Essences of clinical medicine.

Cardiology / 循環器科

Pulmonology/ 呼吸器科

Respiratory Failure / 呼吸不全

Respiratory Failure / 呼吸不全

• Overview
  • Inability of respiratory system to maintain adequate gas exchange, resulting in hypoxemia (Type I) and/or hypercapnia (Type II)
  • Can occur at any age, various underlying causes (pneumonia, COPD, pulmonary edema, etc.)
  • May present acutely or develop chronically, can be life-threatening without prompt treatment
• Presentation
  • Dyspnea, tachypnea, use of accessory muscles: Compensatory response to inadequate gas exchange and increased work of breathing
  • Cyanosis (central and peripheral): Inadequate oxygenation leading to increased deoxygenated hemoglobin
  • Altered mental status, confusion, somnolence: Hypoxemia and hypercapnia affecting cerebral function
• Examination
  • [ABG] PaO2 < 60 mmHg (Type I), PaCO2 > 45 mmHg (Type II), pH changes: Direct measurement of gas exchange failure
  • [Pulse oximetry] SpO2 < 90%: Non-invasive assessment of oxygenation status
  • [Chest X-ray/CT] Pulmonary infiltrates, pleural effusion, pneumothorax: Identify underlying pulmonary pathology
• Management
  • Oxygen therapy (nasal cannula, face mask, high-flow): Improve oxygenation and tissue oxygen delivery
  • Non-invasive ventilation (BiPAP, CPAP): Support ventilation while avoiding intubation
  • Mechanical ventilation (invasive): Provide complete respiratory support in severe cases
  • Treat underlying cause (antibiotics, bronchodilators, diuretics): Address specific etiology causing respiratory failure

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

• Overview
  • Non-cardiogenic pulmonary edema due to increased pulmonary capillary permeability from inflammatory response triggered by direct or indirect lung injury
  • Commonly in ICU settings with various precipitating factors (sepsis, pneumonia, trauma, aspiration)
  • Acute onset with rapid progression, high mortality rate (30-40%)
• Presentation
  • Severe dyspnea, tachypnea: Impaired gas exchange due to alveolar epithelial/endothelial damage and ventilation-perfusion mismatch
  • Hypoxemia refractory to supplemental oxygen: Intrapulmonary shunting through flooded alveoli and ventilation-perfusion mismatch
  • Cyanosis, restlessness: Severe hypoxemia and hypoxia
• Examination
  • [ABG] PaO2/FiO2 ratio <300 (mild), <200 (moderate), <100 (severe), initially respiratory alkalosis then metabolic acidosis: Impaired oxygenation and CO2 retention
  • [CXR] Bilateral pulmonary infiltrates: Non-cardiogenic pulmonary edema
  • [CT] Bilateral ground-glass opacities, consolidation, dependent atelectasis: Inflammatory fluid accumulation and alveolar collapse
  • [Echocardiography] Normal left atrial pressure, PCWP <18 mmHg: Rule out cardiogenic pulmonary edema
• Management
  • Mechanical ventilation with lung-protective strategy: Prevent ventilator-induced lung injury while maintaining adequate ventilation
  • Positive end-expiratory pressure (PEEP): Recruit collapsed alveoli and improve oxygenation
  • Prone positioning: Improve ventilation-perfusion matching in posterior lung regions
  • Treat underlying cause (antibiotics for sepsis, supportive care): Address precipitating factors

Obstructive Lung Disease / 閉塞性肺疾患

Asthma / 喘息

• Overview
  • Chronic inflammatory airway disease characterized by reversible airway obstruction, airway hyperresponsiveness, and airway remodeling
  • Common in children and adults, often associated with atopy and family history of allergic diseases
  • Chronic condition with episodic exacerbations triggered by allergens, infections, exercise, or irritants
• Presentation
  • Wheezing, shortness of breath, chest tightness: Bronchoconstriction and airway narrowing due to smooth muscle contraction and mucosal edema
  • Dry cough (often worse at night or early morning): Airway inflammation and hyperresponsiveness to stimuli
  • Exercise intolerance: Exercise-induced bronchoconstriction due to airway cooling and drying
  • Symptom variability: Symptoms fluctuate with triggers and time
• Examination
  • [Pulmonary Function Test] FEV1↓, FEV1/FVC ratio↓, reversibility >12% after bronchodilator: Airway obstruction that improves with bronchodilation
  • [Peak Flow] Reduced peak expiratory flow rate, diurnal variation >20%: Variable airway obstruction throughout the day
  • [Blood] Eosinophilia, elevated total IgE, specific IgE to allergens: Allergic inflammation and type I hypersensitivity reaction
• Management
  • Short-acting β2-agonists (SABA): Relax bronchial smooth muscle for quick relief of bronchoconstriction
  • Inhaled corticosteroids (ICS): Reduce chronic airway inflammation and prevent exacerbations
  • Long-acting β2-agonists (LABA) + ICS combination: LABA provides sustained bronchodilation, ICS controls inflammation
  • Leukotriene receptor antagonists (LTRA): Block inflammatory mediators, especially useful in aspirin-sensitive or exercise-induced asthma
  • Anti-IgE therapy: Bind free IgE for severe allergic asthma
  • Allergen avoidance, trigger identification: Prevent exposure to known triggers to reduce exacerbation frequency

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

• Overview
  • Progressive airway obstruction due to chronic inflammation, usually from smoking
  • Includes emphysema (alveolar destruction) and chronic bronchitis (airway inflammation and mucus hypersecretion)
  • Commonly in older adults, especially smokers and those with occupational dust exposure
  • Progressive, irreversible course with acute exacerbations
• Presentation
  • Dyspnea (initially on exertion, progressing to rest), exercise intolerance: Airway obstruction and impaired gas exchange reduce oxygen delivery
  • Chronic productive cough with sputum: Chronic bronchitis component causes mucus hypersecretion and impaired clearance
  • Barrel chest, use of accessory muscles, pursed-lip breathing: Hyperinflation and increased work of breathing due to air trapping
  • Weight loss (advanced cases): Increased metabolic demand from respiratory work and systemic inflammation
• Examination
  • [Physical] Decreased breath sounds, wheezing, hyperresonance: Airway obstruction and hyperinflation
  • [Pulmonary Function] FEV1/FVC < 0.7, TLC↑, RV↑: Airway obstruction and air trapping
  • [Chest X-ray/CT] Hyperinflation, flattened diaphragm, bullae: Emphysematous changes and air trapping
  • [ABG] PaO2↓, PaCO2↑ (advanced): Ventilation-perfusion mismatch and alveolar hypoventilation
• Management
  • Smoking cessation: Prevent further lung damage and slow disease progression
  • Short-acting bronchodilators (SABA, SAMA): Relieve acute bronchospasm by β2-agonism and anticholinergic action
  • Long-acting bronchodilators (LABA, LAMA): Maintain bronchodilation and reduce exacerbations
  • Inhaled corticosteroids (ICS): Reduce airway inflammation, especially in frequent exacerbators
  • Oxygen therapy (long-term): Correct hypoxemia and prevent cor pulmonale in severe cases
  • Pulmonary rehabilitation: Improve exercise tolerance and quality of life through physical training
  • [Acute exacerbation] Systemic corticosteroids, antibiotics, non-invasive ventilation: Reduce inflammation, treat bacterial infection, support ventilation

