine inhalation: Antioxidant effect
  • Steroids, immunosuppressants: For acute exacerbations

Pneumoconiosis / じん肺

• Overview
  • Fibroproliferative lung disease caused by inhalation of dust particles
  • Common in patients with history of long-term dust inhalation
• Presentation
  • Dry cough, dyspnea, fine crackles: Progressive lung fibrosis
• Examination
  • [PFT] %VC↓, DLCO↓: Restrictive ventilatory disorder and diffusion impairment
  • [X-ray, CT] Diffuse or merged nodular shadows: Silicosis
  • [X-ray, CT] Reticular shadows, pleural plaques: Asbestosis
  • [Pathology] Silicotic nodules: Silicosis
  • [Pathology] Asbestos bodies: Asbestosis
• Management
  • Antitussives, expectorants: Symptomatic treatment
  • Smoking cessation, respiratory rehabilitation: Preservation of remaining lung function

Radiation Pneumonitis / 放射線肺炎

• Overview
  • Interstitial lung disease caused by radiation therapy
  • Common complication of chest radiation for lung or breast cancer
• Presentation
  • Dry cough, dyspnea: Focal lung fibrosis
• Examination
  • [CT] Infiltrates corresponding to radiation field: Characteristic radiation-induced changes
• Management
  • Supportive care: For mild cases
  • Corticosteroids: For severe cases

Drug-induced Lung Injury / 薬剤性肺障害

• Overview
  • Interstitial lung disease caused by drugs
  • Causative drugs include chemotherapy or immunosuppressive drugs
• Presentation
  • Dry cough, dyspnea: Lung fibrosis
• Examination
  • [CT] Infiltrates, irregular shadows: Interstitial pneumonitis and fibrosis
• Management
  • Discontinuation of suspected drug: Primary treatment
  • Corticosteroids: For severe cases

Pulmonary Langerhans Cell Histiocytosis / 肺Langerhans細胞組織球症

• Overview
  • Proliferation and infiltration of Langerhans cells in lungs
  • Common 20-40s smokers
• Presentation
  • Asymptomatic: 10-20% cases
  • Dry cough, exertional dyspnea, sputum: Lung infiltration
  • Chest pain, pneumothorax: Cyst rupture
• Examination
  • [CT] Multiple nodules and cysts: Disease progression pattern
  • [Pathology] Langerhans cell infiltration with eosinophils: Diagnostic finding
• Management
  • Smoking cessation: Primary treatment for smokers
  • Corticosteroids: For progressive or symptomatic cases

Obstructive Lung Disease / 閉塞性肺疾患

Bronchial Asthma / 気管支喘息

• Overview
  • Chronic airway inflammation causing variable obstructive ventilatory impairment
• Presentation
  • Recurrent dyspnea, wheezing, cough (often nocturnal or early morning): Bronchial narrowing
• Examination
  • [Auscultation] Wheezes: High-pitched sounds from narrowed airways
  • [Spirometry] Decreased FEV1 and FEV1%, obstructive pattern on flow-volume curve: Airway obstruction
  • [Bronchial test] FEV1 increase after β2-agonist, FEV1 decrease after bronchoconstrictor: Airflow limitation reversibility
  • [Blood, Sputum] Eosinophils↑, ECP↑: Eosinophilic inflammation
• Management
  • [Long-term control] Inhaled corticosteroids (ICS), leukotriene receptor antagonists (LTRA), sustained-release theophylline (SRT), long-acting β2-agonists (LABA) , long-acting muscarinic antagonists (LAMA): Suppress airway inflammation and bronchodilation
  • [Long-term control] Bronchial thermoplasty: Reduce bronchial smooth muscle
  • [Acute exacerbation] Short-acting β2-agonists (SABA), systemic steroids, aminophylline, epinephrine, short-acting muscarinic antagonists (SAMA): Rapid bronchodilation
  • [Acute exacerbation] Oxygen therapy, intubation: For life-threatening cases

Aspirin-Exacerbated Respiratory Disease / アスピリン喘息

• Overview
  • Asthma triggered by NSAIDs with COX-1 inhibitory action
  • Common in non-atopic refractory asthma
• Presentation
  • Nasal congestion, dyspnea, wheezing, cough after NSAIDs intake: Bronchial constriction triggered by COX-1 inhibition
  • Chronic rhinosinusitis with nasal polyps: Associated upper airway inflammation
• Examination
  • [Spirometry] Decreased FEV1, reversible airway obstruction: Confirms asthma
• Management
  • Inhaled β2 agonists, IV aminophylline, SC epinephrine: Rapid bronchodilation
  • Intubation, oxygen, mechanical ventilation: For life-threatening cases

Chronic Obstructive Pulmonary Disease / 慢性閉塞性肺疾患

• Overview
  • Irreversible airflow limitation due to long-term exposure to harmful substances mainly tobacco
  • Common in smokers >40s
• Presentation
  • Chronic cough, sputum production, exertional dyspnea: Airway inflammation and obstruction
• Examination
  • [Spirometry] Post-bronchodilator FEV1% < 70%: Irreversible obstructive ventilatory impairment
  • [Chest X-ray, CT] Hyperinflation, emphysematous changes: Air trapping and tissue destruction
• Management
  • [Stable] Smoking cessation, vaccinations, pulmonary rehabilitation: Conservative treatment
  • [Stable] Bronchodilators (anticholinergics, β2-agonists, methylxanthines), inhaled steroids: Reduce airway obstruction
  • [Exacerbation] Antibiotics, bronchodilators, corticosteroids: Treat infection and inflammation
  • [Exacerbation] Oxygen therapy, ventilation support: Manage respiratory failure

Diffuse Panbronchiolitis / びまん性汎細気管支炎

• Overview
  • Chronic inflammation of respiratory bronchioles in both lungs
  • Common in patients with chronic sinusitis, associated with HLA-B54
• Presentation
  • Chronic purulent sputum, cough, exertional dyspnea: Airway inflammation and obstruction
  • Coarse crackles: Sputum retention in airways
• Examination
  • [Chest X-ray] Diffuse nodular shadows, hyperinflation: Bronchiolar inflammation and remodeling
  • [Chest CT] Centrilobular nodules, bronchiectasis: Bronchiolar inflammation and remodeling
  • [Spirometry] FEV1% < 70%: Obstructive ventilatory impairment
• Management
  • Low-dose long-term erythromycin: Immunomodulatory effects

Lung Tumor / 肺腫瘍

Pulmonary Hamartoma / 肺過誤腫

• Overview
  • Benign tumor with abnormal proliferation of normal lung tissue components
• Presentation
  • Asymptomatic: Incidental finding
  • Obstructive pneumonia: Due to bronchial obstruction
• Examination
  • [CT] Well-defined shadow, popcorn-like calcification: Characteristic radiological finding
  • [Biopsy] Mixed mesenchymal and epithelial components: Hamartoma nature
• Management
  • Observation: For asymptomatic cases
  • Surgical resection: Rule out malignancy

Squamous Cell Carcinoma / 扁平上皮癌

• Overview
  • Type of non-small cell lung cancer showing keratinization and intercellular bridges
  • Common in males over 50 with smoking history
• Presentation
  • Cough, sputum, hemoptysis: Due to bronchial invasion
  • Clubbing: Paraneoplastic manifestation
  • Hypercalcemia: Due to PTHrP production
• Examination
  • [Chest X-ray, CT] Mass shadow, atelectasis: Due to airway obstruction
  • [Sputum cytology] Orange-stained cells on Papanicolaou stain: Shows keratinized cancer cells
  • [Blood] Elevated SCC antigen, CYFRA, CEA: Tumor markers
  • [Biopsy] Keratinization, intercellular bridges: Diagnostic features
• Management
  • Surgery + adjuvant chemotherapy: Stage IA-IIIA
  • Radiation therapy alone: Stage I-III (inoperable)
  • Chemoradiotherapy: Stage IIIB-IIIC
  • Systemic therapy: Stage III (inoperable), Stage IV (metastatic)

Adenocarcinoma / 腺癌

• Overview
  • Type of non-small cell lung cancer showing glandular differentiation
  • Common in both genders including non-smokers
• Presentation
  • Asymptomatic: Peripheral location of tumor
  • Chest pain, cough, sputum: Due to tumor growth and invasion
• Examination
  • [Chest X-ray, CT] Spicula, vessel convergence, pleural indentation: Due to fibrosis and contraction of tumor
  • [Sputum cytology] Clusters of abnormal cells: Shows adenocarcinoma cells
  • [Blood] Elevated CEA, SLX: Tumor markers
  • [Biopsy] Glandular differentiation, mucin production: Diagnostic features
• Management
  • Surgery + adjuvant chemotherapy: Stage IA-IIIA
  • Radiation therapy alone: Stage I-III (inoperable)
  • Chemoradiotherapy: Stage IIIB-IIIC
  • Systemic therapy: Stage III (inoperable), Stage IV (metastatic)

Small Cell Lung Cancer / 小細胞肺癌

• Overview
  • Malignant neuroendocrine tumor with small cancer cells, rapid progression and poor prognosis
  • Common in male with smoking history
• Presentation
  • Cough, sputum, hemoptysis: Due to bronchial invasion
  • SIADH, Cushing syndrome, Lambert-Eaton syndrome: Paraneoplastic syndromes due to hormone production
• Examination
  • [Chest X-ray, CT] Hilar mass, lymphadenopathy: Central location with lymph node metastasis
  • [Sputum cytology] Small cells with scant cytoplasm: Characteristic appearance
  • [Blood] Elevated NSE, Pro-GRP: Tumor markers
  • [Biopsy] Small undifferentiated cells, neuroendocrine markers: Diagnostic features
• Management
  • Chemoradiotherapy: Limited Disease
  • Systemic therapy: Extensive Disease
  • Prophylactic cranial irradiation: Prevent brain metastasis

Metastatic Lung Tumor / 転移性肺腫瘍

• Overview
  • Malignant tumors from other organs metastasizing to lungs
• Presentation
  • Symptoms of primary tumor: Varies by origin
• Examination
  • [Chest X-ray, CT] Single or multiple nodules: Various radiological patterns
  • [Biopsy] Histology matching primary tumor: Confirms diagnosis and origin
• Management
  • Systemic therapy: Based on primary tumor sensitivity
  • Radiation therapy: For symptom palliation
  • Surgery: Selected cases with controlled primary and resectable metastases

Circulatory Disorder / 循環障害

Idiopathic Pulmonary Arterial Hypertension / 特発性肺動脈性肺高血圧症

• Overview
  • Elevated pulmonary arterial pressure due to narrowing of small pulmonary arteries without identifiable cause
  • Common in women aged 20-40s
• Presentation
  • Exertional dyspnea, fatigue, chest pain, cyanosis, syncope: Reduced pulmonary blood flow and cardiac output
  • Jugular vein distention, leg edema, hepatomegaly: Right heart failure
• Examination
  • [Physical] Accentuated P2, Graham Steell murmur: Pulmonary hypertension
  • [ECG] Right axis deviation, right ventricular hypertrophy, P pulmonale: Right heart strain
  • [Chest X-ray, CT] Enlarged pulmonary trunk, right heart enlargement: Pulmonary hypertension
  • [Echocardiogram] Right heart dilation, septal flattening: Right ventricular pressure overload
  • [Right heart catheterization] PAP ≥25mmHg, PAWP ≤15mmHg: Confirms diagnosis
• Management
  • Prostacyclin derivatives, endothelin antagonists, PDE5 inhibitors, continuous IV prostacyclin: Relax pulmonary arteries
  • Anticoagulation: Prevent thrombosis
  • Oxygen therapy, diuretics: For right heart failure
  • Lung transplantation: For refractory cases

Cardiogenic Pulmonary Edema / 心原性肺水腫

• Overview
  • Pulmonary edema due to left heart failure
  • Common causes: Myocardial infarction, valvular disease, cardiomyopathy, hypertensive heart disease
• Presentation
  • Exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, cyanosis, pink frothy sputum: Pulmonary congestion due to left heart failure
• Examination
  • [Physical] Bilateral coarse crackles: Fluid in alveoli
  • [Blood gas] PaO2↓, PaCO2↓: Type I respiratory failure
  • [Blood] BNP↑: Heart failure
  • [Chest X-ray] Enlarged cardiac silhouette, butterfly shadow, Kerley lines, vanishing tumor: Pulmonary edema
  • [Echocardiogram] Left ventricular enlargement, reduced wall motion: Left heart failure
• Management
  • Oxygen therapy: Treat hypoxemia
  • Diuretics, inotropes, vasodilators, morphine: Treat heart failure

Acute Respiratory Distress Syndrome / 急性呼吸窮迫症候群

• Overview
  • Acute onset of increased permeability pulmonary edema with severe hypoxemia
  • Common causes: Sepsis, trauma, severe burns, pneumonia, aspiration
• Presentation
  • Rapidly progressive dyspnea, tachypnea, cyanosis: Acute respiratory failure
• Examination
  • [Physical] Bilateral coarse crackles: Pulmonary edema
  • [Blood gas] PaO2↓, PaCO2↓, A-aDO2↑: Type I respiratory failure
  • [Chest X-ray] Bilateral infiltrates: Pulmonary edema
  • [Echocardiogram] Normal cardiac function: Rules out cardiogenic pulmonary edema
• Management
  • Oxygen therapy, mechanical ventilation: Treat hypoxemia
  • Antibiotics, diuretics: Treat sepsis/pneumonia, prevent fluid overload

Acute Pulmonary Thromboembolism / 急性肺血栓塞栓症

• Overview
  • Acute blockage of pulmonary arteries by blood clots from deep vein thrombosis
  • Common after surgery, prolonged bed rest, long flights
• Presentation
  • Sudden dyspnea, tachypnea, chest pain: Acute pulmonary arterial obstruction
• Examination
  • [Blood gas] PaO2↓, PaCO2↓, A-aDO2↑: Type I respiratory failure
  • [Blood] D-dimer↑, FDP↑: Evidence of thrombosis
  • [Chest X-ray] Enlarged cardiac silhouette, dilated pulmonary arteries: Pulmonary hypertension
  • [Echocardiogram] Right ventricular dilation and dysfunction: Right ventricular pressure overload
  • [Leg ultrasound] Deep vein thrombosis: Source of embolism
  • [Contrast CT] Filling defects in pulmonary arteries: Confirms diagnosis
• Management
  • Oxygen therapy: Treat hypoxemia
  • Heparin followed by warfarin/DOAC: Remove and prevent thrombosis
  • Thrombolysis, catheter thrombectomy: For severe or refractory cases

Chronic Thromboembolic Pulmonary Hypertension / 慢性血栓塞栓性肺高血圧症

• Overview
  • Pulmonary hypertension caused by organized thrombi in pulmonary arteries
• Presentation
  • Exertional dyspnea: Reduced pulmonary blood flow
  • Leg edema: Right heart failure
• Examination
  • [Right heart catheterization] Elevated pulmonary arterial pressure: Confirms pulmonary hypertension
  • [V/Q scan] Mismatched perfusion defects: Characteristic finding
• Management
  • Pulmonary endarterectomy: Remove thrombi
  • Balloon pulmonary angioplasty, pulmonary vasodilators: Relax pulmonary arteries
  • Lung transplantation: For severe cases

Pulmonary Arteriovenous Fistula / 肺動静脈瘻

• Overview
  • Vascular malformation with direct shunt between pulmonary artery and vein
• Presentation
  • Exertional dyspnea, cyanosis, clubbing: Reduced gas exchange efficiency
  • Polycythemia (RBC↑, Hb↑, Ht↑): Compensatory response to chronic hypoxemia
• Examination
  • [Blood gas] PaO2↓: Type I respiratory failure
  • [Chest X-ray] Well-defined nodular shadow: Vascular malformation
  • [Contrast CT] Homogeneously enhanced nodule: Diagnostic finding
• Management
  • Transcatheter embolization: Treat fistula
  • Surgical resection: Alternative option

Functional Disorder / 機能障害

Obstructive Sleep Apnea Syndrome / 閉塞性睡眠時無呼吸症候群

• Overview
  • Recurrent upper airway obstruction during sleep leading to apnea or hypopnea
  • Common in middle-aged obese men and postmenopausal women
• Presentation
  • Snoring, breathing pauses during sleep: Upper airway obstruction
  • Daytime sleepiness, reduced concentration: Sleep fragmentation
• Examination
  • [Polysomnography] Obstructive apnea, AHI ≥5: Confirms diagnosis
• Management
  • Weight reduction: Lifestyle modification
  • Nasal CPAP: Maintains airway patency

Hyperventilation Syndrome / 過換気症候群

• Overview
  • Episodic hyperventilation triggered by psychological factors
  • Common in young women
• Presentation
  • Tachypnea, dyspnea, palpitations, chest pain: Triggered by stress or anxiety
  • Dizziness, altered consciousness, numbness, spasm: Respiratory alkalosis and hypocalcemia
• Examination
  • [Blood gas] PaCO2↓, pH↑: Respiratory alkalosis
• Management
  • Calm patient, guide slow breathing: Normalize respiratory rate

CO2 Narcosis / CO2ナルコーシス

• Overview
  • Severe accumulation of CO2 leading to central nervous system dysfunction
• Presentation
  • Drowsiness, confusion, coma: High CO2 levels affecting brain function
  • Decreased respiratory rate: Respiratory center depression
• Examination
  • [Blood gas] PaCO2↑, HCO3-↑: Severe CO2 retention
• Management
  • Reduce O2 concentration: High-concentration O2 suppress respiration
  • NPPV, intubation: For persistent hypoxemia

Pleural Disorder / 胸膜疾患

Pleuritis / 胸膜炎

• Overview
  • Inflammation of pleura due to malignancy or infection
• Presentation
  • Chest pain (worsening with deep breathing or coughing), dyspnea: Inflammation of pleural membrane
  • Cough, fever: Underlying infection or inflammation
• Examination
  • [Physical] Dullness to percussion, pleural friction rub, decreased breath sounds, egophony: Pleural effusion
  • [Chest X-ray] Blunting of costophrenic angle, band-like opacity: Pleural effusion
  • [Pleural fluid] Exudative effusion: Identify malignant, tuberculous, or parapneumonic causes
• Management
  • Treat underlying cause: Primary management
  • Thoracentesis, chest tube drainage: Remove pleural fluid

