132.1 🎓 醫孞生版

132.1.0.1 📌 䞀頁重點

  • 病因: 倚 aspiration of oropharyngeal flora (anaerobes); 2nd: bronchial obstruction (cancer, foreign body), septic embolism (IVDU, IE), bacteremia
  • 病原: anaerobes (Bacteroides, Prevotella, Fusobacterium, Peptostreptococcus); aerobes (S. aureus, K. pneumoniae, Streptococcus); 免疫䜎䞋 (Pseudomonas, Aspergillus, Nocardia, fungi, mycobacteria)
  • 特埵: insidious 1-3 週癌展; foul-sputum (anaerobes); cavity > 2 cm with air-fluid level on CXR/CT
  • 治療: 4-6 週 antibiotic (longer if large/complex); first-line: amoxicillin-clavulanate OR clindamycin; surgical drainage rarely需芁 (90% medical management 即可)

132.1.0.2 1⃣ 病因分類

132.1.0.2.1 A. Primary (Aspiration)
  • 最垞芋 (70-80%)
  • Risk: 意識䞋降 (alcohol, drug, seizure, anesthesia), dysphagia (stroke, dementia, esophageal disease), poor dental hygiene, GERD
  • 䜍眮: 䟝 aspiration position
    • 臥姿 (supine): 䞊葉 posterior + 䞋葉 superior segments
    • 盎立: lower lobes basal segments
    • 右肺倚 (right main bronchus 范盎)
132.1.0.2.2 B. Secondary
  • Bronchial obstruction: cancer, foreign body
  • Septic embolism: IVDU (right-sided IE → S. aureus), Lemierre syndrome (Fusobacterium → IJ vein thrombus)
  • Hematogenous: bacteremia from any source
  • Adjacent: subdiaphragmatic abscess extension
132.1.0.2.3 C. Immunocompromised
  • 病原 broader: Pseudomonas, Aspergillus, Nocardia, Cryptococcus, mycobacteria (TB, NTM), pulmonary mucormycosis
  • Often severe, multi-cavity, slower response

132.1.0.3 2⃣ 臚床衚珟

  • Insidious: weeks of fever, cough, weight loss, night sweats
  • Foul-smelling sputum (anaerobic — pathognomonic)
  • 痰液 putrid, may be hemoptysis
  • Halitosis
  • Clubbing (chronic)
  • Examination: amphoric breath sounds over cavity (if > 4 cm)

132.1.0.4 3⃣ 蚺斷

132.1.0.4.1 CXR / CT
  • CXR: cavity ≥ 2 cm with air-fluid level
  • CT: better — defines size, cavity wall, air-fluid level, surrounding parenchyma, bronchial obstruction (mass), associated lymphadenopathy
132.1.0.4.2 Microbiology
  • Sputum Gram + culture (limited)
  • Bronchoscopy + BAL/protected brush — reasonable for atypical or refractory
  • Blood cultures × 2
  • TB workup: AFB smear + culture + GeneXpert; rule out always!
  • HIV test in unexpected presentation
132.1.0.4.3 鑑別 (cavity on CT)
  • Bacterial abscess (本章)
  • TB (䞊葉)
  • Fungal (Aspergilloma, Histoplasma)
  • Cancer cavitation (squamous cell)
  • Vasculitis (GPA Wegener)
  • PE infarction
  • Septic embolism
  • Bullous emphysema with infection

132.1.0.5 4⃣ 治療

📖 䞭文抂念說明肺膿瘍幟乎郜靠 antibiotic + bronchoscopy 解決倖科 < 10%。臚床決策䞉鐵則(1) 療皋至少 4-6 週倪短會埩癌(2) è¿œ serial CXR 看 air-fluid level 消倱 (cavity 殘留可接受)(3) 劂果 6 週治療倱敗 → 䞀定芁排陀 bronchial obstruction (CT + bronchoscopy) — cancer 或 foreign body 䞍解陀膿瘍䞍會奜。Metronidazole 䞍可單獚䜿甚 是國考高頻陷阱題 — 對 microaerophilic Streptococcus 無效必須與 β-lactam 合甚或甚 ampicillin-sulbactam / amox-clav 取代。

132.1.0.5.1 Antibiotic (medical, 90% sufficient)
嚎重床 治療
Mild-moderate, primary Amoxicillin-clavulanate 875/125 BID PO × 4-6 wk
OR Clindamycin 600 mg IV q8h → 300 mg PO QID × 4-6 wk
Hospitalized / severe Ampicillin-sulbactam 3g IV q6h OR Pip-tazo OR Carbapenem + 考慮 vanco/linezolid (MRSA risk)
Specific / failed empirical adjust per culture; long course

⚠ Metronidazole alone 䞍倠 — 䞍對 microaerophilic Streptococcus

132.1.0.5.2 Duration
  • 4-6 週最少
  • 若 large > 6 cm, 倚 cavity, immunocompromised → 2-3 months
  • Resolution monitor with serial CXR (no air-fluid level → 治療成功)
  • Cavity may persist (residual) — 䞍必延長 antibiotic if clinically improved
132.1.0.5.3 Surgical / Procedural
  • 倧倚 䞍需芁 surgical drainage
  • Indications: 治療 6 週倱敗、巚型 abscess > 8 cm 持續, 嚎重 hemoptysis, 治療反應差, malignant component
  • Percutaneous drainage (CT-guided): for large/peripheral
  • Surgical resection (lobectomy): rare; reserved for refractory
132.1.0.5.4 Bronchoscopy
  • Both diagnostic + therapeutic
  • 排陀 bronchial obstruction (cancer, foreign body)
  • Drain proximal cavity (selective lavage)
  • Specimen for culture