Bronchiectasis / 気管支拡張症

• Overview
  • Irreversible dilation and distortion of bronchi and bronchioles due to chronic infection and inflammation, leading to impaired clearance mechanisms
  • Can be congenital (cystic fibrosis, primary ciliary dyskinesia) or acquired (post-infectious, immune deficiency, aspiration)
  • Progressive chronic condition with recurrent exacerbations
• Presentation
  • Chronic productive cough with purulent sputum, recurrent respiratory infections: Impaired mucociliary clearance and bacterial colonization in dilated airways
  • Dyspnea on exertion, wheezing: Airflow obstruction due to bronchial wall thickening and secretions
  • Hemoptysis: Chronic inflammation leads to hypervascular bronchial circulation and vessel rupture
• Examination
  • [Blood] WBC↑, CRP↑ (during exacerbations): Acute on chronic infection
  • [Sputum culture] Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae: Common bacterial colonization in damaged airways
  • [Pulmonary function tests] FEV1↓, FEV1/FVC ratio↓: Obstructive pattern due to airway narrowing
  • [Chest X-ray] Crowded bronchi (tramlines), ring shadows, volume loss: Structural changes and scarring
  • [High-resolution CT] Bronchial dilation, bronchial wall thickening, cystic changes: Gold standard showing structural changes and active infection
• Management
  • Airway clearance techniques (chest physiotherapy, oscillatory devices), mucolytics: Enhance secretion removal from dilated airways
  • Bronchodilators (β2-agonists, anticholinergics): Relax airway smooth muscle to improve airflow
  • Antibiotics (oral for mild exacerbations, IV for severe): Treat bacterial infections and reduce inflammation
  • Anti-inflammatory drugs (inhaled corticosteroids, macrolides): Reduce airway inflammation and frequency of exacerbations

Interstitial Lung Disease / 間質性肺疾患

Idiopathic Pulmonary Fibrosis / 特発性肺線維症

• Overview
  • Progressive, irreversible fibrotic disease of lung parenchyma of unknown etiology, characterized by usual interstitial pneumonia (UIP) pattern
  • Most common in male adults >50 years old, associated with smoking and environmental exposures
  • Progressive course with median survival of 2-5 years from diagnosis
• Presentation
  • Progressive dyspnea on exertion, eventually at rest: Fibrosis reduces lung compliance and impairs gas exchange
  • Dry nonproductive cough: Irritation from fibrotic changes and distortion of lung architecture
  • Fine inspiratory crackles: Opening of fibrotic alveoli during inspiration
  • Digital clubbing: Chronic hypoxemia leads to vascular changes in fingertips
• Examination
  • [Blood] LDH↑, KL-6↑, SP-A↑, SP-D↑: Pneumocyte damage release these biomarkers
  • [PFT] FVC↓, FEV1↓, FEV1/FVC normal, DLCO↓: Restrictive pattern with severe impairment of gas diffusion
  • [HRCT/Chest X-ray] Honeycombing, traction bronchiectasis, subpleural reticular opacities: Fibrotic remodeling with cystic spaces and bronchial distortion
  • [Lung biopsy] Usual interstitial pneumonia pattern with fibroblastic foci: Heterogeneous fibrosis with active fibroblast proliferation
• Management
  • Antifibrotic agents (pirfenidone, nintedanib): Inhibit fibroblast proliferation and collagen synthesis to slow disease progression
  • Oxygen therapy: Correct hypoxemia and reduce pulmonary hypertension
  • Pulmonary rehabilitation: Improve exercise capacity and quality of life through conditioning
  • Lung transplantation: Definitive treatment for end-stage disease in suitable candidates

Infectious Disease / 感染性疾患

Bacterial Pneumonia / 細菌性肺炎

• Overview
  • Acute infection of lung parenchyma caused by bacterial pathogens (Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa), leading to inflammation and consolidation of alveoli
  • Common in elderly, immunocompromised patients, and those with chronic diseases; can be community-acquired or hospital-acquired
  • Usually responds well to appropriate antibiotic therapy, but can progress to respiratory failure or sepsis if untreated
• Presentation
  • Productive cough with purulent sputum, dyspnea: Inflammatory exudate in alveoli impairs gas exchange and triggers cough reflex
  • Fever, chills, malaise: Systemic inflammatory response to bacterial infection
  • Pleuritic chest pain: Irritation of visceral and parietal pleura due to adjacent lung inflammation
  • Tachypnea, tachycardia: Compensatory response to hypoxemia and systemic infection
• Examination
  • [Blood] WBC↑, CRP↑, procalcitonin↑: Markers of bacterial infection and systemic inflammation
  • [ABG] Hypoxemia, respiratory alkalosis: Impaired gas exchange and compensatory hyperventilation
  • [Chest X-ray] Consolidation, air bronchograms: Inflammatory exudate fills alveolar spaces while bronchi remain air-filled
  • [CT] Ground-glass opacities, consolidation: More sensitive detection of inflammatory changes in lung parenchyma
  • [Sputum culture] Bacterial growth, gram staining: Identify causative organism and guide antibiotic selection
• Management
  • [Community-acquired] Amoxicillin, ceftriaxone, levofloxacin: First-line antibiotics for outpatient and hospitalized patients
  • [Hospital-acquired] Piperacillin-tazobactam, meropenem, vancomycin: Broad-spectrum coverage for resistant organisms including MRSA and Pseudomonas
  • [Targeted therapy] Penicillin (S. pneumoniae), cloxacillin (MSSA), vancomycin (MRSA), ceftazidime (Pseudomonas): Organism-specific treatment based on culture results
  • [Supportive care] Oxygen therapy, IV fluids, bronchodilators: Maintain oxygenation and hydration, improve airway clearance
  • [Severe cases] Mechanical ventilation, vasopressors: Support respiratory and circulatory function in respiratory failure or septic shock

Pulmonary Tuberculosis / 肺結核

• Overview
  • Infection of lungs by Mycobacterium tuberculosis, can be primary infection or reactivation of latent infection
  • More common in immunocompromised patients, developing countries, and elderly
  • Progressive course with potential for cavitation, fibrosis, and dissemination if untreated
• Presentation
  • Persistent cough >3 weeks, hemoptysis: Chronic inflammation and destruction of lung tissue
  • Fever, night sweats, weight loss: Chronic infection and inflammatory cytokine release
  • Chest pain, dyspnea: Pleural involvement and reduced lung capacity
• Examination
  • [Blood] ESR↑, CRP↑, anemia: Chronic inflammation and infection
  • [Sputum] Acid-fast bacilli, culture positive, PCR positive: Detection of Mycobacterium tuberculosis
  • [Chest X-ray] Upper lobe infiltrates, cavitation, lymphadenopathy: Characteristic pattern of TB infection and tissue destruction
  • [CT] Tree-in-bud pattern, cavitation, bronchiectasis: Better visualization of bronchogenic spread and lung damage
  • [TST/IGRA] Positive: Cell-mediated immune response to TB antigens
• Management
  • [Initial phase] RIPE therapy (Rifampin, Isoniazid, Pyrazinamide, Ethambutol) for 2 months: Kill actively dividing mycobacteria and prevent resistance
  • [Continuation phase] RI therapy (Rifampin, Isoniazid) for 4 months: Eliminate dormant mycobacteria
  • Directly Observed Therapy (DOT): Ensure medication compliance and prevent drug resistance
  • Respiratory isolation initially: Prevent airborne transmission until sputum conversion
  • Contact tracing and screening: Identify and treat exposed individuals

COVID-19 / 新型コロナウイルス感染症

• Overview
  • Respiratory infection caused by SARS-CoV-2 virus, highly contagious through respiratory droplets and aerosols
  • Global pandemic since 2019, affects all age groups with higher morbidity and mortality in elderly and immunocompromised individuals
  • Course ranges from asymptomatic infection to severe pneumonia, ARDS, and multi-organ failure
• Presentation
  • Fever, fatigue, myalgia, headache: Systemic inflammatory response to viral infection
  • Dry cough, dyspnea, chest pain: Viral pneumonia and lung inflammation
  • Loss of taste (ageusia), loss of smell (anosmia): Viral damage to olfactory neurons and taste receptors
  • Diarrhea, nausea, vomiting: Viral infection of GI tract through ACE2 receptors
  • [Severe cases] Respiratory distress, hypoxemia: Cytokine storm leading to ARDS and lung injury
• Examination
  • [PCR/Antigen test] Positive SARS-CoV-2: Detection of viral RNA or antigens
  • [Blood] Lymphopenia, CRP↑, D-dimer↑, ferritin↑: Immune system activation and inflammatory response
  • [Chest X-ray/CT] Ground-glass opacities, bilateral infiltrates: Viral pneumonia and inflammatory lung injury
  • [Pulse oximetry] Decreased oxygen saturation: Impaired gas exchange due to pneumonia
• Management
  • [Mild cases] Rest, hydration, symptom management: Allow immune system to clear infection
  • [Antiviral therapy] Paxlovid (nirmatrelvir/ritonavir), remdesivir: Inhibit viral replication
  • [Severe cases] Dexamethasone, tocilizumab: Reduce inflammatory response and cytokine storm
  • [Respiratory support] Oxygen therapy, mechanical ventilation, ECMO: Support gas exchange in severe cases
  • [Prevention] Vaccination (mRNA, viral vector vaccines), masking, social distancing: Prevent infection and reduce transmission