Empyema / 膿胸

• Overview
  • Collection of purulent fluid in pleural space due to infection, classified into acute or chronic forms
• Presentation
  • Chest pain, dyspnea, fever: Infection and inflammation of pleural space
• Examination
  • [Chest X-ray] Pleural opacity, possible air-fluid level: Purulent effusion
  • [Pleural fluid] Purulent fluid, bacterial culture positive: Confirms diagnosis
• Management
  • [Acute] Antibiotics, chest tube drainage: Treat infection and remove pus
  • [Chronic] Decortication: Remove thickened pleura

Spontaneous Pneumothorax / 自然気胸

• Overview
  • Air in pleural space without obvious cause
  • Common in males (20s, tall, thin) and patients with underlying lung diseases (COPD, interstitial pneumonia, tuberculosis)
• Presentation
  • Sudden onset dyspnea, chest pain: Lung collapse due to air entrance
• Examination
  • [Physical] Hyperresonance to percussion, decreased breath sounds: Air in pleural space
  • [Chest X-ray] Transparency without lung markings, collapsed lung: Pneumothorax with lung collapse
• Management
  • Observation, needle aspiration: For small pneumothorax
  • Chest tube drainage: For larger pneumothorax

Tension Pneumothorax / 緊張性気胸

• Overview
  • Air continuously enters pleural space, medical emergency due to rapid respiratory and circulatory deterioration
  • Occurs in spontaneous pneumothorax, chest trauma, or mechanical ventilation
• Presentation
  • Chest pain, dry cough, tachypnea, dyspnea, cyanosis: Ventilation impairment
  • Sudden hypotension, tachycardia, jugular vein distention: Circulatory shock due to mediastinal compression
• Examination
  • [Physical] Hyperresonance to percussion, decreased breath sounds: Air in pleural space
  • [Chest X-ray] Severe lung collapse, mediastinal shift to opposite side, depressed hemidiaphragm: High pressure pneumothorax
• Management
  • Immediate needle decompression, chest tube drainage: Emergent treatment

Pleural Mesothelioma / 胸膜中皮腫

• Overview
  • Malignant tumor arising from pleural mesothelial cells
  • Strong association with asbestos exposure, 20-40 years latency period
• Presentation
  • Chest pain, exertional dyspnea: Tumor invasion and pleural effusion
• Examination
  • [Chest X-ray, CT] Pleural masses, irregular pleural thickening, pleural effusion: Tumor invasion and pleural effusion
  • [Pleural fluid] Elevated hyaluronic acid: Characteristic finding
  • [Biopsy] Pleural malignant cells: Confirm diagnosis
• Management
  • Extrapleural pneumonectomy, pleurectomy: For resectable cases
  • Chemotherapy, radiation therapy: Combined or palliative treatment

Mediastinal Disorder / 縦隔疾患

Mediastinitis / 縦隔炎

• Overview
  • Inflammation of mediastinum due to descending infection, trauma, or esophageal perforation
• Presentation
  • Fever, chest pain, dyspnea, neck swelling: Severe inflammation in mediastinum
• Examination
  • [Blood] WBC↑, CRP↑: Active inflammation
  • [Chest X-ray] Widened mediastinum: Inflammatory changes and edema
• Management
  • Antibiotics, drainage: Control infection

Thymoma / 胸腺腫

• Overview
  • Mediastinal tumor arising from thymic epithelial cells, commonly in anterior mediastinum
• Common in adults over 40s
• Presentation
  • Asymptomatic, chest pressure, dyspnea, cough: Mass effect in mediastinum
  • Muscle weakness, ptosis, diplopia: Associated myasthenia gravis
• Examination
  • [Chest X-ray, CT, MRI] Mass in anterior mediastinum: Evaluate tumor extent and characteristics
  • [Biopsy] Proliferation of epithelial cells and lymphocytes: Confirm diagnosis
• Management
  • Thymectomy, radiation therapy: Complete resection
  • Chemotherapy: For metastatic cases

Germ Cell Tumor / 胚細胞性腫瘍

• Overview
  • Mediastinal tumor derived from primitive germ cells, commonly in anterior mediastinum
  • Common in young adults
• Presentation
  • Asymptomatic, chest pain, dyspnea: Mass effect in mediastinum
• Examination
  • [Chest X-ray, CT, MRI] Mass in anterior mediastinum: Evaluate tumor extent and characteristics
  • [Biopsy] Teratoma, seminoma, nonseminoma: Confirm diagnosis
• Management
  • [Mature teratoma] Surgery: Complete resection
  • [Seminoma, non-seminoma] Chemotherapy, combined with other therapies: Multimodal therapy

Neurogenic Tumor / 神経原性腫瘍

• Overview
  • Mediastinal tumor derived from peripheral nerve tissues, commonly in posterior mediastinum
• Presentation
  • Asymptomatic, Horner’s syndrome: Tumor compressing adjacent nerves
• Examination
  • [Chest X-ray, CT, MRI] Mass in posterior mediastinum: Evaluate tumor extent and characteristics
  • [Pathology] Diagnosis after resection: Difficult location for biopsy
• Management
  • Surgical resection: Complete resection

Miscellaneous Respiratory Disorder / その他の呼吸器疾患

Bronchiectasis / 気管支拡張症

• Overview
  • Irreversible dilation of peripheral airways due to recurrent infection or inflammation
• Presentation
  • Chronic cough, substantial sputum, hemoptysis, recurrent fever: Chronic airway infection
• Examination
  • [Physical] Coarse crackles: Airway secretions
  • [Chest X-ray] Tram lines: Thickened bronchial walls
  • [Chest CT] Dilated bronchi: Confirms diagnosis
• Management
  • Postural drainage, respiratory rehabilitation, expectorants: Remove airway secretions
  • Long-term low-dose macrolide: Anti-inflammatory effect
  • Hemostatic drugs, bronchoscopic hemostasis, bronchial artery embolization: Treat hemoptysis
  • Antibiotics: Treat secondary bacterial infection during acute exacerbation

Pulmonary Sequestration / 肺分画症

• Overview
  • Abnormal lung tissue receiving blood supply directly from aorta without normal airway connection, classified as intralobar or extralobar
  • Common in young adults (intralobar) and infants (extralobar)
• Presentation
  • [Intralobar] Cough, sputum, fever: Recurrent infection
  • [Extralobar] Dyspnea, cyanosis: Developmental abnormality
• Examination
  • [Chest X-ray] Mass or cystic shadow in left lower lung: Abnormal lung tissue
  • [CTA, MRA] Aberrant artery from descending aorta: Diagnostic finding
• Management
  • Surgical resection: Prevent infection

Pulmonary Cyst Disease / 肺囊胞症

• Overview
  • Formation of sac-like structures in lungs, including bullae/blebs (air-filled) and bronchogenic cysts (mucus-filled)
• Presentation
  • [Bullae/Blebs] Asymptomatic, occasionally pneumothorax: Rupture of subpleural bullae/blebs
  • [Bronchogenic cysts] Asymptomatic, occasionally dyspnea: Airway compression
• Examination
  • [Bullae/Blebs, CT] Air-filled spaces in subpleural region: Confirm bullae/blebs
  • [Bronchogenic cysts, CT] Mucus-filled cyst in middle mediastinum: Confirm bronchogenic cysts
• Management
  • [Bullae/Blebs] Surgical resection: For recurrent pneumothorax
  • [Bronchogenic cysts] Surgical resection: For symptomatic cases

Autoimmune Pulmonary Alveolar Proteinosis / 自己免疫性肺胞蛋白症

• Overview
  • Abnormal accumulation of surfactant-derived lipoprotein in alveoli and terminal bronchioles, mostly associated with anti-GM-CSF antibodies
  • Common in 30-50s smoking males
• Presentation
  • Cough, exertional dyspnea: Accumulation of surfactant material
• Examination
  • [Blood] LDH↑, KL-6↑, CEA↑, SP-A↑, SP-D↑: Markers of alveolar damage and surfactant accumulation
  • [Chest X-ray] Bilateral ground-glass opacities: Surfactant accumulation
  • [CT] Crazy-paving pattern: Combined ground-glass and septal thickening
  • [BAL] Milky-white lavage fluid: Surfactant accumulation
  • [Blood] Anti-GM-CSF antibody positive: Confirms autoimmune nature
• Management
  • Whole lung or segmental lavage: Remove accumulated material

Lymphangioleiomyomatosis / リンパ脈管筋腫症

• Overview
  • Proliferation of smooth muscle-like cells (LAM cells) in lungs, kidneys, and lymphatics, associated with tuberous sclerosis
  • Common in 20-40s women
• Presentation
  • Exertional dyspnea, cough, bloody sputum: Lung destruction
  • Recurrent pneumothorax: Rupture of lung cysts
• Examination
  • [Blood] VEGF-D↑: Marker for LAM
  • [PFT] Diffusion impairment, obstructive pattern: Airway obstruction and parenchymal destruction
  • [Chest X-ray] Reticular shadows, hyperinflation: Formation of multiple cysts
  • [CT] Multiple thin-walled cysts: Characteristic finding
  • [Biopsy] LAM cell proliferation: Confirms diagnosis
• Management
  • Sirolimus (mTor inhibitors): Inhibit LAM cells proliferation
  • Bronchodilators: For obstructive symptoms
  • Surgery: For recurrent pneumothorax
  • Oxygen therapy, lung transplantation: For respiratory failure

Airway Foreign Bodies / 気道異物

• Overview
  • Foreign objects obstructing or narrowing airways
  • Common in children and elderly with history of aspiration
• Presentation
  • Cough, wheezing, dyspnea, cyanosis: Airway obstruction
• Examination
  • [Chest X-ray] Visible foreign body, Holzknecht sign: Identify foreign body
• Management
  • Heimlich maneuver: Immediate intervention for complete obstruction
  • Bronchoscopic removal: For accessible foreign bodies

Flail Chest / フレイルチェスト

• Overview
  • Multiple rib fractures cause chest wall segment to lose continuity
  • Commonly due to severe chest trauma
• Presentation
  • Paradoxical chest wall movement: Affected segment moves inward during inspiration, outward during expiration
• Examination
  • [Physical] Chest wall instability on palpation: Loss of normal thoracic cage rigidity
  • [Imaging] Multiple rib fractures: Confirms diagnosis
• Management
  • Chest tube drainage: For pneumothorax or hemothorax
  • Positive pressure ventilation: For respiratory failure
  • Analgesics: Pain control
  • Surgical fixation: For refractory cases

Gastroenterology / 消化器科

Esophagus Disorder / 食道疾患

Esophageal Achalasia / 食道アカラシア

• Overview
  • Functional disease due to degeneration of Auerbach’s plexus in lower esophageal muscle layer
  • Common in 20-60s adults
• Presentation
  • Dysphagia, chest pain, food regurgitation: Impaired esophageal peristalsis and lower esophageal sphincter relaxation
• Examination
  • [Barium swallow] Beak-like narrowing of lower esophagus, dilated proximal esophagus: Impaired LES relaxation and esophageal motility
  • [Endoscopy] Fluid/food retention, dilated esophagus, wrap-around at cardia: Impaired esophageal emptying
  • [Manometry] Elevated LES pressure, absent esophageal peristalsis: Confirms diagnosis
• Management
  • Calcium channel blockers, nitrates: Relax LES
  • Balloon dilation: Extend LES
  • Per-Oral Endoscopic Myotomy (POEM), Heller-Dor procedure: Endoscopic or laparoscopic myotomy

Mallory-Weiss Syndrome / Mallory-Weiss症候群

• Overview
  • Mucosal tear at gastroesophageal junction due to sudden increase in intra-abdominal pressure (vomiting)
  • Common causes: Excessive alcohol intake, hyperemesis gravidarum, chemotherapy, endoscopy
• Presentation
  • Hematemesis after forceful vomiting: Bleeding from mucosal tear
• Examination
  • [Endoscopy] Longitudinal mucosal tear at gastroesophageal junction: Confirms diagnosis
• Management
  • Conservative treatment (NPO, IV fluids, hemostatic drugs): If bleeding stopped
  • Endoscopic hemostasis (clipping, hemostatic forceps, injection therapy): If active bleeding

Spontaneous Esophageal Rupture / 特発性食道破裂

• Overview
  • Full-thickness rupture of esophageal wall due to sudden increase in intra-abdominal pressure (vomiting)
• Presentation
  • Severe chest pain, dyspnea, shock: Full-thickness rupture with mediastinal involvement
• Examination
  • [X-ray, CT] Pleural effusion, mediastinal emphysema, pneumothorax: Air and fluid in mediastinum
  • [Contrast CT] Contrast leakage into mediastinum: Confirm diagnosis
• Management
  • Emergency surgery: Surgical closure and drainage

Esophageal Hiatal Hernia / 食道裂孔ヘルニア

• Overview
  • Protrusion of stomach through esophageal hiatus into mediastinum
  • Common in obese middle-aged men and elderly women
• Presentation
  • Heartburn, chest pain, epigastric pain, dysphagia: Due to associated GERD
• Examination
  • [Barium swallow] Protrusion of stomach into mediastinum: Confirm diagnosis
  • [Endoscopy] Gastric mucosa extending above diaphragm: Confirm diagnosis
• Management
  • Observation: For asymptomatic cases
  • Weight loss, elevation of upper body during sleep, acid suppressants: For GERD cases
  • Surgical repair (Nissen fundoplication): For incarceration cases

Gastroesophageal Reflux Disease / 胃食道逆流症

• Overview
  • Reflux of gastric contents into esophagus causing symptoms, risk factor for Barrett’s esophagus and adenocarcinoma
• Presentation
  • Heartburn, acid regurgitation (worse after meals, at night, bending forward): Typical symptoms from acid reflux
  • Chest pain, cough, wheezing, throat discomfort, ear pain, hoarseness: Extra-esophageal symptoms
• Examination
  • [Endoscopy] Mucosal redness, erosions, ulcers: Erosive GERD
  • [Endoscopy, 24h pH monitoring] No visible lesions + abnormal acid exposure: Non-erosive GERD (NERD)
• Management
  • Lifestyle modifications: Avoid late meals, elevate head of bed, weight loss, discontinue causative drugs
  • PPI/P-CAB, H2RAs, antacids, prokinetics: Reduce acid secretion, improve gastric motility
  • Endoscopic or surgical treatment (Nissen fundoplication): For refractory cases

Esophageal Cancer / 食道癌

• Overview
  • Malignant epithelial tumor of esophagus, mainly squamous cell carcinoma but also adenocarcinoma
  • Common in 60-70s men, risk factors include alcohol, smoking, achalasia, Barrett’s esophagus (adenocarcinoma)
• Presentation
  • [Early] Asymptomatic, mild burning sensation during swallowing: Early mucosal changes
  • [Advanced] Dysphagia, weight loss, chest discomfort, hoarseness, cough: Local invasion and obstruction
• Examination
  • [Endoscopy] Subtle redness, elevation/depression, iodine-unstained areas, brownish areas on NBI: Mucosal changes in early stage
  • [Endoscopy] Irregular ulcers, masses, strictures: Tumor growth in advanced stage
• Management
  • [Stage 0] EMR, ESD: Remove early mucosal lesions
  • [Stage I-III] Surgery, lymph node dissection, reconstruction: Curative resection
  • [Stage IV] Chemotherapy (5-FU + cisplatin), radiation: For unresectable cases
  • [Palliative] Stenting, bypass surgery, gastrostomy: Relieve obstruction and fistulas

Esophagogastric Varices / 食道・胃静脈瘤

• Overview
  • Dilated submucosal veins in esophagus and stomach due to portal hypertension, asymptomatic but life-threatening if ruptured
  • Common in liver cirrhosis
• Presentation
  • Asymptomatic: Found during screening
• Examination
  • [Endoscopy, esophagogram] Dilated submucosal veins: Assess risk of bleeding
  • [Contrast CT] Dilated vessels in esophagus and stomach: Confirm diagnosis and extent
• Management
  • [Endoscopic] Endoscopic injection sclerotherapy (EIS), endoscopic variceal ligation (EVL): First choice for esophageal varices
  • [Interventional] B-RTO, TIPS: For gastric varices resistant to endoscopic treatment
  • [Medical] β-blockers, nitrates: Prevent bleeding and recurrence
  • [Surgical] Hassab operation, esophageal transection: Less common

Rupture of Esophagogastric Varices / 食道・胃静脈瘤破裂

• Overview
  • Life-threatening bleeding from esophagogastric varices
• Presentation
  • Sudden hematemesis, melena: Massive bleeding from ruptured varices
  • Shock: Blood loss leading to circulatory failure
• Examination
  • [Physical] Vital signs: Assess severity
• Management
  • [Initial] IV fluids, blood transfusion: Stabilize hemodynamics
  • [Endoscopic] Endoscopic variceal ligation (EVL), cyanoacrylate injection (CA): Hemostasis of esophageal or gastric bleeding
  • [Temporary] Balloon tamponade (SB tube): Hemostasis when endoscopic treatment fails
  • [Medical] Vasopressin, nitroglycerin: Reduce portal pressure

Stomach Disorder / 胃疾患

Functional Dyspepsia / 機能性ディスペプシア

• Overview
  • Functional gastrointestinal disorder without organic, systemic, or metabolic causes, associated with stress
• Presentation
  • Postprandial fullness, early satiety: Postprandial distress syndrome
  • Epigastric pain, burning: Epigastric pain syndrome
• Examination
  • [Endoscopy, blood tests] Normal: Rules out organic or systemic disease
• Management
  • Patient education, lifestyle modification, cognitive behavior therapy: Stress management, regular meals
  • Prokinetics (acotiamide), acid suppressants: Improve gastric motility, reduce acid secretion

Acute Gastric Mucosal Lesion / 急性胃粘膜病変

• Overview
  • Acute epigastric pain with multiple erosions and bleeding in gastric mucosa
  • Causes: NSAIDs, alcohol, stress, H. pylori, Anisakis infection
• Presentation
  • Sudden epigastric pain, nausea, vomiting, hematemesis: Acute mucosal inflammation
• Examination
  • [Endoscopy] Multiple erosions, ulcers, edema, bleeding in gastric mucosa: Acute mucosal damage
• Management
  • Remove causative factors: Stop NSAIDs, remove Anisakis
  • Acid suppressants (PPI, H2-receptor antagonist): Reduce acid secretion
  • Endoscopic hemostasis (clipping, injection therapy): For bleeding cases

H. pylori Gastritis / H. pylori感染胃炎

• Overview
  • Chronic gastritis caused by H. pylori infection, may progress to intestinal metaplasia and gastric cancer
• Presentation
  • Epigastric pain, bloating, nausea, vomiting, loss of appetite: Chronic gastritis
• Examination
  • [Endoscopy] Atrophic changes, diffuse redness, enlarged folds: Chronic inflammation
  • [Endoscopy] Nodular gastritis, xanthoma, intestinal metaplasia: Advanced changes
  • [H. pylori tests] Rapid urease test, urea breath test: Detect active infection
  • [Biopsy] Inflammatory cell infiltration, atrophic changes: Histological confirmation
• Management
  • PPI/P-CAB + Amoxicillin + Clarithromycin (or metronidazole): Eradication of H. pylori

Gastroduodenal Ulcer / 胃・十二指腸潰瘍

• Overview
  • Deep mucosal defect extending beyond muscularis mucosae
  • Causes: H. pylori infection, NSAIDs use
• Presentation
  • Epigastric pain, bloating, nausea, vomiting, loss of appetite: Chronic mucosal damage
  • Coffee-ground vomiting, melena, anemia, shock (severe cases): Gastrointestinal bleeding
• Examination
  • [Endoscopy] Smooth-edged ulcer: Direct visualization of ulcer
  • [Upper GI series] Niche sign, converging folds: Radiological signs of ulcer
• Management
  • H. pylori eradication, discontinue NSAIDs: Remove underlying cause
  • PPI/P-CAB, H2-blockers, mucosal protective agents, anticholinergics: Acid suppression, enhance mucosal defense
  • [Bleeding] Stabilize vital signs (if shock) , endoscopic hemostasis (clipping, injection therapy): Emergent hemostasis
  • [Stenosis] Endoscopic balloon dilation, surgery: Resolve stenosis

Perforated Gastroduodenal Ulcer / 胃・十二指腸潰瘍穿孔

• Overview
  • Deep ulcer penetrating through stomach/duodenal wall into peritoneal cavity, leads to peritonitis and requires urgent treatment
  • Common in patients with gastroduodenal ulcer history
• Presentation
  • Sudden severe epigastric pain, muscle guarding, rebound tenderness: Peritoneal irritation from gastric contents
  • Decreased bowel sounds, loss of liver dullness: Paralytic ileus, free air
• Examination
  • [Chest/Abdominal X-ray] Free air under diaphragm: Perforation sign
  • [CT] Free air around liver surface: Perforation sign
• Management
  • [Mild] NPO, IV fluids, antibiotics, acid suppression, nasogastric tube: Conservative treatment
  • [Severe] Laparoscopic surgery (peritoneal lavage and drainage, perforation repair, omental patch): Repair surgery

Gastric Polyps / 胃ポリープ

• Overview
  • Localized mucosal protrusions into gastric lumen excluding tumors
  • Classified as fundic gland polyps (associated with PPI use) and hyperplastic polyps (associated with H. pylori)
• Presentation
  • Asymptomatic: Mostly
  • Anemia: Due to polyp bleeding
• Examination
  • [Endoscopy] Mucosal color polyp in fundic gland area: Fundic gland polyps
  • [Endoscopy] Reddish color polyp in atrophic mucosa: Hyperplastic polyps
• Management
  • Remove causative factors: Reduce PPI use, H. pylori eradication

Gastric Adenoma / 胃腺腫

• Overview
  • Benign epithelial tumor of stomach with risk of malignant transformation, associated with H. pylori infection
• Presentation
  • Asymptomatic: Mostly
  • Anemia: Due to bleeding
• Examination
  • [Endoscopy] Whitish elevated lesion with uniform granular surface: Differentiates from early gastric cancer
• Management
  • Endoscopic resection: For lesions showing growth or >2cm

Gastrointestinal Stromal Tumor / 消化管間質腫瘍

• Overview
  • Mesenchymal tumor from interstitial cells of Cajal, with c-kit gene mutation and KIT constitutive activation
  • Common in 50-60s
• Presentation
  • Asymptomatic: Mostly
  • Abdominal discomfort, pain, palpable mass: Tumor growth
  • Melena, anemia: Tumor bleeding
• Examination
  • [Endoscopy, GI series, EUS] Smooth submucosal elevation, bridging fold, delle: Submucosal tumor features
  • [Pathology] KIT(+), CD34(+), DOG1(+): Confirms Cajal cell origin
• Management
  • Surgical resection: Risk of malignant transformation
  • Imatinib, sunitinib, regorafenib: For unresectable or recurrent cases

Gastric Cancer / 胃癌

• Overview
  • Malignant tumor of gastric mucosa ,mostly adenocarcinoma
  • Risk factors: H. pylori infection, atrophic gastritis, high salt intake, smoking
• Presentation
  • Asymptomatic: Found during screening
  • Epigastric discomfort, weight loss, appetite loss, nausea: Tumor growth
  • Black stool, fatigue: Gastrointestinal bleeding
• Examination
  • [Endoscopy, Upper GI series, EUS] Irregular depressed lesions, converging folds: Early gastric cancer (≤submucosal invasion)
  • [Endoscopy, Upper GI series, EUS] Irregular ulcers with raised margins: Advanced gastric cancer (≥muscularis propria invasion)
• Management
  • [Early] EMR, ESD, partial gastrectomy + lymph node dissection: Endoscopic or limited surgery
  • [Advanced] Extended gastrectomy + lymph node dissection: Standard surgery
  • [Unresectable] S-1 + cisplatin, capecitabine + cisplatin + trastuzumab: Various combination of chemotherapy

Dumping Syndrome / ダンピング症候群

• Overview
  • Post-gastrectomy condition with food rapidly entering small intestine
  • Classified as early (within 30 min) and late (2-3 hours after meals)
• Presentation
  • [Early] Abdominal pain, diarrhea, nausea: Rapid intestinal distension
  • [Early] Palpitations, sweating, dizziness, syncope: Vasomotor symptoms
  • [Late] Palpitations, cold sweat, tremor, weakness: Reactive hypoglycemia
• Examination
  • Clinical
• Management
  • Dietary modification: Small frequent meals, high protein/fat and low carb diet
  • [Early] Antihistamines, antiserotonin drugs: Relieve vasomotor symptoms
  • [Late] α-glucosidase inhibitors: Prevent postprandial hyperglycemia

Intestine Disorder / 腸疾患

Irritable Bowel Syndrome / 過敏性腸症候群

• Overview
  • Functional gastrointestinal disorder with chronic abdominal symptoms, stress-related but exact cause unknown
  • Common disease in adults
• Presentation
  • Abdominal pain/discomfort, diarrhea, constipation: Chronic symptoms lasting several months
  • No alarm symptoms (fever, bloody stool, weight loss): Distinguishes from organic diseases
• Examination
  • [Endoscopy] Normal: Distinguishes from organic diseases
• Management
  • Patient education, lifestyle modification, relaxation, cognitive behavioral therapy: Benign nature of condition
  • Probiotics, polycarboxylate calcium, trimebutine: Improve gut function
  • Lubiprostone, linaclotide, mosapride: For constipation-predominant cases
  • Ramosetron, loperamide: For diarrhea-predominant cases

Simple Intestinal Obstruction / 単純性腸閉塞

• Overview
  • Mechanical bowel obstruction without vascular compromise
  • Most commonly due to postoperative adhesions, also due to colon cancer
• Presentation
  • Intermittent abdominal pain, distension, vomiting, absence of defecation: Gradual progression of obstruction
• Examination
  • [Physical] Increased bowel sounds, metallic sounds, tympanic sound, visible peristalsis: Signs of obstruction
  • [Blood] Hemoconcentration, metabolic alkalosis: Due to dehydration and vomiting
  • [X-ray] Dilated bowel loops, niveau: Gas and fluid accumulation in lumen
• Management
  • NPO, IV fluids: Correct dehydration and electrolyte imbalance
  • Nasogastric/ileus tube: Decompress bowel
  • Antibiotics: Prevent sepsis from bacterial overgrowth
  • Surgery: For resistant cases

Complex Intestinal Obstruction / 複雑性腸閉塞

• Overview
  • Mechanical bowel obstruction with vascular compromise
  • Causes include adhesions, intussusception, volvulus, incarcerated hernia
• Presentation
  • Sudden onset severe abdominal pain, vomiting, distension, shock: Rapid progression
• Examination
  • [Physical] Severe tenderness, decreased bowel sounds, muscle guarding, rebound tenderness: Peritoneal irritation
  • [Blood] Hemoconcentration, WBC↑, CK↑, LDH↑, metabolic acidosis: Indicates bowel necrosis
  • [X-ray] Gasless abdomen, niveau: Fluid accumulation in lumen
  • [Contrast CT] Severe bowel wall edema, poor enhancement, ascites: Confirms strangulation
• Management
  • IV fluids, antibiotics: Initial stabilization
  • Surgery (release strangulation, resect necrotic bowel): Emergency surgery

Paralytic Ileus / 麻痺性イレウス

• Overview
  • Functional ileus due to impaired intestinal nerve and muscle function
  • Causes include post-surgery, acute peritonitis, acute mesenteric artery occlusion, diabetes, medications
• Presentation
  • Minimal pain, abdominal distension: Due to intestinal paralysis
• Examination
  • [Physical] Decreased bowel sounds: Intestinal paralysis
  • [X-ray] Dilated bowel loops, air-fluid levels: Gas and fluid accumulation in lumen
• Management
  • Treat underlying cause: Primary treatment
  • Metoclopramide, neostigmine: Improve intestinal motility
  • Nasogastric/ileus tube: Decompress bowel

Superior Mesenteric Artery Syndrome / 上腸間膜動脈症候群

• Overview
  • Compression of horizontal part of duodenum between superior mesenteric artery and aorta/vertebrae
  • Common in thin females
• Presentation
  • Nausea, vomiting, loss of appetite, upper abdominal pain: Due to duodenal obstruction
• Examination
  • [Upper GI series] Dilated proximal duodenum, cutoff at SMA crossing: Duodenal compression
  • [CT] Narrow aortomesenteric angle: Confirms diagnosis
• Management
  • Weight gain, positional changes: Conservative treatment
  • Duodenojejunostomy: For resistant cases

Crohn’s Disease / Crohn病

• Overview
  • Granulomatous inflammatory disease with skip lesions affecting all layers of digestive tract wall
  • Common in 10-20s adults
• Presentation
  • Abdominal pain, diarrhea: Transmural inflammation of intestinal wall
  • Fever, weight loss: Systemic inflammation
  • Perianal abscess/fistula, oral aphthae, arthritis: Extra-intestinal manifestations
• Examination
  • [Blood] Anemia, WBC↑, CRP↑, ESR↑, hypoproteinemia: Chronic inflammation
  • [Endoscopy] Skip lesions, longitudinal ulcers, cobblestone appearance, strictures, fistulas: Non-continuous inflammation
  • [Biopsy] Non-caseating epithelioid granulomas: Chronic granulomatous inflammation
• Management
  • Nutritional therapy (enteral nutrition, TPN): Rest bowel and eliminate dietary allergens
  • Corticosteroids, 5-ASA (mesalazine, sulfasalazine): Anti-inflammatory drugs for remission induction
  • 5-ASA, biologics (anti-TNF-α, anti-IL-12/23, anti-integrin), immunomodulators (azathioprine, mercaptopurine): Anti-inflammatory drugs for remission maintenance
  • Surgery: For strictures, fistula, bleeding

Ulcerative Colitis / 潰瘍性大腸炎

• Overview
  • Diffuse inflammatory disease with continuous lesions affecting colonic mucosa
  • Common in 10-30s adults
• Presentation
  • Bloody diarrhea, abdominal pain, tenesmus: Mucosal inflammation and ulceration
  • Fever, weight loss: Systemic inflammation
• Examination
  • [Blood] Anemia, CRP↑, ESR↑, hypoproteinemia: Chronic inflammation
  • [Endoscopy] Continuous lesions, loss of vascular pattern, erosions/ulcers, pseudopolyps, loss of haustra: Continuous inflammation from rectum
  • [Biopsy] Diffuse inflammatory cell infiltration, crypt abscess, reduced goblet cells: Chronic mucosal inflammation
• Management
  • 5-ASA (mesalazine, sulfasalazine), corticosteroids, calcineurin inhibitors (tacrolimus, cyclosporine): Anti-inflammatory drugs for remission induction
  • 5-ASA, immunomodulators (azathioprine, mercaptopurine) , biologics (anti-TNF-α, anti-integrin), JAK inhibitors: Anti-inflammatory drugs for remission maintenance
  • Surgery (total colectomy): For refractory cases, cancer, toxic megacolon

Intestinal Tuberculosis / 腸結核

• Overview
  • Tuberculosis infection of intestinal tract causing ulcers and scarring
• Presentation
  • Abdominal pain, diarrhea, bloody stool: Intestinal inflammation and ulceration
  • Fever, weight loss: Systemic effects of TB infection
• Examination
  • [Endoscopy] Deformed ileocecal valve, ulcers: Characteristic TB changes
  • [Biopsy] Granulomas, caseous necrosis: Confirms TB infection
• Management
  • Anti-tuberculosis drugs: Standard TB treatment

Pseudomembranous Colitis / 偽膜性大腸炎

• Overview
  • Caused by Clostridioides difficile overgrowth after antibiotic use
  • Common in elderly and patients with underlying diseases
• Presentation
  • Watery diarrhea, abdominal pain, fever (after antibiotic use): CD toxin damage colonic mucosa
• Examination
  • [Blood] WBC↑, CRP↑: Inflammatory response
  • [Stool] CD toxin A/B positive, GDH antigen positive, culture positive: Confirms C. difficile infection
  • [Endoscopy] Multiple yellow-white pseudomembranes: Lesions due to CD toxin
• Management
  • Discontinue causative antibiotics: Primary intervention
  • Metronidazole, vancomycin: Treat C. difficile infection
  • Fidaxomicin, anti-toxin B antibody, fecal transplantation: For refractory cases

Ischemic Colitis / 虚血性大腸炎

• Overview
  • Small vessel ischemia leading to localized mucosal damage in colon
  • Common in elderly with atherosclerotic risk factors
• Presentation
  • Sudden left lower abdominal pain: Ischemia primarily affects left colon
  • Diarrhea, bloody stool: Mucosal damage and inflammation
• Examination
  • [Endoscopy] Mucosal edema, erosions, submucosal hemorrhage, longitudinal ulcers: Mucosal damage in left colon
  • [Barium enema] Thumb printing sign, longitudinal ulcers: Mucosal edema in left colon
• Management
  • Rest, fasting, fluid therapy: Conservative treatment
  • Balloon dilation, emergency surgery: For stricture or gangrenous type

Acute Mesenteric Artery Occlusion / 急性腸間膜動脈閉塞症

• Overview
  • Acute occlusion of mesenteric artery (mainly SMA) leading to bowel necrosis, peritonitis, and sepsis
  • Common in patients with atrial fibrillation, valvular diseases, or atherosclerosis
• Presentation
  • Sudden severe abdominal pain, nausea, vomiting: Visceral ischemia
  • Peritoneal signs, paralytic ileus, shock: Bowel necrosis and peritonitis
• Examination
  • [Contrast CT] Filling defect in SMA, poor bowel wall enhancement: Arterial occlusion and bowel ischemia
• Management
  • Emergency laparotomy: Remove thrombus and resect necrotic bowel
  • Thrombolytic, vasodilator drugs: Catheter infusion before surgery

Acute Appendicitis / 急性虫垂炎

• Overview
  • Acute inflammation of appendix due to obstruction by fecalith, food debris, or lymphoid hyperplasia
  • Common in 10-20s children and adults
• Presentation
  • Initial epigastric/periumbilical pain, anorexia, nausea, vomiting: Visceral pain from appendiceal distention
  • Later right lower quadrant pain, low-grade fever: Somatic pain due to peritoneal inflammation
• Examination
  • [Physical] McBurney’s point tenderness, rebound tenderness (Blumberg sign), muscle guarding: Peritoneal irritation
  • [Blood] WBC↑, CRP↑: Acute inflammation
  • [Ultrasound, CT] Enlarged appendix, fecalith, surrounding exudate: Confirms appendiceal inflammation
• Management
  • Appendectomy: Remove inflamed appendix
  • Antibiotics, fasting: Conservative treatment

Colonic Diverticulitis / 大腸憩室炎

• Overview
  • Inflammation of colonic diverticula due to fecal impaction and bacterial overgrowth
  • Common in middle-aged to elderly adults with chronic constipation
• Presentation
  • Lower abdominal pain and tenderness, low-grade fever: Local inflammation around diverticulum
• Examination
  • [Blood] WBC↑, CRP↑: Acute inflammation
  • [CT] Thickened bowel wall, surrounding inflammation: Inflammation around diverticulum
  • [Colonoscopy, Barium enema] Diverticula at tender points: Visualization of diverticulum
• Management
  • Fasting, IV fluids, antibiotics: Conservative treatment
  • Abscess drainage, colectomy: For abscess or perforation