Immune Disease / 免疫性疾患

Sarcoidosis / サルコイドーシス

• Overview
  • Multi-system inflammatory disease characterized by non-caseating granulomas in affected organs
  • More common in young adults (20-40 years), higher prevalence in African Americans and Northern Europeans
  • Course varies from acute self-limiting disease to chronic progressive condition with potential for organ fibrosis
• Presentation
  • Asymptomatic (30-50% of cases): Incidental finding on chest imaging
  • Dry cough, dyspnea on exertion, chest tightness: Pulmonary granulomatous inflammation and fibrosis
  • Fatigue, weight loss, low-grade fever: Systemic inflammatory response
  • Erythema nodosum, lupus pernio: Granulomatous inflammation of skin and subcutaneous tissue
  • Blurred vision, eye pain, photophobia: Granulomatous uveitis
  • Palpitations, syncope: Cardiac granulomas causing arrhythmias or conduction blocks
  • Facial weakness, hearing loss: Granulomatous involvement of cranial nerves
• Examination
  • [Blood] ACE↑, hypercalcemia, hypercalciuria: Activated macrophages produce ACE and convert vitamin D to active form
  • [Chest X-ray/CT] Bilateral hilar lymphadenopathy, pulmonary infiltrates: Granulomatous inflammation of mediastinal lymph nodes and lung parenchyma
  • [PFT] Restrictive pattern, reduced DLCO: Pulmonary fibrosis and impaired gas exchange
  • [Tissue biopsy] Non-caseating granulomas: Characteristic histological finding with epithelioid cells and giant cells
  • [Ophthalmologic exam] Anterior/posterior uveitis: Granulomatous inflammation of uveal tract
  • [ECG] AV blocks, ventricular arrhythmias: Cardiac sarcoidosis affecting conduction system
• Management
  • Observation: For asymptomatic patients with stable disease
  • Corticosteroids (prednisolone): Suppress granulomatous inflammation and prevent organ damage
  • Immunosuppressants (methotrexate, azathioprine): Steroid-sparing agents for chronic disease or steroid intolerance
  • Anti-TNF agents (infliximab, adalimumab): For refractory cases by blocking key inflammatory cytokine

Circulatory Disease / 循環性疾患

Pulmonary Embolism / 肺塞栓症

• Overview
  • Blockage of pulmonary arteries by blood clots (usually from deep vein thrombosis), leading to impaired gas exchange
  • Risk factors include immobilization, surgery, cancer, pregnancy, contraceptives, inherited thrombophilia
  • Course ranges from asymptomatic small emboli to massive PE with hemodynamic collapse and death
• Presentation
  • Asymptomatic: Small peripheral emboli may not cause symptoms
  • Dyspnea, chest pain (pleuritic), cough, hemoptysis: Lung tissue ischemia and infarction leading to impaired gas exchange and pleural irritation
  • Tachycardia, tachypnea: Compensatory response to hypoxemia and increased physiological dead space
  • Hypotension, syncope, shock: Massive PE causing acute right heart failure and reduced cardiac output
• Examination
  • [Blood] D-dimer↑: Fibrin degradation products from clot formation and breakdown
  • [ABG] Hypoxemia, hypocapnia, increased A-a gradient: Ventilation-perfusion mismatch and compensatory hyperventilation
  • [ECG] S1Q3T3 pattern, right axis deviation, T-wave inversions V1-V4: Acute right heart strain
  • [Chest X-ray] Often normal, wedge-shaped opacity, elevated hemidiaphragm: Pulmonary infarction (Hampton’s hump, Westermark sign)
  • [CT pulmonary angiogram] Filling defects in pulmonary arteries: Direct visualization of embolic clots
  • [V/Q scan] Perfusion defects with normal ventilation: Mismatched ventilation-perfusion
  • [Echocardiogram] Right heart dilatation, McConnell’s sign, tricuspid regurgitation: Right heart dysfunction from increased pulmonary vascular resistance
• Management
  • [Anticoagulation] Heparin (IV/SC), warfarin, DOACs: Prevent further clot formation and extension of existing thrombi
  • [Massive PE] Systemic thrombolysis (tPA), surgical embolectomy, catheter-directed thrombolysis: Rapidly dissolve or remove clot to restore pulmonary circulation
  • [IVC filter]: When anticoagulation contraindicated or recurrent PE despite adequate anticoagulation
  • [Supportive care] Oxygen therapy, IV fluids, vasopressors: Maintain oxygenation and hemodynamic stability

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

• Overview
  • Elevated pulmonary artery pressure due to increased pulmonary vascular resistance from vasoconstriction, remodeling, and thrombosis of small pulmonary arteries
  • Rare disease affecting 15-50 per million population, more common in 30s-40s women
  • Progressive disease leading to right heart failure and death if untreated
• Presentation
  • Dyspnea on exertion, fatigue, exercise intolerance: Reduced cardiac output and impaired pulmonary gas exchange due to increased pulmonary vascular resistance
  • Chest pain, syncope: Right ventricular ischemia and reduced systemic perfusion due to right heart strain
  • Peripheral edema, ascites, jugular venous distension: Right heart failure with elevated right-sided filling pressures
• Examination
  • [Blood] BNP/NT-proBNP↑, D-dimer↑: Right heart failure and potential microthrombi formation
  • [ECG] Right axis deviation, right ventricular hypertrophy, P pulmonale: Right heart strain and enlargement
  • [Echocardiography] RVSP↑ (>35 mmHg), right heart enlargement, tricuspid regurgitation: Elevated pulmonary pressures and right heart dysfunction
  • [Chest X-ray] Enlarged central pulmonary arteries, peripheral pruning: Increased pulmonary vascular pressures
  • [Right heart catheterization] mPAP ≥20 mmHg, PCWP ≤15 mmHg, PVR >3 Wood units: Gold standard showing elevated pulmonary pressures with normal left heart pressures
• Management
  • Oxygen therapy (if hypoxic), diuretics, anticoagulation: Improve oxygenation, reduce fluid overload, prevent thrombosis
  • Endothelin receptor antagonists (bosentan, ambrisentan): Block vasoconstriction and vascular remodeling by inhibiting endothelin-1 pathway
  • Phosphodiesterase-5 inhibitors (sildenafil, tadalafil): Enhance vasodilation by increasing cGMP levels in pulmonary vessels
  • Prostacyclin analogues (epoprostenol, treprostinil): Provide vasodilation and antiproliferative effects through cAMP pathway
  • Lung transplantation: Definitive treatment for end-stage disease when medical therapy fails

Functional Disease / 機能性疾患

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

• Overview
  • Repeated collapse of upper airway during sleep due to muscle relaxation and anatomical narrowing, leading to intermittent hypoxemia and sleep fragmentation
  • More common in middle-aged men, strongly associated with obesity
  • Progressive condition that can lead to cardiovascular and metabolic complications if untreated
• Presentation
  • Loud snoring, witnessed apneas: Upper airway obstruction and intermittent airflow cessation
  • Excessive daytime sleepiness, fatigue: Sleep fragmentation and repeated arousals from hypoxemia
  • Morning headaches: Nocturnal hypoxemia and hypercapnia leading to cerebral vasodilation
• Examination
  • [Polysomnography] AHI ≥5/hour, oxygen desaturations, sleep fragmentation: Repeated airway obstructions during sleep
  • [Physical exam] Enlarged tonsils, macroglossia, retrognathia, high BMI: Anatomical factors contributing to upper airway narrowing
• Management
  • Continuous positive airway pressure (CPAP): Pneumatic splinting to maintain upper airway patency
  • Weight loss, sleep position therapy: Reduce anatomical obstruction and improve airway stability
  • Oral appliances (mandibular advancement devices): Advance mandible and increase upper airway space
  • Upper airway surgery (UPPP, genioglossus advancement): Remove or reposition anatomical obstructions

Lung Tumor / 肺腫瘍

Lung Cancer / 肺癌

• Overview
  • Malignant transformation of lung epithelial cells, primarily due to smoking (85-90%), environmental carcinogens (asbestos, radon), and genetic factors
  • Non-small cell lung cancer (NSCLC) 85%: Adenocarcinoma (most common, peripheral), squamous cell carcinoma (central, cavitation), large cell carcinoma (poorly differentiated)
  • Small cell lung cancer (SCLC) 15%: Highly aggressive, central location, early metastasis, neuroendocrine features
  • Leading cause of cancer-related death worldwide, predominantly affects smokers and middle-aged to elderly individuals
  • Often diagnosed at advanced stages with poor prognosis due to late symptom onset
• Presentation
  • Persistent cough, dyspnea, chest pain, hemoptysis: Tumor growth obstructs airways and invades surrounding tissue
  • Weight loss, fatigue, anorexia: Cancer cachexia due to increased metabolic demands and inflammatory cytokines
  • Hoarseness: Recurrent laryngeal nerve compression by mediastinal lymph nodes
  • Facial swelling, neck vein distension: Superior vena cava syndrome due to tumor compression
  • Bone pain, neurological symptoms: Metastases to bone, brain, or liver
  • Clubbing, hyponatremia, hypercalcemia: Paraneoplastic syndromes from ectopic hormone production
• Examination
  • [Blood] CEA↑, CYFRA21-1↑ (NSCLC), NSE↑ (SCLC): Tumor markers released by cancer cells
  • [Bronchoscopy] Endobronchial lesion: Direct visualization of tumor
  • [Chest X-ray] Pulmonary nodule, mass, pleural effusion: Direct visualization of tumor or complications
  • [CT chest] Spiculated mass, lymphadenopathy, pleural thickening: Detailed tumor characteristics and staging
  • [PET scan] Increased FDG uptake: High metabolic activity of malignant cells
  • [Biopsy] Tissue sampling (bronchoscopy, CT-guided, surgical): Histological diagnosis and molecular profiling
• Management
  • [NSCLC Stage I-II] Surgical resection (segmentectomy, lobectomy): Complete removal of tumor-containing lung tissue
  • [NSCLC Stage III] Concurrent chemoradiotherapy: Combined treatment to control local disease and micrometastases
  • [NSCLC Stage IV] Systemic chemotherapy (platinum-based doublets): Cytotoxic agents target rapidly dividing cancer cells
  • [NSCLC with mutations] Targeted therapy (EGFR, ALK, ROS1 inhibitors): Block specific molecular pathways driving tumor growth
  • [NSCLC high PD-L1] Immunotherapy (checkpoint inhibitors): Enhance immune system recognition and destruction of cancer cells
  • [SCLC Limited stage] Concurrent chemoradiotherapy: Chemotherapy with thoracic radiation for localized disease
  • [SCLC Extensive stage] Systemic chemotherapy + immunotherapy: Platinum-based chemotherapy with atezolizumab
  • [Palliative care] Symptom management, radiation for bone metastases: Improve quality of life and manage complications

Pleural Disease / 胸膜疾患

Pleural Effusion / 胸水

• Overview
  • Accumulation of fluid in pleural space, classified as transudate (low protein) or exudate (high protein) based on underlying pathophysiology
  • Causes include heart failure, infection, malignancy
  • Course varies from acute to chronic depending on etiology
• Presentation
  • Asymptomatic: Small effusions may not cause symptoms
  • Dyspnea, reduced exercise tolerance: Compression of lung tissue and impaired gas exchange
  • Pleuritic chest pain, dry cough: Irritation and inflammation of pleural surfaces
• Examination
  • [Physical] Decreased breath sounds, dullness to percussion, decreased tactile fremitus: Fluid accumulation dampens sound transmission
  • [Chest X-ray] Blunting of costophrenic angles, meniscus sign: Fluid layering in dependent portions of pleural space
  • [CT] Fluid collection, underlying pathology: Better visualization of fluid distribution and causative lesions
  • [Ultrasound] Anechoic fluid collection: Real-time visualization, guides thoracentesis
  • [Pleural fluid analysis] Light’s criteria (protein, LDH), cell count, culture, cytology: Differentiate transudative vs exudative causes
• Management
  • Thoracentesis: Diagnostic sampling and symptomatic relief by fluid removal
  • Chest tube drainage: For large effusions or empyema to achieve complete drainage
  • Treatment of underlying cause: Heart failure management, antibiotics for infection, chemotherapy for malignancy

Pneumothorax / 気胸

• Overview
  • Air accumulation in pleural space, causing lung collapse due to rupture of visceral pleura or chest wall injury
  • Primary spontaneous: young, tall, thin males; Secondary spontaneous: patients with underlying lung disease (COPD, asthma); Traumatic: following chest trauma or medical procedures
  • May progress to tension pneumothorax with hemodynamic compromise if untreated
• Presentation
  • Sudden sharp chest pain: Pleural irritation and stretching of parietal pleura
  • Shortness of breath: Reduced lung capacity and impaired gas exchange
  • Tracheal deviation, jugular vein distension, hypotension: Tension pneumothorax compresses mediastinum and impairs venous return
• Examination
  • [Physical] Decreased breath sounds, hyperresonance to percussion, reduced chest expansion: Air in pleural space prevents normal lung expansion and sound transmission
  • [Chest X-ray] Pleural line, lung collapse, mediastinal shift: Air-fluid interface visible, lung retraction from chest wall
  • [CT scan] Pleural air collection, lung atelectasis: More sensitive detection of small pneumothorax
  • [ABG] Hypoxemia, respiratory alkalosis: Impaired gas exchange and compensatory hyperventilation
• Management
  • [Small pneumothorax <20%] Observation, oxygen therapy: Small air collections may reabsorb spontaneously
  • [Large pneumothorax >20%] Needle decompression (emergency), chest tube insertion: Remove trapped air and allow lung re-expansion
  • [Tension pneumothorax] Immediate needle decompression: Emergency relief of pressure to prevent cardiovascular collapse
  • [Recurrent pneumothorax] VATS, pleurodesis: Surgical repair of blebs and prevention of recurrence by pleural adhesion

Mediastinal Disease / 縦隔疾患

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

Gastroenterology / 消化器科

Endocrinology / 内分泌科

Glucose Metabolism Disorder / 糖代謝異常

Type 1 Diabetes Mellitus / 1型糖尿病

• Overview
  • Autoimmune destruction of pancreatic beta cells leading to absolute insulin deficiency
  • Peak incidence in childhood and adolescence, genetic predisposition (HLA-DR3, HLA-DR4)
  • Rapid onset over weeks to months, requires lifelong insulin therapy
• Presentation
  • Polyuria, polydipsia: Hyperglycemia causes osmotic diuresis and dehydration
  • Weight loss despite increased appetite: Inability to utilize glucose leads to protein and fat catabolism
  • Fatigue, weakness: Cellular energy deficit due to glucose unavailability
  • Blurred vision: Osmotic changes in lens due to hyperglycemia
  • [DKA] Nausea, vomiting, abdominal pain: Ketone production from fat metabolism due to insulin deficiency
  • [DKA] Kussmaul breathing, fruity breath odor: Respiratory compensation for metabolic acidosis and acetone elimination
• Examination
  • [Blood] Glucose ≥126 mg/dL (fasting) or ≥200 mg/dL (random): Insufficient insulin production
  • [Blood] HbA1c ≥6.5%: Reflects average glucose levels over 2-3 months
  • [Blood] C-peptide low/absent: Minimal endogenous insulin production
  • [Blood] Autoantibodies positive (anti-GAD, anti-IA2, anti-ZnT8): Autoimmune destruction of beta cells
  • [Urine] Glucose positive, ketones positive: Overflow of glucose and ketone production
  • [Blood] pH <7.3, bicarbonate <15 mEq/L (in DKA): Metabolic acidosis from ketoacidosis
• Management
  • [Rapid-acting insulin] Lispro, aspart, glulisine: Mimics physiological meal-time insulin response, peaks in 1-2 hours
  • [Short-acting insulin] Regular insulin: Covers meals, peaks in 2-4 hours
  • [Intermediate-acting insulin] NPH: Provides basal coverage for 12-18 hours
  • [Long-acting insulin] Glargine, detemir, degludec: Provides 24-hour basal insulin with minimal peak
  • [Continuous glucose monitoring]: Real-time glucose tracking to optimize insulin dosing
  • [Insulin pump therapy]: Continuous subcutaneous insulin infusion for precise dosing