Colonic Diverticular Hemorrhage / 大腸憩室出血

• Overview
  • Bleeding of colonic diverticula
  • Common in elderly
• Presentation
  • Painless bleeding, bloody stool: Direct bleeding from diverticular vessels
• Examination
  • [Endoscopy] Active bleeding from diverticula: Confirms diagnosis
  • [Contrast CT] Identifies bleeding site: Localization of bleeding
• Management
  • Rest, fasting, IV fluids: Conservative treatment
  • Endoscopic hemostasis (clipping, ligation): For active bleeding with identified source
  • Transcatheter arterial embolization (TAE): For massive bleeding

Gastrointestinal Neuroendocrine Neoplasm / 消化管神経内分泌腫瘍

• Overview
  • Slow-growing but malignant submucosal tumors, classified as well-differentiated NET or poorly-differentiated NEC
• Presentation
  • Asymptomatic, GI bleeding, abdominal pain: Due to local tumor growth
  • Flushing, wheezing, diarrhea: Carcinoid syndrome due to hormone secretion
• Examination
  • [Endoscopy] Smooth elevated lesion, bridging fold, delle: Submucosal tumor
  • [Urine, Blood] 5-HIAA↑, Serotonin↑: Hormone production by tumor
  • [Biopsy] Small uniform cells in cord/ribbon/rosette pattern, chromogranin A(+), silver stain(+): Confirms diagnosis
• Management
  • Surgical resection, EMR: For resectable cases
  • Octreotide, lanreotide, everolimus, streptozocin: For unresectable cases and carcinoid syndrome

Colonic Polyps / 大腸ポリープ

• Overview
  • Protruding lesions from colonic mucosa into lumen, most commonly adenomas (neoplastic) or hyperplastic polyps (non-neoplastic)
• Presentation
  • Asymptomatic, positive fecal occult blood test: Found during screening
  • Bloody stool: With larger polyps
• Examination
  • [Endoscopy] Protruding lesions, pit pattern analysis: Determines polyp type and risk
  • [Pathology] Adenoma, hyperplastic, serrated lesions: Confirm polyp type
• Management
  • Observation: Small hyperplastic polyps
  • Polypectomy, EMR: For large symptomatic polyps or suspected cancer

Colorectal Cancer / 大腸癌

• Overview
  • Malignant tumor arising from colon/rectal mucosa, mostly adenocarcinoma
  • Common in 50-70s adults
• Presentation
  • Asymptomatic, positive fecal occult blood test: Found during screening
  • Constipation, diarrhea, bloody stool, thin stools, abdominal pain: Due to tumor growth and obstruction
• Examination
  • [Endoscopy] Elevated or depressed lesions, pit pattern analysis: Early colorectal cancer (≤submucosal invasion)
  • [Endoscopy] Ulcerative lesions with raised edges: Advanced colorectal cancer (≥muscularis propria invasion)
  • [Barium enema] Irregular filling defects, apple core sign: Tumor causing luminal narrowing
  • [Blood] Anemia, CEA↑, CA19-9↑: Tumor markers (especially with liver metastasis)
  • [CT] Multiple low-density areas in liver: Common site of metastasis
• Management
  • [Early] Polypectomy, EMR, ESD: For early tumor
  • [Advanced] Surgical resection + lymph node dissection: For advanced tumor
  • [Metastasis] Chemotherapy (FOLFOX/FOLFIRI), surgical resection: For metastatic tumor

Familial Adenomatous Polyposis / 家族性大腸腺腫症

• Overview
  • Multiple adenomatous polyps throughout colon with risk of developing cancer, autosomal dominant disorder caused by APC gene mutation
  • Common in 15-40s adults with familial history
• Presentation
  • Bloody stools, diarrhea, abdominal pain: Due to numerous polyps
• Examination
  • [Endoscopy, Barium enema] Numerous polyps throughout colon
  • [Biopsy] Adenomatous polyps: Confirm polyps type
  • [Genetic testing] APC gene mutation: Confirms diagnosis
• Management
  • Total colectomy: Prevent development of colon cancer
  • Endoscopic polypectomy, aspirin: For cases with fewer polyps

Peutz-Jeghers Syndrome / Peutz-Jeghers症候群

• Overview
  • Multiple hamartomatous polyps throughout GI tract, autosomal dominant disorder caused by STK11/LKB1 gene mutation
• Presentation
  • Mucocutaneous pigmentation around lips: Resembling freckles/moles
  • Abdominal pain, bloody stools: GI symptoms due to polyps
• Examination
  • [Endoscopy] Hamartomatous polyps: Confirm polyps type
  • [Genetic testing] STK11/LKB1 mutation: Confirms diagnosis
• Management
  • Endoscopic polypectomy: For symptomatic or large polyps

Peritoneum Disorder / 腹膜疾患

Acute Peritonitis / 急性腹膜炎

• Overview
  • Acute inflammation of peritoneum, may progress to septic shock or SIRS
  • Commonly secondary to GI perforation or appendicitis
• Presentation
  • Severe abdominal pain, nausea, vomiting: Peritoneal inflammation
  • Fever, shallow breathing, tachycardia: Systemic response
• Examination
  • [Physical] Tenderness, muscle guarding, rebound tenderness, rigidity, reduced bowel sounds: Peritoneal irritation
  • [Blood] WBC↑, CRP↑: Inflammatory response
  • [X-ray, CT, Ultrasound] Free fluid, free air, abscess: Identify cause and complications
  • [Paracentesis] Fluid analysis: Determine nature of inflammation
• Management
  • IV fluids, antibiotics: Stabilization and infection control
  • Emergency surgery: Treat underlying cause

Pseudomyxoma Peritonei / 腹膜偽粘液腫

• Overview
  • Low-grade mucin-producing tumors spreading in peritoneal cavity, usually originates from appendix or ovary
• Presentation
  • Asymptomatic, abdominal distension, abdominal pain: Accumulation of mucinous material
• Examination
  • [CT] Jelly-like masses, septated fluid collections: Mucinous deposits in peritoneal cavity
  • [Pathology] Low-grade epithelial cells in mucin pools: Characteristic finding
• Management
  • Cytoreductive surgery: Remove tumor and mucinous deposits

Inguinal Hernia / 鼠径部ヘルニア

• Overview
  • Protrusion of abdominal contents through defects in inguinal area, divided into indirect inguinal (most common), direct inguinal, and femoral hernias
• Presentation
  • [Indirect inguinal] Bulge above inguinal ligament, lateral to inferior epigastric vessels: Common in male infants and adults
  • [Direct inguinal] Bulge above inguinal ligament, medial to inferior epigastric vessels: Common in middle-aged obese men
  • [Femoral] Bulge below inguinal ligament: Common in middle-aged women
• Examination
  • [Physical] Location of bulge: Distinguishes between types
  • [Physical] Tenderness, redness: Signs of incarceration
• Management
  • [Children] High ligation of hernia sac: Remove hernia sac
  • [Adults] Mesh repair: Strengthen weakened area
  • [Incarcerated hernia] Manual reduction, emergency surgery: Prevent complications

Anus Disorder / 肛門疾患

Hemorrhoids / 痔核

• Overview
  • Enlargement of anal cushions due to weakening of supporting tissue and venous congestion, classified as grade I to IV
• Presentation
  • Prolapse, bleeding during defecation: Enlargement and congestion of hemorrhoidal tissue
  • Severe pain in acute state: Incarcerated internal hemorrhoids, thrombosed external hemorrhoids
• Examination
  • [Physical] Digital rectal exam, anoscopy: Assess location and severity
• Management
  • Suppositories, ointments: Conservative treatment
  • ALTA injection: Sclerotherapy for internal hemorrhoids
  • Surgical ligation and excision: For Grade III-IV hemorrhoids

Perianal Abscess and Anal Fistula / 肛門周囲膿瘍・痔瘻

• Overview
  • Bacterial infection of anal glands leads to perianal abscess, can develop into chronic fistula
  • Common in males aged 30-40s, associated with Crohn’s disease
• Presentation
  • [Perianal Abscess] Severe anal pain, fever, perianal mass and redness: Acute bacterial infection
  • [Anal Fistula] Persistent pus drainage, intermittent swelling and tenderness: Chronic infection with fistula formation
• Examination
  • [Physical] Primary and secondary opening: Identifies fistula
• Management
  • [Perianal Abscess] Drainage, antibiotics: Treat acute infection
  • [Anal Fistula] Surgery: Open fistula

Anal Fissure / 裂肛

• Overview
  • Linear tear in anal canal epithelium caused by passage of hard stools
  • Common in young women, associated with constipation
• Presentation
  • Pain during and after defecation, bleeding: Tear in anal canal
  • Anal stenosis: Chronic inflammation and scarring
• Examination
  • [Physical] Tear, sentinel pile, polyp: Chronic inflammation leads to tissue changes
• Management
  • Conservative treatment: Primary treatment
  • Surgery: For severe cases

Liver Disorder / 肝疾患

Acute Viral Hepatitis / 急性ウイルス性肝炎

• Overview
  • Acute liver inflammation caused by hepatitis viruses (A-E), generally self-limiting but risk of fulminant hepatitis or chronicity
  • Transmitted through fecal-oral route (HAV, HEV) or blood/body fluids (HBV, HCV, HDV)
• Presentation
  • Fatigue, anorexia, nausea, vomiting, fever, muscle pain: Systemic inflammatory response
  • Jaundice, dark urine, hepatomegaly, abdominal pain: Liver inflammation and dysfunction
• Examination
  • [Blood] AST↑, ALT↑, bilirubin↑, PT prolonged: Hepatocyte damage and liver dysfunction
  • [Blood] IgM-HA-Ab, HBs-Ag, IgM-HBc-Ab, HCV-RNA, HCV-Ab: Acute viral infection
• Management
  • Bed rest: Increase hepatic blood flow
  • Diet therapy: Carbohydrate-rich diet, protein restriction
  • [HBV] Lamivudine: For HBV severe cases
  • [HCV] Direct-acting antivirals: For HCV chronic cases

Chronic Viral Hepatitis / 慢性肝炎

• Overview
  • Chronic liver inflammation >6 months, can progress to liver cirrhosis and hepatocellular carcinoma
  • Mainly caused by chronic infection of HBV or HCV
• Presentation
  • Asymptomatic, general fatigue, poor appetite: Chronic liver inflammation
• Examination
  • [Blood] AST↑, ALT↑: Liver cell damage
  • [Blood] HBs-Ag , IgG-HBc-Ab, HCV-RNA, HCV-Ab: Chronic viral infection
  • [Liver biopsy] Bridging fibrosis, piecemeal necrosis: Chronic inflammation and fibrosis
• Management
  • [HBV] Pegylated interferon, entecavir, tenofovir: Suppress HBV replication
  • [HCV] Direct acting antivirals: Suppress HCV replication
  • UDCA, glycyrrhizin: Liver protection

Fulminant Hepatitis / 劇症肝炎

• Overview
  • Acute liver failure with hepatic encephalopathy within 8 weeks of symptom onset
  • Commonly after acute hepatitis (viral, metabolic, autoimmune)
• Presentation
  • High fever, tachycardia, anorexia, nausea, vomiting: Systemic inflammatory response
  • Jaundice, ascites, edema: Liver dysfunction
  • Hepatic encephalopathy: Ammonia toxicity and cerebral edema
• Examination
  • [Blood] AST↑, ALT↑, bilirubin↑, LDH↑: Severe hepatocellular damage
  • [Blood] PT<40%, INR>1.5, albumin↓, ChE↓: Impaired liver synthesis
  • [Blood] Fischer ratio↓, NH3↑: Impaired liver metabolism
  • [Imaging] Liver atrophy, ascites: Advanced liver damage
• Management
  • Glucose-based fluids, respiratory control, antibiotics: Support vital functions
  • Hemodiafiltration + plasma exchange: Remove toxins artificially
  • Lactulose (hepatic encephalopathy), mannitol (cerebral edema), FFP (coagulation dysfunction): Treat complications
  • Antiviral therapy (HBV), steroids (autoimmune): Treat underlying cause
  • Liver transplantation: Definitive treatment

Liver Cirrhosis / 肝硬変

• Overview
  • End-stage liver disease with fibrosis and regenerative nodules, leading to liver failure and hepatocellular carcinoma
  • Common in chronic viral hepatitis or alcoholism
• Presentation
  • Asymptomatic, fatigue, anorexia, ascites, edema, jaundice: Liver dysfunction
  • Spider angiomas, palmar erythema, gynecomastia: Estrogen excess due to impaired metabolism
  • Esophageal varices, GI bleeding: Portal hypertension
  • Altered consciousness, flapping tremor: Hepatic encephalopathy
  • Fever, abdominal pain, peritoneal irritation: Spontaneous bacterial peritonitis
• Examination
  • [Blood] Pancytopenia (especially platelets): Hypersplenism
  • [Blood] AST↑, bilirubin↑, γ-GT↑, ALP↑: Liver damage and cholestasis
  • [Blood] PT prolonged, albumin↓, ChE↓: Decreased synthetic function
  • [Blood] Type IV collagen↑, hyaluronic acid↑: Fibrosis markers
  • [Imaging] Irregular liver surface, blunt edge, splenomegaly, ascites: Chronic liver disease
• Management
  • Direct-acting antivirals, nucleoside analogues: Treat underlying cause
  • High-energy low-salt diet, glycyrrhizin, UDCA: Liver protection
  • [Ascites] Salt restriction, diuretics, albumin: Manage fluid
  • [Varices] Endoscopic treatment: Prevent bleeding
  • [Encephalopathy] Low-protein diet, lactulose, branched-chain amino acids: Maintain consciousness
  • [Peritonitis] Antibiotics: Control infection
  • Liver transplantation: Ultimate treatment

Liver Abscess / 肝膿瘍

• Overview
  • Infectious collection in liver caused by bacteria (gram-negative rods) or amebae
  • Infection routes include biliary tract, portal vein, hepatic artery, direct spread
• Presentation
  • Fever, general fatigue: Systemic inflammatory response
  • RUQ pain, hepatomegaly, liver tenderness: Enlarged inflamed liver
• Examination
  • [Blood] WBC↑, ESR↑, CRP↑: Infection
  • [Blood] ALP↑, γ-GT↑: Cholestasis
  • [Ultrasound] Heterogeneous hypoechoic lesion: Abscess formation
  • [CT] Ring-enhancing hypodense lesion: Confirms abscess
  • [Aspiration] Yellow malodorous pus (bacterial) or chocolate-colored viscous pus (amebic): Identifies causative pathogen
• Management
  • [Bacterial] Antibiotics, percutaneous drainage: Treat infection and remove pus
  • [Amebic] Metronidazole: Eliminate amebae
  • Surgical drainage: For failed percutaneous drainage or rupture

Fatty Liver / 脂肪肝

• Overview
  • Abnormal accumulation of triglycerides in liver
  • Major causes include alcohol, obesity, diabetes mellitus
• Presentation
  • Asymptomatic, RUQ heaviness/pain: Enlarged liver
• Examination
  • [Ultrasound] Bright liver, increased hepatorenal contrast, deep echo attenuation, blurred vessels: Fat accumulation
  • [CT] Low density liver: Fat accumulation
  • [Liver biopsy] Fat deposits: Confirms diagnosis
• Management
  • Alcohol cessation: Treat alcoholism
  • Calorie restriction, diet modification, exercise: Treat obesity

Alcoholic Hepatitis / アルコール性肝炎

• Overview
  • Acute alcoholic liver injury triggered by sudden increase in alcohol consumption
  • Common in chronic heavy drinkers
• Presentation
  • Abdominal pain, fever, vomiting, diarrhea: Acute liver inflammation
  • Jaundice, altered consciousness, hepatomegaly: Liver dysfunction
• Examination
  • [Blood] AST↑ (AST>ALT), WBC↑, γ-GT↑, ALP↑: Liver damage and cholestasis
  • [Liver biopsy] Hepatocyte ballooning, Mallory-Denk bodies, neutrophil infiltration: Confirms diagnosis
• Management
  • Alcohol cessation: Treat alcoholism
  • Vitamin B1, hydration, balanced diet: Nutritional support
  • Glycyrrhizin, UDCA: Liver protection
  • Corticosteroids, plasma exchange, hemodiafiltration: Treatment for severe inflammation

Non-alcoholic Steatohepatitis / 非アルコール性脂肪肝炎

• Overview
  • Advanced non-alcoholic fatty liver disease with hepatocyte inflammation
  • Common in obesity, diabetes mellitus, hypertension
• Presentation
  • Fatigue, insomnia, hepatomegaly: Liver dysfunction
• Examination
  • [Blood] AST↑, γ-GT↑, platelets↓, hyaluronic acid↑, ferritin↑, TG↑, T.Cho↑: Liver dysfunction with metabolic abnormalities
  • [Ultrasound] Bright liver, increased hepatorenal contrast, deep echo attenuation: Fat accumulation
  • [CT] Low liver density: Fat accumulation
  • [Liver biopsy] Steatosis, hepatocyte ballooning, inflammation: Confirms diagnosis
• Management
  • Diet, exercise therapy: Treat obesity
  • Pioglitazone (diabetes), statins (hyperlipidemia), ARBs (hypertension): Treat underlying disease
  • Vitamin E: Liver protection

Drug-Induced Liver Injury / 薬物性肝障害

• Overview
  • Hepatocellular injury or cholestasis due to drug toxicity
  • Common causes include antibiotics, antipyretic analgesics, herbal medicines, supplements
• Presentation
  • Asymptomatic, fatigue, fever, rash, jaundice, pruritus: Liver injury with various severity
• Examination
  • [Blood]ALT↑, AST↑: Liver cell damage
  • [Blood] ALP↑, γ-GT↑, T.Bil↑: Bile stasis
  • [Blood] Eosinophils↑: Allergic reaction
• Management
  • Drug discontinuation: Improvement in most cases
  • Glycyrrhizin, UDCA, corticosteroids: Liver protection
  • N-acetylcysteine: For acetaminophen toxicity

Autoimmune Hepatitis / 自己免疫性肝炎

• Overview
  • Chronic progressive liver disease of autoimmune origin
  • Common in middle-aged women, often associated with other autoimmune diseases
• Presentation
  • Asymptomatic, fatigue, jaundice, poor appetite: Chronic liver inflammation
  • Fever, joint pain, rash: Systemic autoimmune manifestations
• Examination
  • [Blood] ALT↑ (ALT>AST), bilirubin↑: Liver cell damage
  • [Blood] γ-globulin↑, IgG↑, ESR↑, CRP↑: Inflammatory response
  • [Blood] ANA(+), anti-smooth muscle antibody(+): Autoimmune nature
  • [Liver biopsy] Interface hepatitis, liver cell necrosis: Confirms diagnosis
• Management
  • Corticosteroids, azathioprine: Anti-inflammatory and immunosuppressive
  • UDCA: Liver protection
  • Liver transplantation: For advanced cases

Primary Biliary Cholangitis / 原発性胆汁性胆管炎

• Overview
  • Chronic intrahepatic cholestasis characterized by chronic nonsuppurative destructive cholangitis
  • Common in middle-aged women, often associated with other autoimmune diseases
• Presentation
  • Asymptomatic, pruritus, jaundice: Bile stasis
• Examination
  • [Blood] ALP↑, γ-GT↑, T.Cho↑, bilirubin↑: Cholestasis
  • [Blood] Eosinophils↑, ESR↑, IgM↑: Inflammatory response
  • [Blood] Anti-mitochondrial antibody(+): Autoimmune nature
  • [Liver biopsy] Chronic nonsuppurative destructive cholangitis: Confirms diagnosis
• Management
  • UDCA, bezafibrate: Improve bile flow
  • Cholestyramine, antihistamines: For pruritus
  • Liver transplantation: For advanced cases

Idiopathic Portal Hypertension / 特発性門脈圧亢進症

• Overview
  • Portal hypertension without cirrhosis or portal/hepatic vein obstruction
  • Common in middle-aged women, often associated with autoimmune diseases
• Presentation
  • Esophageal varices, splenomegaly, pancytopenia: Due to portal hypertension
• Examination
  • [Blood] γ-globulin↑, autoantibodies: Suggests autoimmune background
• Management
  • Endoscopic treatment: For esophageal varices
  • Partial splenic embolization, splenectomy: For hypersplenism

Budd-Chiari Syndrome / Budd-Chiari症候群

• Overview
  • Obstruction/stenosis of hepatic veins or inferior vena cava, causing post-hepatic portal hypertension
  • Primary (coagulation disorders, myeloproliferative disorders) or secondary (liver cancer, thrombosis, heart failure)
• Presentation
  • [Acute] Abdominal pain, ascites, fever: Rapid development of hepatic congestion
  • [Chronic] Asymptomatic, progressive portal hypertension: Gradual hepatic congestion
• Examination
  • [Blood] AST↑, ALT↑: Liver cell damage
  • [Imaging] Obstruction/stenosis of hepatic veins or IVC: Direct visualization of blockage
• Management
  • Balloon angioplasty, surgical shunting: Widen or bypass obstructed vessels

Hepatic Cyst / 肝囊胞

• Overview
  • Fluid-filled sacs in liver, mostly benign but can be polycystic liver disease or echinococcus
• Presentation
  • Asymptomatic: In most cases
  • Abdominal discomfort , obstructive jaundice: In large cysts
• Examination
  • [Ultrasound] Anechoic lesion, posterior acoustic enhancement: Fluid-filled cyst
  • [CT, MRI] Well-defined fluid-density lesion: Confirms cyst
• Management
  • Observation: For asymptomatic cases
  • Aspiration, surgical resection: For symptomatic cases

Hepatic Hemangioma / 肝血管腫

• Overview
  • Most common benign primary liver tumor
  • Common in middle-aged women
• Presentation
  • Asymptomatic: In most cases
  • Abdominal discomfort, bleeding tendency: In large tumors or consumption coagulopathy
• Examination
  • [Ultrasound] Hyperechoic lesion: Endothelium-rich tumor
  • [CT, MRI] Peripheral nodular enhancement, centripetal filling: Characteristic vascular pattern
• Management
  • Observation: For asymptomatic cases
  • Surgical resection: For symptomatic cases

Hepatocellular Carcinoma / 肝細胞癌

• Overview
  • Malignant tumor from hepatocytes, characterized by multistep and multicentric carcinogenesis
  • Common in patients with chronic liver diseases (viral hepatitis B/C, NASH)
• Presentation
  • Asymptomatic: Often found during screening
• Examination
  • [Blood] AFP↑, PIVKA-II↑, AFP-L3↑: Tumor markers
  • [Ultrasound] Well-defined nodule with halo, mosaic pattern: Tumor with capsule and septum
  • [Contrast CT/MRI] Hyperenhancement in arterial phase, washout in portal/delayed phase: Hypervascular tumor
• Management
  • [Child-Pugh A/B, local] Resection, ablation, chemoembolization: For local compensated tumor
  • [Child-Pugh A/B, metastatic] Targeted therapy: For metastatic compensated tumor
  • [Child-Pugh C] Liver transplantation, palliative care: For uncompensated tumor

Intrahepatic Cholangiocarcinoma / 肝内胆管癌

• Overview
  • Malignant tumor from intrahepatic bile duct epithelium
• Presentation
  • Asymptomatic, obstructive jaundice: Depend on hilar or peripheral types
• Examination
  • [Blood] ALP↑, γ-GT↑, bilirubin↑: Bile duct obstruction
  • [Blood] CA19-9↑, CEA↑: Tumor markers
  • [CT/MRI] Delayed enhancement, bile duct dilatation: Differentiate from HCC
• Management
  • Surgical resection: For local tumor
  • Gemcitabine + Cisplatin: For metastatic tumor

Metastatic Liver Cancer / 転移性肝癌

• Overview
  • Metastatic tumor from other organ, more common than primary liver cancer
  • Common primary sites: colorectal, pancreatic, gastric, biliary tract, lung, breast, ovarian cancer
• Presentation
  • Asymptomatic: Often found during screening
  • Abdominal distension, jaundice, ascites, anorexia: Liver dysfunction in advanced disease
• Examination
  • [Blood] CEA↑ (colorectal), CA19-9↑ (pancreatic/biliary): Primary tumor markers
  • [Blood] ALP↑, γ-GT↑, LDH↑: Cholestasis
  • [Ultrasound] Bull’s eye sign: Tumor with capsule and central necrosis
  • [CT] Ring enhancement of hypodense lesions: Tumor with capsule and central necrosis
• Management
  • Surgical resection: For colorectal cancer and GIST
  • Chemotherapy: For most cancer

Biliary Tract Disorder / 胆道疾患

Cholelithiasis / 胆石症

• Overview
  • Stones in biliary system (gallbladder, common bile duct, intrahepatic)
  • Common in middle-aged and older adults
• Presentation
  • Asymptomatic, RUQ/epigastric pain after meals, radiate to right shoulder/back, nausea, vomiting: Gallstone temporarily obstructs bile duct
• Examination
  • [Blood] γ-GT↑, ALP↑, bilirubin↑: Biliary obstruction
  • [Ultrasound] High-echoic image, acoustic shadow: Stone reflects sound waves
  • [CT] High-density stone: Visualize stones
  • [MRCP, ERCP] Filling defects: Visualize stones
• Management
  • [Gallbladder stone] Observation, (asymptomatic), laparoscopic/open cholecystectomy (symptomatic), NSAID/anticholinergics: Remove gallbladder with stones and control pain
  • [CBD stone] Endoscopic sphincterotomy (EST), endoscopic papillary balloon dilatation (EPBD): Remove CBD stones
  • [Intrahepatic stone] Percutaneous transhepatic cholangioscopy (PTCS), hepatectomy (atrophy, cancer): Remove intrahepatic stones or liver

Acute Cholecystitis / 急性胆囊炎

• Overview
  • Acute inflammation of gallbladder caused by gallstones impaction and bacterial infection
  • Common in middle-aged and older adults with gallstone history
• Presentation
  • RUQ pain, fever, nausea, vomiting: Gallbladder infection
  • Tenderness, muscle guarding, Murphy’s sign: Local peritoneal irritation
• Examination
  • [Blood] WBC↑, CRP↑: Active infection
  • [Blood] ALP↑, γ-GT↑, bilirubin↑: Biliary obstruction
  • [Ultrasound, CT] Gallbladder wall thickening, enlargement, debris, impacted stones, sonographic Murphy’s sign: Gallbladder inflammation
• Management
  • Fasting, IV fluids, antibiotics, analgesics: Treat infection and pain
  • Percutaneous transhepatic gallbladder drainage/aspiration (PTGBD): Reduce gallbladder pressure if unstable
  • Laparoscopic cholecystectomy: Remove gallbladder if stable

Acute Cholangitis / 急性胆管炎

• Overview
  • Acute inflammation of bile ducts caused by obstruction and bacterial infection, leading to sepsis in severe cases
  • Common in middle-aged and older adults with gallstone history
• Presentation
  • Abdominal pain, fever with chills, jaundice (Charcot’s triad): Bile duct infection and obstruction
  • Shock, altered consciousness (Reynolds’ pentad): Endotoxin and bacteria enter bloodstream in severe cases
• Examination
  • [Blood] WBC↑, CRP↑: Active infection
  • [Blood] ALP↑, γ-GT↑, bilirubin↑: Biliary obstruction
  • [Blood] AST↑, ALT↑: Liver damage
  • [Ultrasound, CT] Dilated bile ducts, CBD stones: CBD obstruction
• Management
  • Fasting, IV fluids, antibiotics, analgesics: Treat infection and pain
  • Endoscopic biliary drainage (EBD), percutaneous transhepatic biliary drainage (PTBD): Reduce biliary tract pressure if unstable
  • Endoscopic sphincterotomy (EST), endoscopic papillary balloon dilatation (EPBD): Remove stones if stable

Primary Sclerosing Cholangitis / 原発性硬化性胆管炎

• Overview
  • Progressive chronic inflammation of intra/extrahepatic bile ducts causing fibrous stenosis
  • Common in 20s and 60s adults, often associated with ulcerative colitis
• Presentation
  • Asymptomatic, fluctuating jaundice, pruritus: Cholestasis
• Examination
  • [Blood] γ-GT↑, ALP↑, bilirubin↑: Biliary obstruction
  • [Blood] AST↑, ALT↑: Liver damage
  • [Blood] P-ANCA(+): Autoimmune nature
  • [ERCP, MRCP] Intra/extrahepatic bile duct strictures (beaded appearance): Bile duct stenosis
• Management
  • UDCA, bezafibrate, cholestyramine, antihistamines: Improve bile flow and relieve pruritus
  • Biliary drainage: Control cholangitis and reduce jaundice
  • Liver transplantation: Only curative treatment for advanced cases

Congenital Biliary Dilatation / 先天性胆道拡張症

• Overview
  • Congenital malformation with localized dilatation of extrahepatic bile ducts and pancreaticobiliary maljunction, high risk of biliary tract cancer
  • Common in children and young adults
• Presentation
  • Asymptomatic, abdominal pain, jaundice, abdominal mass: Biliary dilatation and bile stasis
• Examination
  • [Blood] γ-GT↑, ALP↑, amylase↑: Bile stasis and pancreatic enzyme reflux
  • [CT, Ultrasound] Dilatation of CBD: Biliary dilatation
  • [MRCP, ERCP] Cystic/fusiform dilatation of CBD: Biliary dilatation
  • [MRCP, ERCP] Abnormal junction of pancreatic duct and CBD outside duodenal wall: Pancreaticobiliary maljunction
• Management
  • Extrahepatic bile duct resection, cholecystectomy, biliary reconstruction: Prevent biliary tract cancer

Biliary Atresia / 胆道閉鎖症

• Overview
  • Congenital obstruction of extrahepatic bile ducts
  • Common in female infants
• Presentation
  • Prolonged jaundice, clay-colored stool: Bile duct obstruction
  • Bleeding tendency, bone abnormalities: Fat-soluble vitamin malabsorption
• Examination
  • [Blood] γ-GT↑, ALP↑, bilirubin↑: Bile duct obstruction
  • [CT, Ultrasound] Absent gallbladder or bile ducts: Biliary atresia
• Management
  • Kasai portoenterostomy: Bypass biliary atresia
  • Liver transplantation: If Kasai procedure fails

Gallbladder Polyp / 胆囊ポリープ

• Overview
  • Localized protruding lesions on gallbladder mucosa
• Presentation
  • Asymptomatic: Most cases
• Examination
  • [Ultrasound] Protruding lesion in gallbladder: Often found during screening
• Management
  • Observation: For typical polyps
  • Cholecystectomy: For polyp with cancer risk (>10mmm, broad-based)

Gallbladder Adenomyomatosis / 胆囊腺筋腫症

• Overview
  • Excessive proliferation of Rokitansky-Aschoff sinuses, hyperplasia of gallbladder epithelium and smooth muscle
• Presentation
  • Asymptomatic: Most cases
• Examination
  • [Ultrasound] Thickened gallbladder wall, comet-like echo: Proliferated Rokitansky-Aschoff sinuses
  • [MRCP] Pearl necklace appearance: Proliferated Rokitansky-Aschoff sinuses
• Management
  • Observation: For asymptomatic cases
  • Laparoscopic cholecystectomy: For symptomatic cases or lesion with cancer risk

Gallbladder Cancer / 胆囊癌

• Overview
  • Malignant tumor arising in gallbladder, poor prognosis due to late detection
  • Common in elderly females, risk factors include pancreaticobiliary maljunction and gallbladder dysplasia
• Presentation
  • Asymptomatic, RUQ pain, nausea, vomiting, weight loss: Local tumor effects
  • Jaundice, pruritus: Bile duct obstruction in advanced tumor
• Examination
  • [Blood] ALP↑, γ-GT↑: Bile duct obstruction
  • [Blood] CA19-9↑, CEA↑: Tumor markers
  • [Ultrasound] Irregular mass, wall thickening: Suspicious lesions
  • [EUS, CT, MRCP, ERCP] Mass lesion, filling defect: Assess extent of disease
• Management
  • [Resectable] Cholecystectomy + gallbladder bed resection + lymph node dissection: For local tumor
  • [Unresectable] Gemcitabine + cisplatin/S-1: For metastatic tumor
  • [Symptomatic] Biliary drainage (ENBD, stent): Relieve obstructive jaundice

Cholangiocarcinoma / 胆管癌

• Overview
  • Malignant tumor arising in extrehepatic bile duct, poor prognosis due to late detection
  • Common in elderly males, risk factors include pancreaticobiliary maljunction and primary sclerosing cholangitis
• Presentation
  • Jaundice, pruritus, painless gallbladder enlargement (Courvoisier’s sign): Bile duct obstruction
  • Upper abdominal pain, weight loss, fever: Local tumor effects
• Examination
  • [Blood] ALP↑, γ-GT↑: Bile duct obstruction
  • [Blood] CA19-9↑, CEA↑: Tumor markers
  • [Ultrasound] Dilated bile ducts, mass lesion: Tumor obstruction
  • [EUS, CT, MRCP, ERCP] Mass lesion, filling defect: Assess extent of disease
• Management
  • [Resectable] Hepatectomy + bile duct resection + lymph node dissection: For local tumor in hilar region
  • [Resectable] Pancreaticoduodenectomy + lymph node dissection: For local tumor in distal region
  • [Unresectable] Gemcitabine + cisplatin/S-1: For metastatic tumor
  • [Symptomatic] Biliary drainage (ENBD, stent, PTBD): Relieve obstructive jaundice

Peripapillary Carcinoma / 乳頭部癌

• Overview
  • Malignant tumor arising in ampulla of Vater
  • Common in 60s males
• Presentation
  • Fluctuating jaundice, dark urine, painless gallbladder enlargement (Courvoisier’s sign): Bile duct obstruction
  • Fever, abdominal pain: Local tumor effects
• Examination
  • [Blood] ALP↑, γ-GT↑: Bile duct obstruction
  • [Blood] CA19-9↑, CEA↑: Tumor markers
  • [Ultrasound] Dilated pancreatic and bile ducts, mass lesion: Tumor obstruction
  • [Endoscopy] Irregular mass at duodenal papilla: Direct visualization
  • [EUS, CT, MRCP] Mass lesion, filling defect: Assess extent of disease
• Management
  • [Resectable] Pancreaticoduodenectomy + lymph node dissection: For local tumor
  • [Unresectable] Chemotherapy: For metastatic tumor
  • [Symptomatic] Biliary drainage (ENBD, stent, PTBD): Relieve obstructive jaundice

Pancreas Disorder / 膵疾患

Acute Pancreatitis / 急性膵炎

• Overview
  • Self-digestion of pancreas by activated pancreatic enzymes, leading to multi-organ failure in severe cases
  • Common causes include alcohol and gallstones
• Presentation
  • Epigastric/back pain, fever, nausea, vomiting: Pancreatic inflammation, improves in knee-chest position
  • Abdominal tenderness, muscle guarding, decreased bowel sounds: Peritoneal irritation
  • Shock, respiratory failure, oliguria, altered consciousness: Cytokine storm due to pancreas self-digestion in severe cases
• Examination
  • [Blood] Amylase↑, lipase↑: Pancreatic enzyme activation
  • [Blood] Platelets↓, Ca↓, CRP↑, BUN↑, Cr↑, coagulation disorders: Multi-organ dysfunction in severe cases
  • [CT/MRI/US] Pancreatic swelling, blurred outline, fluid collection: Pancreatic self-digestion
• Management
  • NPO, IV fluids, pain control: Conservative treatment in mild cases
  • Antibiotics, protease inhibitors, enteral nutrition: Prevent complications in severe cases
  • ERCP, EST: Resolve obstruction if gallstone present
  • Drainage, necrosectomy: Remove necrotic tissue