Type 2 Diabetes Mellitus / 2型糖尿病

• Overview
  • Insulin resistance combined with progressive beta cell dysfunction leading to relative insulin deficiency
  • Typically adult onset, strongly associated with obesity, metabolic syndrome, and family history
  • Gradual onset with progressive deterioration of glycemic control over years
• Presentation
  • Often asymptomatic in early stages: Gradual onset with slowly rising glucose levels
  • Polyuria, polydipsia: Hyperglycemia causes osmotic diuresis and dehydration
  • Fatigue, weakness: Cellular glucose uptake impairment due to insulin resistance
  • Recurrent infections (UTIs, skin infections): Hyperglycemia impairs immune function
  • Slow wound healing: Impaired circulation and immune response
  • Acanthosis nigricans: Dark skin patches in neck/axilla due to insulin resistance
  • Numbness/tingling (neuropathy), blurred vision (retinopathy), proteinuria (nephropathy): Chronic hyperglycemia damages nerves, retinal vessels, and kidneys
• Examination
  • [Blood] Glucose ≥126 mg/dL (fasting) or ≥200 mg/dL (random): Insulin resistance and beta cell dysfunction
  • [Blood] HbA1c ≥6.5%: Reflects chronic hyperglycemia
  • [Blood] C-peptide normal/elevated: Endogenous insulin production maintained initially
  • [Blood] Autoantibodies negative: Non-autoimmune pathogenesis
  • [Urine] Glucose positive, protein positive (if nephropathy): Overflow and kidney damage
  • [Fundoscopy] Diabetic retinopathy: Microangiopathy from chronic hyperglycemia
• Management
  • [Lifestyle modification] Diet, exercise, weight loss: Improves insulin sensitivity and glucose uptake by muscles
  • [Metformin] First-line therapy: Decreases hepatic glucose production, improves peripheral insulin sensitivity
  • [Sulfonylureas] Glyburide, glipizide, glimepiride: Stimulate insulin release by closing ATP-sensitive K+ channels in beta cells
  • [DPP-4 inhibitors] Sitagliptin, saxagliptin: Inhibit dipeptidyl peptidase-4, prolonging incretin hormone action (GLP-1, GIP)
  • [GLP-1 agonists] Exenatide, liraglutide, semaglutide: Mimic incretin hormones, stimulate insulin release, suppress glucagon, slow gastric emptying
  • [SGLT-2 inhibitors] Canagliflozin, dapagliflozin: Block sodium-glucose cotransporter-2 in kidneys, causing glucose excretion
  • [Thiazolidinediones] Pioglitazone: Activate PPAR-γ receptors, improve insulin sensitivity in muscle and adipose tissue
  • [Alpha-glucosidase inhibitors] Acarbose: Inhibit intestinal alpha-glucosidases, delay carbohydrate absorption
  • [Insulin therapy]: Added when oral agents insufficient, same mechanisms as T1DM treatment

Diabetic Ketoacidosis / 糖尿病性ケトアシドーシス

• Overview
  • Life-threatening complication of diabetes mellitus due to severe insulin deficiency, leading to hyperglycemia, ketosis, and metabolic acidosis
  • More common in type 1 diabetes, but can occur in type 2 diabetes under stress
  • Often triggered by infection, illness, missed insulin doses; life-threatening condition requiring immediate treatment
• Presentation
  • Polyuria, polydipsia, dehydration: Osmotic diuresis due to hyperglycemia leads to fluid and electrolyte loss
  • Nausea, vomiting, abdominal pain: Ketone bodies irritate gastric mucosa and delay gastric emptying
  • Fruity breath odor: Acetone elimination through lungs
  • Kussmaul breathing (deep, rapid respirations): Respiratory compensation for metabolic acidosis
  • Altered mental status, confusion, coma: Severe dehydration, acidosis, and osmolar changes affect brain function
• Examination
  • [Blood] Glucose >250mg/dL: Hyperglycemia due to insulin deficiency and increased gluconeogenesis
  • [Blood/Urine] Ketones positive (β-hydroxybutyrate, acetoacetate): Increased lipolysis and ketogenesis due to insulin deficiency
  • [Blood/ABG] pH <7.30, HCO₃⁻ <15mEq/L, anion gap >12mEq/L: Metabolic acidosis from ketoacid accumulation
• Management
  • IV fluid resuscitation: Correct dehydration and restore circulation
  • Continuous IV insulin infusion: Suppress ketogenesis, reduce glucose production, increase glucose uptake
  • Potassium replacement: Correct hypokalemia that develops during treatment as potassium shifts intracellularly
  • Bicarbonate (if pH <7.0): Correct severe acidosis that may impair cardiac function
  • Identify and treat precipitating cause: Address underlying infection, illness, or medication non-compliance

Lipid Metabolism Disorder / 脂質代謝異常

Dyslipidemia / 脂質異常症

• Overview
  • Abnormal levels of lipids in blood (↑LDL-C, ↑TG, ↓HDL-C), leading to atherosclerosis and cardiovascular disease
  • Very common condition, prevalence increases with age, sedentary lifestyle, and Western diet
  • Often asymptomatic for years until cardiovascular complications develop
• Presentation
  • Asymptomatic in early stages: No symptoms until complications occur
  • Xanthomas, xanthelasma, corneal arcus: Lipid deposits in skin, eyelids, and cornea due to high cholesterol levels
  • Chest pain, dyspnea on exertion: Coronary atherosclerosis leading to myocardial ischemia
  • Acute pancreatitis (severe hypertriglyceridemia): TG >1000 mg/dL causes pancreatic inflammation
• Examination
  • [Blood] LDL-C ≥140 mg/dL, HDL-C <40 mg/dL, TG ≥150 mg/dL: Direct measurement of abnormal lipid levels
  • [Blood] ApoB↑, ApoA1↓, Lp(a)↑: Additional lipid markers indicating cardiovascular risk
  • [Ultrasound, CT] Carotid artery stenosis, coronary artery disease: Imaging evidence of atherosclerotic disease
• Management
  • Lifestyle modification (diet, exercise, weight loss): Reduce lipid synthesis and increase lipid metabolism
  • Statins (atorvastatin, simvastatin): Inhibit HMG-CoA reductase, reduce cholesterol synthesis
  • Ezetimibe: Block cholesterol absorption in small intestine
  • Fibrates (fenofibrate): Activate PPAR-α, reduce triglycerides and increase HDL-C
  • PCSK9 inhibitors (evolocumab, alirocumab): Increase LDL receptor recycling, dramatically lower LDL-C
  • Bile acid sequestrants (cholestyramine): Bind bile acids, increase cholesterol conversion to bile acids

Obesity / 肥満症

• Overview
  • Chronic condition characterized by excessive fat accumulation due to energy intake consistently exceeding energy expenditure
  • Highly prevalent worldwide, affecting all age groups with increasing incidence in developed countries
  • Progressive condition that leads to multiple comorbidities if left untreated
• Presentation
  • Often asymptomatic in early stages
  • Shortness of breath, reduced exercise tolerance: Increased oxygen demand and mechanical burden on respiratory system
  • Joint pain, back pain, mobility difficulties: Increased mechanical stress on weight-bearing joints and spine
  • Sleep disturbances, snoring: Upper airway obstruction due to excess neck fat and reduced muscle tone
• Examination
  • [Anthropometric] BMI ≥30 kg/m², increased waist circumference: Excess body fat and central adiposity
  • [Blood] Fasting glucose↑, HbA1c↑, insulin resistance: Metabolic dysfunction and impaired glucose metabolism
  • [Blood] Total cholesterol↑, LDL↑, HDL↓, triglycerides↑: Dyslipidemia due to altered fat metabolism
  • [Blood] ALT↑, AST↑: Non-alcoholic fatty liver disease from excess fat deposition in liver
  • [Blood pressure] Hypertension: Increased peripheral resistance and cardiac output
• Management
  • Caloric restriction diet, increased physical activity: Create energy deficit to promote fat loss and improve metabolic health
  • Behavioral therapy, counseling: Address psychological factors and establish sustainable lifestyle changes
  • [Pharmacological] Orlistat: Inhibits pancreatic lipase to reduce fat absorption
  • [Pharmacological] GLP-1 receptor agonists (semaglutide, liraglutide): Delay gastric emptying and increase satiety
  • [Surgical] Bariatric surgery (gastric bypass, sleeve gastrectomy): Restrict stomach capacity and/or alter nutrient absorption for severe obesity