Chronic Pancreatitis / 慢性膵炎

• Overview
  • Progressive and irreversible pancreatic damage with fibrosis and calcification
  • Common in middle-aged men with long-term alcohol use
• Presentation
  • Recurrent epigastric/back pain: Pancreatic inflammation, worsens with alcohol/fat intake
  • Steatorrhea, diarrhea: Exocrine insufficiency in decompensated stage
  • Diabetes symptoms, weight loss: Endocrine insufficiency in decompensated stage
• Examination
  • [Blood] Amylase/lipase↑ or ↓: Compensated or decompensated pancreatic function
  • [US/CT] Pancreatic duct dilation, pancreatic stones: Pancreatic duct obstruction by stones
  • [MRCP/ERCP] Pancreatic duct dilation, filling defects: Pancreatic duct obstruction by stones
  • [BT-PABA test] PABA excretion↓: Exocrine insufficiency
• Management
  • Alcohol/smoking cessation, low-fat diet: Prevent progression
  • NSAIDs, anticholinergics, enzyme inhibitors: Relieve symptoms
  • ESWL, endoscopic treatment: Remove stones
  • Pancreatic enzymes, insulin: For exocrine and endocrine insufficiency

Autoimmune Pancreatitis / 自己免疫性膵炎

• Overview
  • Chronic progressive pancreatitis with autoimmune nature
  • Common in elderly males
• Presentation
  • Jaundice, epigastric discomfort: Pancreatic inflammation
  • Diabetes mellitus: Pancreatic endocrine dysfunction
• Examination
  • [Blood] γ-globulin↑, IgG↑, IgG4↑, ANA(+), RF(+): Autoimmune nature
  • [Blood] Amylase↑, lipase↑, γ-GT↑, ALP↑: Pancreatic inflammation and biliary obstruction
  • [CT/MRI/US] Pancreatic enlargement: Pancreatic inflammation
  • [ERCP/MRCP] Pancreatic duct narrowing: Pancreas chronic inflammation
  • [Biopsy] IgG4-positive plasma cell infiltration, fibrosis: Confirms diagnosis
• Management
  • Corticosteroids: Suppress inflammation

Pancreatic Cancer / 膵癌

• Overview
  • Malignant tumor arising from pancreatic ductal epithelium, poor prognosis due to late detection
  • Common in elderly, risk factors include chronic pancreatitis, diabetes, smoking
• Presentation
  • Abdominal/back pain: Local tumor invasion
  • Jaundice: Biliary tract obstruction
  • Weight loss, indigestion, diabetes: Impaired pancreatic function
• Examination
  • [Blood] Amylase↑, lipase↑: Pancreatic damage
  • [Blood] CA19-9↑, SPAN-1↑, DUPAN-2↑, CEA↑: Tumor markers
  • [CT, US] Hypovascular pancreatic mass, dilated pancreatic duct: Tumor obstruction
  • [MRCP, ERCP] Stenosis/obstruction of pancreatic/bile duct: Tumor obstruction
  • [EUS-FNA] Malignant ductal cells: Confirmatory diagnosis
• Management
  • [Resectable] Pancreaticoduodenectomy, distal pancreatectomy (with/without neoadjuvant/adjuvant therapy): For tumors without major vessel invasion
  • [Unresectable] Chemotherapy (FOLFIRINOX, gemcitabine+nab-paclitaxel): For tumor with major vessel invasion or metastasis
  • [Paliative] Biliary stenting, gastric bypass, pain control: Symptom management

Pancreatic Pseudocyst / 膵仮性囊胞

• Overview
  • Non-epithelial-lined pancreatic cyst formed by encapsulation of leaked pancreatic fluid and necrotic material
  • Commonly from pancreatitis or trauma
• Presentation
  • Asymptomatic, abdominal discomfort, nausea, vomiting: Compression by cysts
• Examination
  • [CT, US] Unilocular cyst: Confirms diagnosis
• Management
  • Observation: May resolve spontaneously
  • Drainage (endoscopic, percutaneous, surgical): For persistent symptoms or complications

Intraductal Papillary Mucinous Neoplasm / 膵管内乳頭粘液性腫瘍

• Overview
  • Papillary tumor growing within pancreatic ducts with mucin production, may progress to malignant tumor
  • Common in elderly males, mostly in pancreatic head
• Presentation
  • Asymptomatic, abdominal discomfort, acute pancreatitis: Tumor compression and duct obstruction
• Examination
  • [US/CT/MRI] Dilated pancreatic duct (main duct type), grape-like multicystic lesions (branch duct type): Different patterns of ductal involvement
• Management
  • Observation: For low malignant risk cases
  • Pancreaticoduodenectomy: For high malignant risk cases

Mucinous Cystic Neoplasm / 粘液性囊胞腫瘍

• Overview
  • Cystic tumor with mucin-producing epithelium and ovarian-like stroma, may be malignant
  • Common in middle-aged women, mostly in pancreatic body/tail
• Presentation
  • Asymptomatic, abdominal discomfort: Tumor compression
• Examination
  • [US/CT/MRI] Huge multilocular cyst: Orange-like appearance
• Management
  • Distal pancreatectomy: Due to malignant potential

Serous Cystic Neoplasm / 漿液性囊胞腫瘍

• Overview
  • Cystic tumor with serous fluid-filled cysts, mostly benign
  • Common in elderly women, mostly in pancreatic body/tail
• Presentation
  • Asymptomatic: Smaller tumor
• Examination
  • [US/CT/MRI] Clustered microcysts: Honeycomb appearance
• Management
  • Observation: Due to low malignant potential

Endocrinology / 内分泌科

Pituitary Gland Disorder / 下垂体疾患

Acromegaly & Pituitary Gigantism / 先端巨大症・下垂体性巨人症

• Overview
  • Excess growth hormone secretion from pituitary adenoma
• Presentation
  • Prominent brow, enlarged nose/lips, protruding jaw, enlarged hands/feet, macroglossia: High GH causes bone and soft tissue overgrowth
  • Headache, visual disturbance: Pituitary tumor compressing optic chiasm
• Examination
  • [Blood] GH↑ (not suppressed by glucose load), IGF-1↑: Excess GH secretion
  • [MRI/CT] Pituitary adenoma: Identify tumor
  • [X-ray] Sella turcica ballooning/double floor, enlarged sinuses, cauliflower-like terminal phalanges, enlarged sesamoid bones, thick heel pad: Bone and soft tissue overgrowth
• Management
  • Transsphenoidal surgery: Remove pituitary adenoma
  • Somatostatin analogs (octreotide, lanreotide, pasireotide), GH receptor antagonist (pegvisomant): Suppress GH secretion/action
  • Radiation therapy: For recurrent or inoperable cases

Hyperprolactinemia / 高プロラクチン血症

• Overview
  • Excessive prolactin secretion from pituitary adenoma or due to medication
• Presentation
  • Galactorrhea, menstrual irregularities, infertility (women): High prolactin suppresses LH/FSH
  • Decreased libido, penile atrophy (men): High prolactin suppresses testosterone
  • Headache, visual disturbance: Pituitary tumor compressing optic chiasm
• Examination
  • [Blood] Prolactin↑, FT4↓ (in some cases): Excess prolactin secretion
  • [MRI/CT] Pituitary/hypothalamic lesions: Identify tumor
• Management
  • Dopamine agonists (bromocriptine, cabergoline): Suppress prolactin secretion
  • Transsphenoidal surgery: Remove pituitary adenoma or hypothalamic lesions
  • Radiation therapy: For recurrent or inoperable cases
  • Discontinue causative medication, thyroid hormone replacement: Treat other possible causes

Cushing’s Disease / Cushing病

• Overview
  • Excessive ACTH secretion from pituitary adenoma
• Presentation
  • Moon face, central obesity, buffalo hump, purple striae, thin skin: High cortisol causes abnormal fat distribution and skin
  • Hypertension, edema, glucose intolerance, osteoporosis, easy bruising: High cortisol causes metabolic effects
  • Acne, menstrual irregularities, hirsutism: High androgens causes reproductive effects
• Examination
  • [Blood] ACTH↑, cortisol↑, DHEA-S↑: ACTH-dependent hypercortisolism
  • [Blood] Na↑, K↓, pH↑: Mineralocorticoid effects
  • [Endocrine tests] Cortisol circadian rhythm loss, absence low-dose dexamethasone suppression: Autonomous ACTH secretion
  • [MRI/CT] Pituitary adenoma: Identify tumor
  • [Inferior petrosal sinus sampling] ACTH↑: Confirm pituitary source
• Management
  • Transsphenoidal surgery: Remove pituitary adenoma
  • Pasireotide, cabergoline, metyrapone, trilostane, mitotane: Suppress ACTH/cortisol secretion
  • Radiation therapy: For recurrent or inoperable cases

Panhypopituitarism / 汎下垂体機能低下症

• Overview
  • Deficiency of multiple anterior pituitary hormones
  • Causes include supresellar/pituitary tumor, lymphocytic hypophysitis, Sheehan syndrome
• Presentation
  • Amenorrhea, breast/genital atrophy (women), decreased libido, testicular atrophy (men): LH/FSH deficiency
  • Decreased muscle mass, increased body fat: GH deficiency
  • Cold intolerance, dry skin, constipation, bradycardia: TSH deficiency
  • Fatigue, anorexia, hypotension, hypoglycemia: ACTH deficiency
• Examination
  • [Blood] Hormone levels↓ (LH/FSH, GH, TSH, ACTH): Pituitary dysfunction
  • [Blood] Target organ hormones↓ (sex hormones , IGF-I, FT4/FT3, cortisol): End-organ hormone deficiency
  • [CT/MRI] Pituitary/hypothalamic lesions: Identify causes
• Management
  • Sex hormones, levothyroxine, hydrocortisone: Hormone replacement
  • Surgery, medication, radiation: Treatment of underlying cause

Growth Hormone Deficiency / 成長ホルモン分泌不全性低身長症

• Overview
  • Insufficient GH secretion leading to decreased growth velocity
  • Causes include idiopathic (peripartum events) or tumor
• Presentation
  • Height < -2.0 SD, growth velocity < -1.5 SD, proportionate stature: Decreased growth velocity
  • Hypoglycemia in infants: Due to GH deficiency
  • Other pituitary hormone deficiency: In cases of combined deficiency
• Examination
  • [Stimulation tests] GH peak↓ with insulin/arginine/L-dopa/clonidine/glucagon/GHRP-2: Confirms GH deficiency
  • [CT/MRI] Pituitary hypoplasia or tumor: Identify organic causes
• Management
  • GH replacement: Hormone replacement therapy

Hypogonadotropic Hypogonadism / ゴナドトロピン単独欠損症

• Overview
  • Insufficient LH/FSH secretion leading to decreased gonadal function
  • Causes include congenital (Kallmann syndrome, Laurence-Moon-Biedl syndrome, Prader-Willi syndrome) or acquired (tumor, inflammation)
• Presentation
  • Genital atrophy, absent secondary sexual development: Incomplete sexual development
  • Amenorrhea, decreased libido, infertility: Decreased gonadal function
  • [Kallmann syndrome] Anosmia: Olfactory nerve hypoplasia
  • [Prader-Willi syndrome] Hypotonia, hypogonadism, hypomentia, obesity: Chromosomal loss or inactivation
• Examination
  • [Blood] LH/FSH↓, androgens/estrogens↓: Confirms gonadotropin deficiency
• Management
  • Testosterone/estrogen replacement: For secondary sexual development
  • Gonadotropin therapy, Holmstrom/Kaufmann therapy: For fertility treatment

Isolated ACTH Deficiency / ACTH単独欠損症

• Overview
  • Insufficient ACTH secretion leading to adrenal insufficiency
  • Causes include autoimmune or immune checkpoint inhibitors
• Presentation
  • Fatigue, weight loss, anorexia, hypotension, hypoglycemia, hyponatremia: Cortisol deficiency
• Examination
  • [Blood] ACTH↓, cortisol↓: Confirms ACTH deficiency
• Management
  • Hydrocortisone replacement: Hormone replacement therapy

SIADH / バソプレシン分泌過剰症

• Overview
  • Water retention and hyponatremia due to inappropriate continuous AVP secretion
  • Causes include malignancies (SCLC), medications (vincristine), CNS diseases, thoracic diseases
• Presentation
  • Fatigue, decreased appetite, altered consciousness: Brain edema due to dilutional hyponatremia
• Examination
  • [Blood] AVP↑: Inappropriate AVP secretion
  • [Blood] Osmolality↓, Na↓, BUN↓, uric acid↓: Water retention and increased GFR
  • [Urine] Osmolality↑, Na↑: Highly-concentrated urine
• Management
  • [Mild] Water restriction, salt supplementation: Correct hyponatremia
  • [Severe] Furosemide + 3% saline: Rapid correction of severe hyponatremia
  • [Ectopic] V2 receptor antagonist (mozavaptan), demeclocycline: Block AVP effect
  • Treat underlying disease: Address primary cause

Diabetes Insipidus / 尿崩症

• Overview
  • Excessive dilute urine due to insufficient secretion of AVP (central DI) or kidney resistance to AVP (nephrogenic DI)
• Presentation
  • Polyuria, thirst, polydipsia: Inability to concentrate urine
• Examination
  • [Urine] Osmolality↓, specific gravity↓: Impaired water reabsorption
  • [Diagnostic test] No response to hypertonic saline test / water deprivation test: Differentiate DI from psychogenic polydipsia
  • [DDAVP test] Response to vasopressin: Differentiate central DI from nephrogenic DI
• Management
  • [Central] Desmopressin acetate (DDAVP): Replaces AVP
  • [Nephrogenic DI] Thiazide diuretics: Reduces urine output

Thyroid Gland Disorder / 甲状腺疾患

Parathyroid Gland Disorder / 副甲状腺疾患

Adrenal Gland Disorder / 副腎疾患

Neuroendocrine Tumor / 神経内分泌腫瘍

Carbohydrate and Lipid Metabolism Disorder / 糖・脂質代謝異常

Uric Acid and Bone Metabolism Disorder / 尿酸・骨代謝異常

Congenital Metabolism Disorder / 先天代謝異常

Nutritional Disorder / 栄養異常

Nephrology / 腎臓科

Electrolytes Metabolism Disorder / 電解質代謝異常

Glomerular Disorder / 糸球体疾患

Tubulointerstitial Disorder / 尿細管・間質性疾患

Renal Injury with Systemic Disorder / 全身性疾患に伴う腎障害

Renal Vascular Disorder / 腎血管性疾患

Renal Failure / 腎不全

Hematology / 血液科

Hemostasis Disorder (Primary) / 止血の異常（一次）

Hemostasis Disorder (Secondary) / 止血の異常（二次）

Red Blood Cell Disorder (Nonehemolysis) / 赤血球の異常（非溶血）

Red Blood Cell Disorder (Hemolysis) / 赤血球の異常（溶血）

White Blood Cell Disorder / 白血球の異常

Myeloid Neoplasm / 骨髄系腫瘍

Lymphoid Neoplasm / リンパ系腫瘍

Rheumatology / リウマチ科

Immunodeficiency / 免疫不全

Allergy / アレルギー

Collagen Disease (Arthritis) / 膠原病（関節炎）

Collagen Disease (Systemic) / 膠原病（全身性）

Collagen Disease (Vasculitis) / 膠原病（血管炎）

Infectious Diseases / 感染症科

Gram-Positive Bacteria Infection / グラム陽性菌感染症

Gram-Negative Bacteria Infection / グラム陰性菌感染症

Miscellaneous Bacteria Infection / その他の細菌感染症

DNA Virus Infection / DNAウイルス感染症

RNA Virus Infection / RNAウイルス感染症

Fungus Infection / 真菌感染症

Parasite Infection / 寄生虫感染症

Neurology / 神経科

Cerebrovascular Disorder / 脳血管障害

Atherothrombotic Infarction / アテローム血栓性脳梗塞

• Overview
  • Cerebral infarction caused by atherosclerosis in intra/extracranial major arteries, leading to cerebral ischemia and necrosis
  • Common in middle-aged and elderly, risk factors include hypertension, diabetes, dyslipidemia, smoking, heavy drinking
• Presentation
  • Transient weakness, hemiplegia, numbness, amaurosis fugax: TIA as prodromal symptoms
  • Progressive hemiplegia, dysarthria: Gradual onset during rest due to progressive vessel occlusion
• Examination
  • [CT] Normal or early CT sign (hyperacute), low-density area (acute to chronic): Infarct evolution
  • [MRI] DWI high intensity (hyperacute), T1 low/T2 & FLAIR high intensity (acute to chronic): Infarct evolution
  • [CTA, MRA, Angiography] Arterial stenosis/occlusion: Atherosclerotic changes
• Management
  • [Acute] rt-PA (within 4.5h), mechanical thrombectomy (within 8h): Recanalization
  • [Acute] Edaravone, antiplatelet drugs, anticoagulants, glycerol: Neuroprotection and antithrombotic
  • [Chronic] Risk factor management, antiplatelet therapy: Prevention of recurrence

Cardioembolic Infarction / 心原性脳塞栓症

• Overview
  • Cerebral infarction caused by embolism from cardiac thrombus, leading to cerebral ischemia and necrosis
  • Common in patients with atrial fibrillation, recent myocardial infarction, valvular disease, infectious endocarditis
• Presentation
  • Sudden hemiplegia, dysarthria, aphasia, consciousness disturbance: Abrupt onset during daytime activity
• Examination
  • [CT] Normal or early CT sign (hyperacute), low-density area (acute to chronic): Infarct evolution
  • [MRI] DWI high intensity (hyperacute), T1 low/T2 & FLAIR high intensity (acute to chronic): Infarct evolution
  • [CTA, MRA, Angiography] Vessel occlusion without significant atherosclerosis: Embolic nature
  • [Echocardiography] Cardiac thrombus: Source of embolism
• Management
  • [Acute] rt-PA (within 4.5h), mechanical thrombectomy (within 8h): Recanalization
  • [Acute] Edaravone, glycerol, heparin: Neuroprotection and anticoagulation
  • [Chronic] DOACs or warfarin: Prevention of recurrence