Miscellaneous Metabolism Disorder / その他の代謝異常

Hyperuricemia / 高尿酸血症

• Overview
  • Elevated serum uric acid levels due to overproduction or underexcretion of uric acid
  • Common in middle-aged men and postmenopausal women, associated with metabolic syndrome, obesity, and high purine diet
  • Often asymptomatic but may progress to gout attacks, kidney stones, or chronic kidney disease
• Presentation
  • Asymptomatic hyperuricemia: Most cases have no symptoms
  • Acute joint pain, swelling, redness (typically first metatarsophalangeal joint): Uric acid crystals deposit in synovial joints triggering inflammatory response
  • Flank pain, hematuria: Uric acid precipitation forms kidney stones
  • Painless subcutaneous nodules (tophi): Chronic uric acid crystal deposits in soft tissues, ears, joints
• Examination
  • [Blood] Serum uric acid >7.0 mg/dL (men), >6.0 mg/dL (women): Elevated uric acid levels
  • [Blood] Creatinine↑, BUN↑: Kidney dysfunction from chronic hyperuricemia
  • [Synovial fluid] Uric acid crystals (needle-shaped, negatively birefringent): Crystal arthropathy confirmation during acute gout
  • [X-ray] Joint erosions, punched-out lesions: Chronic gouty arthropathy
  • [Ultrasound] Hyperechoic deposits on cartilage, tophi: Uric acid crystal deposits
• Management
  • Lifestyle modifications (low-purine diet, weight loss, limit alcohol): Reduce uric acid production and improve excretion
  • [Acute gout] NSAIDs, colchicine, corticosteroids: Anti-inflammatory effects to reduce joint inflammation
  • [Chronic] Allopurinol, febuxostat: Xanthine oxidase inhibitors reduce uric acid production
  • [Chronic] Probenecid: Increases uric acid excretion by blocking renal tubular reabsorption
  • [Severe] Pegloticase: Uricase enzyme converts uric acid to allantoin for excretion

Osteoporosis / 骨粗鬆症

• Overview
  • Bone resorption exceeds bone formation, leading to decreased bone mineral density and microarchitectural deterioration of bone tissue
  • Primarily affects postmenopausal women (estrogen deficiency) and elderly men over 70, also secondary to medications (corticosteroids) or diseases
  • Progressive bone loss with increased fracture risk, especially in spine, hip, and wrist
• Presentation
  • Asymptomatic in early stages: Bone loss occurs gradually without symptoms
  • Back pain, loss of height, kyphosis: Vertebral compression fractures due to weakened vertebral bodies
  • Fragility fractures from minor trauma: Hip, wrist, vertebral fractures due to decreased bone strength and increased bone fragility
• Examination
  • [DEXA scan] T-score ≤ -2.5: Bone mineral density measurement showing significant bone loss compared to healthy young adults
  • [X-ray] Vertebral compression fractures, decreased bone density, cortical thinning: Direct visualization of fractures and bone changes
  • [Blood] Normal calcium, phosphate, ALP (elevated if recent fracture): Rule out other metabolic bone diseases
• Management
  • Calcium (1000-1200mg/day) and Vitamin D (800-1000 IU/day) supplementation: Provide essential building blocks for bone mineralization
  • Bisphosphonates (alendronate, risedronate, zoledronic acid): Inhibit osteoclast activity to reduce bone resorption
  • Denosumab: RANKL inhibitor that prevents osteoclast formation and activation
  • Teriparatide or abaloparatide: PTH analogs that stimulate osteoblast activity for severe cases
  • Calcium and vitamin D supplementation: Provide essential nutrients for bone mineralization
  • Weight-bearing exercise, resistance training: Mechanical stress stimulates bone formation and maintains bone density

Vitamin D Deficiency / ビタミンD欠乏症

• Overview
  • Insufficient vitamin D levels leading to decreased calcium absorption and bone mineralization
  • Common worldwide, especially in high-latitude regions, elderly, individuals with limited sun exposure, dark skin, malabsorption disorders
  • Asymptomatic initially, progresses to rickets in children and osteomalacia in adults if untreated
• Presentation
  • Bone pain, muscle weakness, muscle cramps: Poor calcium absorption and secondary hyperparathyroidism leading to bone demineralization and muscle dysfunction
  • Increased fracture risk, bone deformities: Weakened bone structure due to poor mineralization in severe cases
  • Fatigue, depression, mood changes: Vitamin D receptors in brain and nervous system affecting neurotransmitter synthesis
  • [Children] Delayed tooth eruption, growth retardation, bone deformities (rickets): Impaired bone mineralization during growth and development
• Examination
  • [Blood] 25(OH)D↓, PTH↑: Low vitamin D storage form, compensatory parathyroid hormone elevation
  • [Blood] ALP↑, calcium↓/normal, phosphate↓: Increased bone turnover, impaired calcium absorption, phosphate wasting
  • [X-ray] Osteopenia, pseudofractures (Looser zones), bone deformities: Bone demineralization and structural changes
  • [DEXA scan] Low bone mineral density: Reduced bone mass due to poor mineralization
• Management
  • Vitamin D3 (cholecalciferol) supplementation: Replenish vitamin D stores and restore normal calcium absorption
  • Calcium supplementation: Ensure adequate calcium intake for bone mineralization
  • Sunlight exposure, dietary sources (fatty fish, fortified foods): Natural vitamin D synthesis and dietary intake

Pituitary Disease / 下垂体疾患

Hyperprolactinemia / 高プロラクチン血症

• Overview
  • Elevated serum prolactin levels due to pituitary adenoma, medications, or other causes
  • More common in women of reproductive age, can occur at any age
  • May cause reproductive dysfunction and mass effect symptoms if large pituitary tumor present
• Presentation
  • [Women] Amenorrhea, oligomenorrhea, infertility: Prolactin suppresses GnRH release, leading to hypogonadotropic hypogonadism
  • [Women] Galactorrhea: Direct stimulation of mammary glands by prolactin
  • [Men] Decreased libido, erectile dysfunction, infertility: Prolactin suppresses LH and FSH, reducing testosterone production
  • [Men] Gynecomastia: Hormonal imbalance and direct prolactin effects on breast tissue
  • [Both] Headaches, visual field defects: Mass effect from large pituitary adenomas (macroadenomas >1cm) compressing surrounding structures
  • [Both] Osteoporosis: Chronic hypogonadism leads to decreased bone density
• Examination
  • [Blood] Prolactin↑, TSH, creatinine: Confirm hyperprolactinemia and exclude secondary causes
  • [Blood] LH↓, FSH↓, testosterone↓ (men), estradiol↓ (women): Hypogonadotropic hypogonadism from prolactin excess
  • [MRI pituitary] Microadenoma (<10mm) or macroadenoma (≥10mm): Identify pituitary tumor as cause
  • [Visual field testing] Bitemporal hemianopia: Assess for optic chiasm compression in macroadenomas
  • [DEXA scan] Decreased bone mineral density: Screen for osteoporosis from chronic hypogonadism
• Management
  • Dopamine agonists (cabergoline, bromocriptine): Inhibit prolactin secretion by stimulating dopamine D2 receptors on lactotrophs
  • Transsphenoidal surgery: Remove pituitary adenoma in cases resistant to medical therapy or with significant mass effect
  • [Hypogonadism] Hormone replacement therapy: Restore sex hormones if dopamine agonists contraindicated
  • [Drug-induced] Discontinue or substitute offending medications: Remove causative agents (antipsychotics, antidepressants, antiemetics)

Acromegaly / 先端巨大症

• Overview
  • Excess growth hormone (GH) secretion after epiphyseal closure, usually from pituitary adenoma
  • Rare condition, typically affects middle-aged adults (40-60 years)
  • Slowly progressive course over years to decades
• Presentation
  • Enlarged hands, feet, jaw, facial features (coarse facies): Excess GH stimulates bone and soft tissue growth
  • Macroglossia, deep voice, sleep apnea: Soft tissue overgrowth in upper airway and tongue
  • Diabetes mellitus, hypertension: GH antagonizes insulin action and affects cardiovascular system
  • Arthralgia, carpal tunnel syndrome: Joint cartilage overgrowth and nerve compression
  • Headache, bitemporal hemianopia: Pituitary adenoma compresses optic chiasm and causes mass effect
• Examination
  • [Blood] GH↑, IGF-1↑: Direct measurement of hormone excess
  • [Oral glucose tolerance test] Failed GH suppression (<1 ng/mL): GH normally suppressed by glucose load, but remains elevated in acromegaly
  • [MRI] Pituitary adenoma (micro- or macroadenoma): Identify source of GH excess and evaluate mass effect
  • [Visual field test] Bitemporal hemianopia: Compression of optic chiasm by large pituitary tumors
• Management
  • Transsphenoidal surgery: First-line treatment to remove pituitary adenoma and normalize GH levels
  • Somatostatin analogs (octreotide, lanreotide): Suppress GH secretion by binding to somatostatin receptors on pituitary adenoma
  • GH receptor antagonist (pegvisomant): Blocks GH action at tissue level, normalizes IGF-1
  • Dopamine agonists (cabergoline): Suppress GH secretion in some somatotroph adenomas with dopamine receptors
  • Radiotherapy: For residual or recurrent disease after surgery

Thyroid Disease / 甲状腺疾患

Hyperthyroidism / 甲状腺機能亢進症

• Overview
  • Excessive production and release of thyroid hormones (T3, T4) leading to hypermetabolic state, causes including Graves’ disease, toxic multinodular goiter, or thyroiditis
  • More common in women (5:1 ratio), peak incidence 20-40 years old
  • Can range from mild subclinical to life-threatening thyroid storm
• Presentation
  • Weight loss despite increased appetite, heat intolerance: Increased metabolic rate and thermogenesis
  • Palpitations, tachycardia, atrial fibrillation: Direct cardiac stimulation by thyroid hormones
  • Anxiety, irritability, tremor, insomnia: CNS stimulation and increased adrenergic activity
  • Muscle weakness, fatigue: Protein catabolism and myopathy
  • Diarrhea, frequent bowel movements: Increased GI motility
  • Exophthalmos, diplopia (Graves’ disease): Orbital tissue inflammation and extraocular muscle involvement
• Examination
  • [Blood] TSH↓, Free T4↑, Free T3↑: Negative feedback suppression of TSH and excess thyroid hormone production
  • [Blood] TSI↑, TRAb↑ (Graves’ disease): Thyroid-stimulating immunoglobulins mimicking TSH action
  • [Thyroid scintigraphy] Increased uptake (Graves’, toxic nodular goiter) or decreased uptake (thyroiditis): Reflects thyroid activity and cause
• Management
  • Antithyroid drugs (methimazole, propylthiouracil): Block thyroid hormone synthesis by inhibiting thyroid peroxidase
  • Beta-blockers (propranolol, metoprolol): Control sympathetic symptoms and reduce T4 to T3 conversion
  • Radioiodine therapy (I-131): Destroy thyroid tissue through targeted radiation
  • Thyroidectomy: Surgical removal of thyroid gland for large goiters or malignancy concerns
  • [Thyroid storm] High-dose antithyroid drugs, iodine, corticosteroids, beta-blockers, supportive care: Emergency treatment to prevent cardiovascular collapse

Hypothyroidism / 甲状腺機能低下症

• Overview
  • Decreased production of thyroid hormones T3 and T4, most commonly due to autoimmune destruction of thyroid gland (Hashimoto’s thyroiditis)
  • More common in women, incidence increases with age, affects 1-2% of population
  • Usually chronic and progressive if untreated, but reversible with appropriate treatment
• Presentation
  • Fatigue, weakness, weight gain, cold intolerance: Decreased metabolic rate due to insufficient thyroid hormones
  • Constipation, decreased appetite: Reduced gastrointestinal motility due to metabolic slowdown
  • Depression, memory impairment, cognitive dysfunction: Decreased thyroid hormone effects on central nervous system
  • Bradycardia, hypotension: Decreased cardiac output due to low metabolic rate
  • Dry skin, hair loss, brittle nails: Decreased protein synthesis and cellular metabolism in skin and hair follicles
  • Menstrual irregularities, infertility: Altered hypothalamic-pituitary-gonadal axis due to thyroid hormone deficiency
• Examination
  • [Blood] TSH↑, T4↓, T3↓: Primary hypothyroidism with compensatory TSH elevation from pituitary
  • [Blood] Anti-TPO antibodies↑, anti-thyroglobulin antibodies↑: Autoimmune thyroiditis (Hashimoto’s disease)
  • [Physical] Goiter (in some cases), periorbital edema: Thyroid enlargement due to TSH stimulation, myxedema from mucopolysaccharide accumulation* Management
  • Levothyroxine (L-T4) replacement therapy: Synthetic T4 hormone replacement, converted to active T3 in peripheral tissues
  • Lifelong treatment and monitoring: Regular TSH monitoring every 6-12 months once stable dose achieved

Thyroid Cancer / 甲状腺癌

• Overview
  • Malignant neoplasm of thyroid gland, including papillary (80-85%), follicular (10-15%), medullary (3-5%), and anaplastic (<2%) carcinomas
  • More common in women, peak incidence 30-50 years, risk factors include radiation exposure, iodine deficiency/excess, family history
  • Generally slow-growing and good prognosis for differentiated types (papillary, follicular), poor prognosis for anaplastic type
• Presentation
  • Asymptomatic thyroid nodule: Early stage, slow-growing differentiated cancers
  • Neck mass, lymphadenopathy: Local tumor growth and regional metastasis
  • Hoarseness, voice changes: Recurrent laryngeal nerve invasion or compression
  • Dysphagia, dyspnea: Compression of esophagus or trachea by large tumor
• Examination
  • [Blood] TSH normal/low, thyroglobulin↑: Most thyroid cancers are euthyroid, thyroglobulin as tumor marker for differentiated cancers
  • [Blood] Calcitonin↑, CEA↑: Specific markers for medullary thyroid carcinoma
  • [Ultrasound] Hypoechoic nodule, microcalcifications, irregular borders, increased vascularity: Malignant features on imaging
  • [FNA biopsy] Malignant cells, specific histological patterns: Definitive diagnosis through cytological examination
  • [CT/MRI] Local invasion, lymph node metastasis: Assess tumor extent and staging
  • [Radioiodine scan] Cold nodule (non-functioning): Most thyroid cancers do not concentrate iodine
• Management
  • Total thyroidectomy or lobectomy: Remove primary tumor, extent depends on tumor size, type, and staging
  • Lymph node dissection: Remove involved cervical lymph nodes if metastases present
  • Radioiodine (I-131) therapy: Ablate remnant thyroid tissue and treat metastases in iodine-avid tumors
  • Levothyroxine hormone replacement therapy: Replace thyroid hormone and suppress TSH to prevent tumor growth
  • External beam radiation therapy: For anaplastic carcinoma or locally advanced disease not amenable to surgery
  • Targeted therapy (sorafenib, lenvatinib): For advanced, radioiodine-refractory differentiated thyroid cancer