Lacunar Infarction / ラクナ梗塞

• Overview
  • Small infarction in penetrating arteries of brain, leading to cerebral ischemia and necrosis
  • Common in elderly with hypertension
• Presentation
  • Mild motor weakness, sensory disturbance, dysarthria: Small vessel occlusion in penetrating artery territory
• Examination
  • [CT] Small low-density area: Small infarct in penetrating artery territory
  • [MRI] Small DWI high intensity (hyperacute), T1 low/T2 & FLAIR high intensity (acute to chronic): Small infarct in penetrating artery territory
• Management
  • [Acute] rt-PA (within 4.5h), edaravone, antiplatelet drugs: Early treatment
  • [Chronic] Antiplatelet therapy, blood pressure control: Prevention of recurrence

Transient Ischemic Attack / 一過性脳虚血発作

• Overview
  • Temporary neurological symptoms due to focal brain ischemia without infarction, important warning sign for future stroke
  • Common in patients with atherosclerosis risk factors or cardiac diseases
• Presentation
  • Sudden amaurosis fugax, weakness, hemiplegia, numbness, aphasia, dizziness (resolve in 2-15 minutes): Temporary brain or retinal ischemia
• Examination
  • [CT, MRI] No acute infarction: Differentiates from stroke
• Management
  • Antiplatelet therapy, anticooagulation: Prevention of atherothrombotic events or cardiac embolism
  • Risk factor management: Prevent recurrence

Wallenberg Syndrome / Wallenberg症候群

• Overview
  • Lateral medullary infarction due to vertebrobasilar artery occlusion
  • Common in patients with atherosclerosis risk factors or cardiac diseases
• Presentation
  • Nystagmus, vertigo, ataxia: Vestibular and cerebellar involvement
  • Ipsilateral facial sensory loss, dysphagia, hoarseness, Horner’s syndrome: Cranial nerve and sympathetic pathway involvement
  • Contralateral body temperature and pain sensory loss: Lateral spinothalamic tract involvement
  • No motor weakness or deep sensory loss: Sparing of pyramidal tract and dorsal column
• Examination
  • [CT, MRI] Stroke lesion in lateral medulla: Lateral medullary infarction
• Management
  • Treatments of atherothrombotic or cardioembolic stroke: Based on underlying cause

Cerebellar Infarction / 小脳梗塞

• Overview
  • Infarction in cerebellar territory (mainly PICA)
  • Common in patients with atherosclerosis risk factors or cardiac diseases
• Presentation
  • Sudden vertigo, nausea, vomiting, ataxia, dysarthria: Cerebellar dysfunction
  • Consciousness disturbance: Indicates brain stem compression
• Examination
  • [CT, MRI] Stroke lesion in cerebellar region: Cerebellar infarction
• Management
  • [No compression] Conservative treatment: Standard stroke care
  • [Hydrocephalus] Ventricular drainage: Relieve CSF pressure
  • [Brain stem compression] Decompressive surgery: Prevent herniation

Carotid Artery Stenosis / 頸動脈狭窄症

• Overview
  • Atherosclerotic stenosis of carotid artery, risk for cerebral infarction
  • Risk factors include hypertension, diabetes, dyslipidemia, smoking, heavy drinking
• Presentation
  • Asymptomatic: Incidental finding
  • Transient motor weakness, amaurosis fugax, hemiplegia: TIA symptoms
• Examination
  • [Ultrasound, MRI/MRA, CTA, Angiography] Carotid artery stenosis: Confirm diagnosis and assess severity
• Management
  • Risk factor control, antiplatelet drugs: Prevent strokes
  • Carotid endarterectomy (CEA), carotid artery stenting (CAS): Based on symptoms and stenosis severity

Cerebral Artery Dissection / 脳動脈解離

• Overview
  • Bleeding within walls of cerebral artery, most common in intracranial vertebral artery
  • Important cause of stroke in 40-50s
• Presentation
  • Sudden posterior neck/occipital pain: Characteristic initial symptom
  • Stroke symptoms: Due to ischemia or subarachnoid hemorrhage
• Examination
  • [MRI/MRA, DSA] Pearl and string sign, double lumen, intimal flap: Confirms diagnosis
• Management
  • [Ischemic] Anticoagulation or antiplatelet therapy: Recanalization
  • [Hemorrhagic] Trapping, proximal clipping, coil embolization: Prevent rebleeding

Putaminal Hemorrhage / 被殻出血

• Overview
  • Rupture and bleeding of lenticulostriate arteries
  • Common in patients with hypertension history
• Presentation
  • Sudden headache, consciousness disturbance: Increased intracranial pressure
  • Contralateral hemiplegia, sensory disturbance: Damage to adjacent internal capsule
  • Conjugate deviation towards lesion side: Damage to PPRF
• Examination
  • [CT] High-density area in putamen: Blood in putamen
• Management
  • Conservative treatment: For hematoma ≤30mL
  • Hematoma removal surgery: For hematoma >30mL

Thalamic Hemorrhage / 視床出血

• Overview
  • Rupture and bleeding of thalamoperforating and thalamogeniculate arteries, poor prognosis in severe cases
  • Common in patients with hypertension history
• Presentation
  • Sudden headache, consciousness disturbance: Increased intracranial pressure
  • Hemiplegia, sensory disturbance: Damage to thalamus and internal capsule
  • Downward and medial deviation of eyes: Damage to superior colliculus
• Examination
  • [CT] High-density area in thalamus: Blood in thalamus
• Management
  • Conservative treatment: Surgical intervention contraindicated due to critical location
  • Ventricular drainage: For intraventricular hemorrhage with impending herniation

Pontine Hemorrhage / 橋出血

• Overview
  • Rupture and bleeding of pontine arteries, poor prognosis in severe cases
  • Common in patients with hypertension history
• Presentation
  • Consciousness disturbance, respiratory disturbance: Direct brainstem compression
  • Quadriplegia, bilateral decerebrate rigidity: Damage to motor pathways
  • Fixed midline gaze, pinpoint pupils: Damage to PPRF and sympathetic tract
• Examination
  • [CT] High-density area in pons: Blood in pons
• Management
  • Conservative treatment: Surgical intervention contraindicated due to critical location

Cerebellar Hemorrhage / 小脳出血

• Overview
  • Rupture and bleeding of cerebellar artery (mainly SCA)
  • Common in patients with hypertension history
• Presentation
  • Sudden severe occipital headache: Direct cerebellar compression
  • Rotatory vertigo, repeated vomiting , nystagmus: Damage to cerebellar vestibular system
  • Gait disturbance without quadriplegia: Cerebellar ataxia
• Examination
  • [CT] High-density area in cerebellum: Blood in cerebellum
• Management
  • Conservative treatment: For hematoma ≤30mL
  • Hematoma removal surgery: For hematoma >30mL

Subcortical Hemorrhage / 皮質下出血

• Overview
  • Rupture and bleeding of cortical branches of cerebral arteries
  • Common in patients with arteriovenous malformation (young) or cerebral amyloid angiopathy (elderly)
• Presentation
  • Sudden headache, seizures: Increased intracranial pressure
  • Contralateral sensory disturbance: Damage to parietal lobe
  • Homonymous hemianopia: Damage to occipital lobe
  • Sensory aphasia, visual field defect: Damage to temporal lobe
  • Contralateral motor paralysis: Damage to frontal lobe
• Examination
  • [CT] High-density area in subcortical region: Blood in affected lobe
• Management
  • Conservative treatment: For hematoma with depth >1cm from surface
  • Hematoma removal surgery: For hematoma with depth ≤1cm from surface

Cerebral Aneurysm / 脳動脈瘤

• Overview
  • Bulging of cerebral arteries due to medial defects and acquired factors, causes subarachnoid hemorrhage when ruptured
  • More common in 40-60 years adults
• Presentation
  • Asymptomatic: Found incidentally
  • Pupil dilation, diplopia, ptosis: IC-PC aneurysm compressing cranial nerve III
  • Visual disturbance: IC-Oph aneurysm compressing cranial nerve II
• Examination
  • [MRA, 3D-CTA, DSA] Visible aneurysm: Confirms diagnosis and location
• Management
  • Surgical neck clipping, endovascular coil embolization: For symptomatic or high risk aneurysm
  • Observation, blood pressure control, lifestyle modification: For asymptomatic and small aneurysm

Subarachnoid Hemorrhage / くも膜下出血

• Overview
  • Bleeding into subarachnoid space from ruptured cerebral aneurysm or AVM, rapid progression and high mortality
  • More common in 40-60 years adults
• Presentation
  • Thunderclap headache: Rupture of cerebral aneurysm
  • Nausea, vomiting, altered consciousness, seizures: Increased intracranial pressure
  • Neck stiffness, Kernig’s sign: Meningeal irritation
• Examination
  • [CT] Starfish-shaped high density in suprasellar region: Bleeding in subarachnoid space
  • [MRI] FLAIR high signal in subarachnoid space: When CT is negative
  • [CSF] Bloody or xanthochromic: When CT, MRI are negative
  • [DSA, 3D-CTA, MRA] Identify bleeding source: Pre-surgical planning
• Management
  • [Pre-op] Blood pressure control, anti-edema drugs, sedation, anticonvulsants: Prevent rebleeding and herniation
  • [Definitive] Surgical neck clipping, endovascular coil embolization: Repair ruptured cerebral arteries
  • [Post-op] Fasudil, ozagrel sodium, Triple-H therapy: Prevent/treat vasospasm

Arteriovenous Malformation / 脳動静脈奇形

• Overview
  • Congenital vascular malformation with direct arteriovenous shunting and abnormal vessel cluster (nidus)
  • More common children and young adults
• Presentation
  • Headache, seizures, progressive hemiparesis: Cerebral ischemia due to steal phenomenon
  • Sudden headache, hemiparesis, altered consciousness: Intracerebral hemorrhage
  • Neck stiffness, Kernig’s sign: Subarachnoid hemorrhage
• Examination
  • [DSA, MRA] Dilated and tortuous vessels with nidus: Abnormal vascular connections
  • [MRI] Multiple flow voids: Rapid flow rate in nidus
• Management
  • Surgical excision, endovascular embolization, stereotactic radiosurgery: For hemorrhagic or progressive cases
  • Conservative treatment: For non-hemorrhagic or inoperable cases

Moyamoya Disease / もやもや病

• Overview
  • Progressive stenosis/occlusion of bilateral ICA terminus, causing formation of fragile collateral vessels
  • Common in children <10y and adults 30-40y
• Presentation
  • Transient hemiparesis, altered consciousness, speech disturbance after hyperventilation (in children): Cerebral ischemia
  • Focal neurological deficits (in adults): Intracerebral hemorrhage or ischemia
• Examination
  • [MRA, DSA] Bilateral stenosis of ICA terminus and proximal ACA/MCA, abnormal vessel network: Characteristic moyamoya vessels
  • [MRI] Flow voids in bilateral basal ganglia: Rapid flow rate in collateral vessels
• Management
  • STA-MCA anastomosis, EMS, EDAS: Improve blood flow by direct and indirect bypass
  • Antiplatelet drugs, anticonvulsants: Conservative treatment

Carotid-Cavernous Fistula / 内頸動脈-海綿静脈洞瘻

• Overview
  • Abnormal connection between internal carotid artery and cavernous sinus
  • Due to trauma or aneurysm rupture
• Presentation
  • Pulsatile exophthalmos, conjunctival congestion/edema, orbital bruit: High pressure in cavernous sinus causing venous congestion
  • Diplopia, visual disturbance: Extraocular muscle palsy due to cranial nerve compression
• Examination
  • [DSA] Early visualization of cavernous sinus in arterial phase: Direct arteriovenous shunting
• Management
  • Endovascular surgery: Close fistula

Cerebral Venous Sinus Thrombosis / 脳静脈洞血栓症

• Overview
  • Thrombosis in cerebral venous sinuses leading to venous congestion
  • Associated with pregnancy/puerperium, oral contraceptives, autoimmune diseases, blood disorders, infections
• Presentation
  • Severe headache, vomiting: Increased intracranial pressure
  • Seizures, weakness, paralysis, altered consciousness: Brain edema or hemorrhage
• Examination
  • [MRI] Brain hemorrhage, edema: Due to venous congestion
  • [MRV] Venous sinus occlusion: Direct visualization of thrombus
• Management
  • Heparin: Prevent thrombus progression

Normal Pressure Hydrocephalus / 正常圧水頭症

• Overview
  • Chronic hydrocephalus with normal CSF pressure due to circulation disturbance in subarachnoid space
  • Idiopathic (60-70s) or secondary to SAH, trauma, meningitis
• Presentation
  • Gait disturbance, cognitive decline, urinary incontinence: Due to enlarged ventricles compressing brain tissue
• Examination
  • [CT/MRI] Symmetrical ventricular enlargement, dilated Sylvian fissures and basal cisterns: Hydrocephalus involving ventricles and subarachnoid space
  • [Lumbar puncture] Normal CSF pressure: Distinguishes from other types of hydrocephalus
• Management
  • Lumboperitoneal (L-P) or ventriculoperitoneal (V-P) shunt: Divert excess CSF

Dementia / 認知症

Alzheimer’s Disease / Alzheimer型認知症

• Overview
  • Most common type of dementia, neurodegenerative disease characterized by brain atrophy and presence of senile plaques and neurofibrillary tangles
  • Common in elderly
• Presentation
  • Memory loss, disorientation, impaired judgment: Hippocampal and temporal lobe atrophy
  • Apraxia, agnosia, aphasia, executive dysfunction: Parietal lobe atrophy
  • Delusions (theft), behavioral changes: Progressive cognitive decline
• Examination
  • [CT/MRI] Cortical atrophy (hippocampus), enlarged sulci and ventricles: General brain atrophy
  • [SPECT/PET] Decreased blood flow in parietal and temporal lobes: Reduced brain function
  • [Cognitive tests] Decline in memory and cognitive function: Progressive cognitive decline
• Management
  • Cholinesterase inhibitors (donepezil), NMDA receptor antagonist (memantine): Improve cognitive function or reduce cognitive decline
  • Atypical antipsychotics, yokukansan: Manage psychiatric symptoms
  • Exercise, reminiscence therapy, recreation, music therapy: Non-pharmacological therapy

Dementia with Lewy Bodies / Lewy小体型認知症

• Overview
  • Neurodegenerative disease characterized by cognitive impairment, visual hallucinations, and parkinsonism
  • Common in elderly
• Presentation
  • Fluctuating cognitive impairment: Progressive neurodegeneration
  • Recurrent visual hallucinations: May due to occipital lobe dysfunction
  • Parkinsonism: Due to dopaminergic neuron loss
  • REM sleep behavior disorder: Disruption of muscle tone in sleep
• Examination
  • [SPECT/PET] Decreased occipital blood flow: Reduced brain function
  • [MIBG myocardial scintigraphy] Decreased MIBG uptake: Sympathetic denervation
  • [DAT-SPECT] Reduced striatal uptake: Loss of dopaminergic neurons
• Management
  • Cholinesterase inhibitors (donepezil): Improve cognitive function
  • Yokukansan, atypical antipsychotics: Manage hallucinations (antipsychotics may worsen parkinsonism)
  • L-dopa: Treat parkinsonism
  • Clonazepam: Treat REM sleep behavior disorder

Frontotemporal Dementia / 前頭側頭型認知症

• Overview
  • Neurodegenerative disease characterized by personality changes and behavioral abnormalities
  • Common in middle-aged adults (40-60s)
• Presentation
  • Decreased initiative, emotional blunting: Frontal lobe atrophy
  • Disinhibition, stereotypical behaviors, lack of disease awareness: Behavioral changes
• Examination
  • [CT/MRI] Frontal and temporal lobe atrophy: Localized brain degeneration
  • [SPECT/PET] Decreased blood flow in frontal and temporal lobes: Reduced brain function
• Management
  • Symptomatic treatment: No curative treatment

Vascular Dementia / 血管性認知症

• Overview
  • Second most common type of dementia, caused by cerebrovascular disorders including infarctions and hemorrhages
  • Risk factors: hypertension, diabetes, dyslipidemia, atrial fibrillation, smoking
• Presentation
  • Depression, reduced spontaneity, executive dysfunction, delirium, emotional incontinence: Damage to various brain regions
  • Patchy cognitive decline: Specific cognitive decline based on lesion area
  • Motor/sensory deficits, pseudobulbar palsy, parkinsonian gait: Focal neurological symptoms based on lesion area
• Examination
  • [CT/MRI] Infarcts, hemorrhages: Evidence of cerebrovascular disease
• Management
  • Blood pressure control, antiplatelet/anticoagulation therapy: Prevent stroke recurrence
  • Rehabilitation, lifestyle modification: Improve functional status

Neurodegenerative Disorder / 神経変性疾患

Parkinson’s Disease / Parkinson病

• Overview
  • Neurodegenerative disorder due to loss of dopamine-producing cells in substantia nigra
  • Common in middle-aged and elderly
• Presentation
  • Resting tremor (4-6 Hz): Reduced dopamine transmission
  • Bradykinesia, micrographia, mask-like face: Impaired movement initiation
  • Muscle rigidity (cogwheel or lead-pipe): Increased muscle tone
  • Postural instability, forward-leaning posture: Impaired balance control
  • Freezing gait, small steps, festination: Combined effect of bradykinesia and postural instability
  • Constipation, urinary dysfunction, orthostatic hypotension, seborrhea: Autonomic dysfunction
• Examination
  • [MIBG myocardial scintigraphy] Reduced MIBG uptake: Sympathetic denervation
  • [DAT-SPECT] Reduced striatal uptake: Loss of dopaminergic neurons
• Management
  • L-dopa: Replaces dopamine
  • Dopamine agonists: Stimulates dopamine receptors
  • Anticholinergics, amantadine, MAO-B inhibitors, COMT inhibitors: Various mechanisms to improve dopamine function
  • Deep brain stimulation: For medication-resistant cases