Parathyroid Disease / 副甲状腺疾患

Hyperparathyroidism / 副甲状腺機能亢進症

• Overview
  • Excessive secretion of parathyroid hormone (PTH) leading to hypercalcemia and hypophosphatemia
  • Primary (85%): parathyroid adenoma or hyperplasia; Secondary: chronic kidney disease, vitamin D deficiency; Tertiary: autonomous PTH secretion after long-standing secondary hyperparathyroidism
  • More common in women, peak incidence 50-60 years old
• Presentation
  • Bone pain, fractures, osteoporosis: Excessive PTH stimulates osteoclast activity, leading to bone resorption and weakening
  • Polyuria, polydipsia, kidney stones: Hypercalcemia impairs renal concentrating ability and promotes calcium stone formation
  • Nausea, vomiting, constipation, peptic ulcers: Hypercalcemia affects GI smooth muscle function and increases gastric acid secretion
  • Confusion, depression, memory problems, fatigue: Hypercalcemia affects neuronal membrane excitability and neurotransmitter function
• Examination
  • [Blood] PTH↑, serum calcium↑, phosphate↓: Direct effects of excessive PTH secretion
  • [Blood] ALP↑, 25(OH)D↓/normal, 1,25(OH)₂D↑: Increased bone turnover and PTH-stimulated vitamin D activation
  • [DEXA scan] Low bone mineral density: Chronic bone resorption due to PTH excess
  • [Ultrasound, Sestamibi scan] Parathyroid adenoma or hyperplasia: Localize abnormal parathyroid glands
• Management
  • [Primary, asymptomatic] Observation, bisphosphonates: Monitor for progression; bisphosphonates reduce bone resorption
  • [Primary, symptomatic] Parathyroidectomy: Remove abnormal parathyroid glands to normalize PTH secretion
  • [Secondary] Vitamin D supplementation, phosphate binders, dietary modifications: Address underlying causes like vitamin D deficiency or chronic kidney disease
  • [Acute hypercalcemic crisis] IV saline, loop diuretics, bisphosphonates, calcitonin: Rapidly lower serum calcium levels

Adrenal Disease / 副腎疾患

Cushing Syndrome / クッシング症候群

• Overview
  • Prolonged exposure to excess cortisol due to pituitary adenoma (Cushing’s disease), adrenal tumors, ectopic ACTH syndrome, or exogenous corticosteroids
  • More common in adults aged 30-50, female predominance
  • Chronic progressive condition with gradual onset of symptoms over months to years
• Presentation
  • Central obesity, moon face, buffalo hump: Cortisol promotes fat redistribution to trunk and face
  • Purple striae, easy bruising, poor wound healing: Cortisol impairs collagen synthesis and increases capillary fragility
  • Muscle weakness, fatigue: Protein catabolism and muscle wasting due to cortisol excess
  • Hypertension, edema: Mineralocorticoid effects of cortisol leading to sodium retention
  • Hirsutism, acne, irregular menses: Excess androgen production from adrenal glands
  • Mood changes, depression, irritability: Direct effects of cortisol on central nervous system
• Examination
  • [Blood] Cortisol↑, loss of diurnal rhythm, glucose↑: Excess cortisol production and metabolic effects
  • [Blood] ACTH↓ (adrenal cause) or ACTH↑ (pituitary/ectopic cause): Feedback mechanism disruption
  • [Dexamethasone suppression test] Failure to suppress cortisol: Loss of normal negative feedback
  • [24-hour urine] Free cortisol↑: Reflects total cortisol production
  • [CT/MRI] Adrenal masses, pituitary adenoma: Identify source of excess cortisol/ACTH
  • [DEXA scan] Decreased bone density: Cortisol-induced bone loss
• Management
  • [Pituitary adenoma] Transsphenoidal surgery, gamma knife radiosurgery: Remove or destroy ACTH-secreting tumor
  • [Adrenal adenoma/carcinoma] Adrenalectomy: Remove cortisol-secreting tumor
  • [Ectopic ACTH] Surgical resection of primary tumor: Remove ACTH-secreting non-pituitary tumor
  • [Medical therapy] Ketoconazole, metyrapone, mitotane: Inhibit cortisol synthesis when surgery not possible
  • [Supportive care] Antihypertensives, antidiabetics, bisphosphonates: Manage complications of hypercortisolism

Adrenal Insufficiency / 副腎機能不全

• Overview
  • Inadequate production of adrenal hormones (cortisol ± aldosterone) due to adrenal gland dysfunction (primary) or pituitary-hypothalamic dysfunction (secondary)
  • Primary: Autoimmune destruction (Addison’s disease), TB infections
  • Secondary: Pituitary/hypothalamic disorders, prolonged corticosteroid use
  • Chronic condition that can progress to life-threatening adrenal crisis if untreated
• Presentation
  • Fatigue, weakness, weight loss, anorexia: Cortisol deficiency leads to decreased gluconeogenesis and reduced stress response
  • Hypotension, salt craving: Aldosterone deficiency causes sodium loss and potassium retention
  • Hyperpigmentation (primary only): Elevated ACTH stimulates melanocyte-stimulating hormone receptors
  • Nausea, vomiting, abdominal pain: Electrolyte imbalances and reduced cortisol affect GI function
• Examination
  • [Blood] Cortisol↓, aldosterone↓ (primary), ACTH↑ (primary), ACTH↓ (secondary): Hormone deficiencies and feedback mechanisms
  • [Blood] Na↓, K↑, glucose↓: Aldosterone deficiency causes electrolyte imbalance, cortisol deficiency affects gluconeogenesis
  • [ACTH stimulation test] Blunted cortisol response: Impaired adrenal cortisol production capacity
  • [CT/MRI] Small or atrophic adrenals (primary): Structural changes of adrenal gland
• Management
  • Hydrocortisone: Replace deficient glucocorticoid, mimics natural circadian rhythm
  • Fludrocortisone: Replace deficient mineralocorticoid to maintain electrolyte balance
  • [Adrenal crisis] IV hydrocortisone, IV fluids, electrolyte correction: Emergency treatment for life-threatening hormone deficiency

Pheochromocytoma / 褐色細胞腫

• Overview
  • Tumor of chromaffin cells in adrenal medulla (90%) or extra-adrenal paraganglia that secretes excessive catecholamines (epinephrine, norepinephrine)
  • Rare tumor affecting 0.1-0.2% of hypertensive patients, may be sporadic or familial (MEN2, VHL, NF1)
  • Can be benign (85-90%) or malignant, characterized by episodic or sustained catecholamine release
• Presentation
  • Headache, sweating, palpitations: Excessive catecholamine release causing sympathetic stimulation
  • Hypertension (sustained or episodic), tachycardia: Direct cardiovascular effects of catecholamine excess
  • Anxiety, tremor, panic attacks: Central nervous system effects of catecholamine excess
  • Chest pain, abdominal pain: Vasoconstriction and increased cardiac workload
• Examination
  • [Blood] Plasma metanephrines↑, catecholamines↑: Direct measurement of catecholamine metabolites and hormones
  • [Urine] 24-hour urine metanephrines↑, VMA↑, catecholamines↑: Catecholamine metabolites excreted in urine
  • [CT/MRI] Adrenal mass, heterogeneous enhancement: Tumor visualization in adrenal gland or extra-adrenal locations
  • [MIBG scan, PET scan] Uptake in tumor: Functional imaging using catecholamine analogs
• Management
  • Alpha-blockers (phenoxybenzamine, doxazosin): Block α-adrenergic receptors to control hypertension, must be started before β-blockers
  • Beta-blockers (propranolol, metoprolol): Block β-adrenergic receptors for heart rate control, added after α-blockade established
  • Surgical resection (laparoscopic adrenalectomy): Complete tumor removal is curative treatment, after preoperative preparation
  • [Hypertensive crisis] IV nicardipine, esmolol: Immediate blood pressure and heart rate control during catecholamine surge

Neuroendocrine Tumor / 神経内分泌腫瘍

Nephrology / 腎臓科

Hematology / 血液科

Rheumatology / リウマチ科

Infectious Diseases / 感染症科

Neurology / 神経科

Psychiatry / 精神科

Ophthalmology / 眼科

Otolaryngology / 耳鼻咽喉科

Dermatology / 皮膚科

Orthopedic Surgery / 整形外科

Urology / 泌尿器科

Gynecology / 婦人科

Obstetrics / 産科

Pediatrics / 小児科