Progressive Supranuclear Palsy / 進行性核上性麻痺

• Overview
  • Progressive neurodegenerative disease with tau protein accumulation in basal ganglia and brainstem
  • Common in males aged 50-70 years
• Presentation
  • Vertical gaze palsy (especially downward): Supranuclear impairment of vertical eye movements
  • Early falls, postural instability, neck extension: Increased axial muscle tone
  • Bradykinesia, masked face, small voice, freezing gait: Parkinsonism (rare resting tremor)
  • Dysarthria, dysphagia: Pseudobulbar palsy
  • Subcortical dementia: Cognitive decline
• Examination
  • [CT/MRI] Midbrain tegmentum atrophy (hummingbird sign): Characteristic neurodegeneration pattern
• Management
  • Supportive care: No established treatment
  • Levodopa, other antiparkinsonian drugs: Limited effectiveness

Corticobasal Degeneration / 大脳皮質基底核変性症

• Overview
  • Progressive neurodegenerative disease with tau protein accumulation in cerebral cortex and basal ganglia
  • Common in ages 50-70 years
• Presentation
  • Limb-kinetic apraxia, ideomotor apraxia, alien hand syndrome , cortical sensory loss: Cortical symptoms
  • Rigidity, bradykinesia, postural instability: Parkinsonism (rare resting tremor)
  • Myoclonus, dystonia, cognitive decline: Other brain involvement
  • Symptoms show marked asymmetry: Characteristic feature
• Examination
  • [CT/MRI] Asymmetric cerebral atrophy: Underlying neurodegeneration
• Management
  • Supportive care: No established treatment
  • Levodopa, other antiparkinsonian drugs: Limited effectiveness

Huntington’s Disease / Huntington病

• Overview
  • Progressive neurodegenerative disease due to CAG repeat expansion in Huntington gene
  • Autosomal dominant , onset typically 30-50 years
• Presentation
  • Quick, dance-like involuntary movements of limbs: Chorea due to striatal degeneration
  • Personality changes, dementia, delusions, hallucinations: Progressive psychiatric symptoms
• Examination
  • [CT/MRI] Caudate nucleus atrophy, enlarged anterior horn of lateral ventricles: Characteristic brain changes
  • [Genetic test] CAG repeat expansion in Huntington gene: Confirms diagnosis
• Management
  • Haloperidol, tiapride, tetrabenazine: Control chorea (levodopa worsens symptoms)
  • Haloperidol, chlorpromazine: Manage psychiatric symptoms

MSA-C / 多系統萎縮症小脳型

• Overview
  • Progressive degeneration of inferior olive nucleus, pons, and cerebellum
  • Common in middle-aged and elderly, non-hereditary
• Presentation
  • Truncal ataxia, drunken gait, limb incoordination, dysarthria: Cerebellar dysfunction (initial symptoms)
  • Abnormal finger-nose, heel-knee, diadochokinesis tests: Cerebellar dysfunction
  • Parkinsonism, autonomic symptoms, pyramidal signs: Disease progression affecting multiple systems
• Examination
  • [CT/MRI] Cerebellar and brainstem atrophy: Neurodegeneration
  • [MRI T2] Hot cross bun sign in ventral pons: Characteristic finding of MSA-C
• Management
  • TRH/TRH derivatives: For cerebellar symptoms
  • Levodopa: For parkinsonism
  • Droxidopa, midodrine, α-blockers: For autonomic symptoms (orthostatic hypotension, urinary dysfunction)

MSA-P / 多系統萎縮症パーキンソン型

• Overview
  • Progressive degeneration of striatum and substantia nigra
  • Common in middle-aged and elderly, non-hereditary
• Presentation
  • Akinesia, rigidity, small-step gait: Parkinsonian symptoms (rare resting tremor)
  • Cerebellar symptoms, autonomic symptoms, pyramidal signs: Disease progression affecting multiple systems
• Examination
  • [MRI] Putaminal atrophy: Striatal degeneration
  • [MRI T2/FLAIR] Linear hyperintensity in lateral putamen: Characteristic finding of MSA-P
• Management
  • Levodopa: For parkinsonism
  • TRH/TRH derivatives: For cerebellar symptoms
  • Droxidopa, midodrine, α-blockers: For autonomic symptoms (orthostatic hypotension, urinary dysfunction)

Shy-Drager Syndrome / Shy-Drager症候群

• Overview
  • Part of multiple system atrophy characterized by primary autonomic dysfunction
  • Common in middle-aged and elderly, non-hereditary
• Presentation
  • Orthostatic hypotension, postprandial hypotension, urinary dysfunction, constipation, erectile dysfunction, anhidrosis, Horner’s syndrome: Autonomic dysfunction
  • Cerebellar symptoms, parkinsonism, pyramidal signs: Disease progression affecting multiple systems
• Examination
  • [CT/MRI] Various combinations of MSA-C and MSA-P findings: Multiple system involvement
• Management
  • Droxidopa, midodrine, α-blockers: For autonomic symptoms (orthostatic hypotension, urinary dysfunction)
  • TRH/TRH derivatives: For cerebellar symptoms
  • Levodopa: For parkinsonism

Amyotrophic Lateral Sclerosis / 筋萎縮性側索硬化症

• Overview
  • Progressive degeneration of both upper and lower motor neurons leads to muscle atrophy
  • Common in 60-70s, mainly sporadic but some familial
• Presentation
  • Muscle weakness, atrophy, fasciculation (mainly upper limbs): Lower motor neuron damage
  • Hyperreflexia, Babinski sign (mainly lower limbs): Upper motor neuron damage
  • Dysphagia, dysarthria, tongue atrophy: Bulbar palsy
  • No eye movement disorder, sensory disturbance, bladder/bowel dysfunction, pressure sores: Four negative symptoms characteristic of ALS
• Examination
  • [EMG] Denervation potentials at rest, high amplitude potentials during voluntary contraction: Neurogenic changes
  • [Muscle ultrasound] Fasciculation: Lower motor neuron damage
• Management
  • Supportive care, rehabilitation: No curative treatment , mean survival 3-5 years
  • Riluzole, edaravone: Limited effectiveness

Spinal Muscular Atrophy / 脊髄性筋萎縮症

• Overview
  • Degeneration of lower motor neurons due to SMN gene deletion/mutation, four types based on age of onset and severity
• Presentation
  • [Type I] Severe hypotonia (floppy infant): Onset at birth
  • [Type II] Intermediate severity: Onset by age 2
  • [Type III] Proximal muscle weakness, Gowers’ sign: Onset age 2-18
  • [Type IV] Very slow progression: Adult onset
  • Normal intelligence: Only motor function affected
• Examination
  • [Genetic testing] SMN gene deletion/mutation: Confirms diagnosis in many cases
• Management
  • Supportive care: No curative treatment, variable progression based on types

Bulbospinal Muscular Atrophy / 球脊髄性筋萎縮症

• Overview
  • Degeneration of lower motor neurons due to CAG repeat expansion in androgen receptor gene
  • X-linked recessive, common in 20-50 years males
• Presentation
  • Bulbar palsy, widespread fasciculations: Lower motor neuron degeneration
  • Gynecomastia, hypogonadism: Androgen receptor dysfunction
  • Normal intelligence: Only motor and endocrine systems affected
• Examination
  • [Genetic testing] CAG repeat expansion in androgen receptor gene: Definitive diagnosis
• Management
  • Supportive care: No curative treatment, slow progression

Demyelinating Disorder / 脱髄性疾患

Multiple Sclerosis / 多発性硬化症

• Overview
  • Autoimmune demyelinating disease affecting central nervous system white matter
  • Multiple lesions occur in space and time with relapsing-remitting course
  • Common in women aged 15-50
• Presentation
  • Sudden visual impairment, central scotoma: Retrobulbar optic neuritis
  • Double vision, MLF syndrome: Brainstem involvement
  • Muscle weakness, hyperreflexia, Babinski sign: Pyramidal tract involvement
  • Numbness, trigeminal neuralgia, Lhermitte’s sign: Sensory tract involvement
  • Ataxia, tremor, nystagmus, dysarthria: Cerebellar involvement
  • Neurogenic bladder: Autonomic system involvement
  • Euphoria, depression: Mental symptoms
• Examination
  • [MRI] Multiple white matter lesions: Spatial dissemination
  • [CSF] IgG↑, oligoclonal bands, MBP↑: Psychiatric destruction
• Management
  • [Acute] Steroid pulse therapy, plasmapheresis: Reduce inflammation
  • [Prevention] IFN-β, glatiramer acetate, fingolimod, natalizumab: Prevent relapses
  • [Symptomatic] Gabapentin/pregabalin (pain), carbamazepine (spasm), baclofen (spasticity): Manage symptoms

Neuromyelitis Optica / 視神経脊髄炎

• Overview
  • Autoimmune disease with antibodies against aquaporin-4 (AQP4) in astrocytes
  • Common in 30s women, often associated with other autoimmune diseases
• Presentation
  • Visual loss, blindness, horizontal hemianopia: Severe optic neuritis
  • Quadriparesis, sensory disturbance, bladder/bowel dysfunction: Transverse myelitis
• Examination
  • [MRI] Extensive spinal cord lesions (≥3 vertebral segments): Extensive transverse myelitis
  • [Blood] Anti-AQP4 antibody positive: Confirms diagnosis
  • [CSF] Oligoclonal bands usually negative: Differentiate from MS
• Management
  • [Acute] Steroid pulse therapy, plasmapheresis: Reduce inflammation
  • [Prevention] Steroids, immunosuppressants, rituximab: Prevent relapses

Acute Disseminated Encephalomyelitis / 急性散在性脳脊髄炎

• Overview
  • Inflammatory demyelinating disease of central nervous system, similar to MS but with rapid onset and remission
  • Common in children, triggered by viral infections or vaccines
• Presentation
  • Sudden onset of headache, vomiting, consciousness disturbances, seizures: Acute disseminated demyelination of central nervous system
• Examination
  • [MRI] Multiple demyelinating lesions: Similar to MS but typically monophasic
• Management
  • High-dose steroids, immunoglobulin: Reduce inflammation
  • Good prognosis: Usually monophasic

Miscellaneous CNS Disorder / その他の中枢神経疾患

Anti-NMDA Receptor Encephalitis / 抗NMDA受容体抗体脳炎

• Overview
  • Autoimmune encephalitis mainly affecting limbic system through anti-NMDA receptor antibodies
  • Common in young females, associated with tumors especially ovarian teratoma
• Presentation
  • Fever, headache: Prodromal phase
  • Agitation, hallucinations, delusions: Psychiatric phase
  • Decreased consciousness, reduced movement, respiratory depression: Unresponsive phase
  • Dystonia, orofacial dyskinesia, myoclonus, seizures: Movement disorder phase
• Examination
  • [Blood/CSF] Anti-NMDA receptor antibodies: Confirms diagnosis
  • [MRI] Abnormal signals in limbic system: Inflammation in limbic system
• Management
  • Tumor removal: If present
  • Steroid pulse therapy, IVIg, plasmapheresis: Suppress immune response

Wernicke’s Encephalopathy / Wernicke脳症

• Overview
  • Acute/subacute inflammation and necrosis in periventricular areas due to vitamin B1 deficiency
  • Often seen in alcoholism, post-gastrointestinal surgery, hyperemesis gravidarum
• Presentation
  • Altered consciousness, delirium, confusion: Thalamus involvement
  • Eye movement disorders, nystagmus: Brainstem involvement
  • Trunk ataxia, unsteady gait: Cerebellar dysfunction
• Examination
  • [MRI] T2/FLAIR high signal in periventricular areas: Periventricular inflammation and necrosis
  • [Blood] Low vitamin B1, lactic acidosis: Thiamine deficiency and metabolic derangement
• Management
  • Immediate high-dose IV thiamine (before glucose administration): Replace deficiency
  • May progress to Korsakoff syndrome: Amnesia, disorientation, confabulation

Subacute Combined Degeneration of Spinal Cord / 亜急性脊髄連合変性症

• Overview
  • Vitamin B12 deficiency causing degeneration of peripheral and central nervous system
  • Common after total gastrectomy due to malabsorption of B12
• Presentation
  • Macrocytic anemia, Hunter glossitis: Vitamin B12 deficiency
  • Romberg sign, impaired proprioception: Posterior column damage
  • Hyperreflexia, Babinski sign, spastic paralysis: Lateral column (pyramidal tract) damage
  • Numbness and weakness in extremities: Peripheral nerve damage
• Examination
  • [Blood] Vitamin B12↓, methylmalonic acid↑, homocysteine↑: B12 deficiency disrupts folate and fatty acid metabolism
  • [Urine] Methylmalonic acid excretion↑: Same
• Management
  • Intramuscular vitamin B12: Replace deficiency
  • Avoid folic acid alone: Can worsen neurological symptoms

Spinal Cord Infarction / 脊髄梗塞

• Overview
  • Infarction of anterior 2/3 of spinal cord due to anterior spinal artery occlusion
  • Common causes: Aortic dissection, aortic surgery, atherosclerosis
• Presentation
  • Motor weakness, sensory loss (pain, temperature): Anterior and lateral columns involvement
  • Preserved position/vibration sense: Posterior column sparing
• Examination
  • [MRI] T2 high signal in anterior spinal cord: Anterior spinal cord infarction
• Management
  • Edaravone, anti-edema drugs, corticosteroids: Neuroprotection

Spinal Arteriovenous Malformation / 脊髄動静脈奇形

• Overview
  • Abnormal arteriovenous shunts in spinal cord vasculature, classified as intramedullary AVM, perimedullary AVF, dural AVF
• Presentation
  • Acute motor and sensory disturbances, headache, vomiting, consciousness disturbances: Acute intramedullary or subarachnoid hemorrhage
  • Gradual motor and sensory disturbances: Venous hypertension causes congestion and edema in spinal cord
• Examination
  • [MRI] Flow void lesions of nidus or shunt, T2 high signal in spinal cord: Arteriovenous malformation, spinal edema
  • [Angiography] Nidus, shunt: Definitive diagnosis
• Management
  • [Surgical treatment]: Direct removal of AVM/AVF
  • [Endovascular treatment]: Catheter-based embolization

Syringomyelia / 脊髄空洞症

• Overview
  • Fluid-filled cavity formation within spinal cord causing neurological deficits
  • Common in 20-40s, often associated with Chiari malformation
• Presentation
  • Upper limb temperature and pain sensory loss (unilateral first and bilateral cape-like later): Damage to spinothalamic tract (central spinal cord)
  • Upper limb muscle atrophy, lower limb spastic paralysis: Progress to involve anterior horn and lateral column
  • Bulbar palsy, Horner’s syndrome: Progress to involve upper and lower levels of spinal cord
• Examination
  • [MRI] Cavity formation within spinal cord: Confirm diagnosis
• Management
  • Foramen magnum decompression: Primary treatment for Chiari-associated cases
  • Syrinx-subarachnoid shunt: Direct treatment of syrinx

Brown-Séquard Syndrome / Brown-Séquard症候群

• Overview
  • Hemisection of spinal cord resulting in distinct neurological deficits
  • Causes include trauma, tumor, infection
• Presentation
  • [At level of injury] Ipsilateral all sensory loss: Damage to dorsal root entry
  • [At level of injury] Ipsilateral muscle weakness: Damage to anterior horn exit
  • [Below level of injury] Ipsilateral proprioceptive loss: Damage to dorsal column before crossing
  • [Below level of injury] Ipsilateral spastic paralysis: Damage to pyramidal tract after crossing
  • [Below level of injury] Contralateral pain and temperature loss: Damage to lateral spinothalamic tract after crossing
• Examination
  • [Physical] Characteristic sensory and motor loss
• Management
  • Treat underlying cause

Peripheral Nerve Disorder / 末梢神経障害

Guillain-Barré Syndrome / Guillain-Barré症候群

• Overview
  • Acute immune-mediated polyneuropathy affecting myelin/axons of peripheral nerves, generally self-limiting but can be severe
  • Usually preceded by respiratory or gastrointestinal infection
• Presentation
  • Ascending symmetric flaccid paralysis, respiratory difficulty (severe cases): Lower motor neuron damage
  • Sensory disturbances in limbs, decreased tendon reflexes: Peripheral nerve dysfunction
  • Facial paralysis, bulbar palsy, diplopia: Cranial nerve involvement
• Examination
  • [Blood] Anti-ganglioside antibodies (anti-GM1): Autoimmune nature
  • [CSF] Protein↑, cell→: Inflammation but no infection
  • [Nerve conduction] Decreased conduction velocity, conduction block: Demyelination/axonal damage
• Management
  • [Mild] Conservative treatment: Self-limiting nature
  • [Moderate] IV immunoglobulin, plasma exchange: Modulate immune response
  • [Severe] Respiratory support: For respiratory muscle paralysis

Chronic Inflammatory Demyelinating Polyradiculoneuropathy / 慢性炎症性脱髄性多発根ニューロパチー

• Overview
  • Chronic autoimmune demyelinating peripheral neuropathy
  • Progress over >2 months, no preceding infection
• Presentation
  • Progressive weakness and sensory disturbances in limbs, decreased tendon reflexes: Demyelination of peripheral nerves
• Examination
  • [Nerve conduction] Decreased conduction velocity, conduction block: Demyelination
  • [CSF] Protein↑, cell→: Inflammation but no infection
  • [MRI] Thickening and enhancement of nerve roots and plexus: Chronic inflammation of nerve roots
  • [Nerve biopsy] Demyelination, remyelination, inflammatory cell infiltration: Confirms diagnosis
• Management
  • Corticosteroids, IV immunoglobulin, plasma exchange: Modulate immune response

Charcot-Marie-Tooth Disease / Charcot-Marie-Tooth病

• Overview
  • Hereditary progressive peripheral neuropathy caused by mutations in myelin-related genes
  • Autosomal dominant inheritance, onset in 10-30s
• Presentation
  • Distal leg weakness, calf atrophy (drop foot), gait disturbance (steppage gait): Progressive motor neuropathy
  • Mild sensory disturbance, decreased tendon reflexes: Peripheral nerve dysfunction
• Examination
  • [Nerve conduction] Decreased conduction velocity: Demyelination
  • [Genetic testing] Myelin-related genes mutation: Confirms diagnosis
  • [Nerve biopsy] Onion bulb formation: Chronic demyelination and remyelination
• Management
  • Supportive care: No specific treatment available
  • Good life prognosis: Very slow progression