肺炎合併膿胸之病因、診斷與治療

The Etiology, Diagnosis, and Treatment of Pneumonia with Empyema

膿胸是因感染引起的肋膜腔積膿，主要由肺炎導致，也可由鄰近組織感染或侵入性治療引起，膿液中含有大量免疫細胞、發炎物質、細胞殘骸及病原體，無法自行咳出，需通過引流或手術清除。膿胸分為滲出期、纖維化膿期和組織化期，從無菌液體積聚到細菌入侵引起膿液變得渾濁，最終形成纖維束和隔膜。臨床表現包括急性發燒、咳嗽、胸痛和呼吸困難，慢性膿胸特徵是間歇性低度發燒、體重減輕、呼吸困難和慢性咳嗽。診斷膿胸依賴影像學檢查和生化分析，胸部X光可顯示肋膈角和心膈角的變鈍，但若積液小於250毫升則難以檢測；超音波掃描可用於檢測最少量的液體(小至3至5mL)，並且比一般胸部X光檢查更敏感，典型表現為積液不均勻且無迴聲；胸部電腦斷層掃描顯示增強增厚的肋膜，表明纖維蛋白塗層和血管增生。生化分析部份，當膿胸存在時，液體的pH值通常小於7.2，葡萄糖濃度低於35 mg/dL，乳酸去氫酶超過1000 U/L，而白血球計數則超過15,000 count/mL。治療策略包括抗生素治療、胸管引流、血栓溶解劑和胸腔內視鏡輔助剝皮術。首選第2或第3代頭孢子菌素和clindamycin，院內感染可考慮使用vancomycin和meropenem。胸管引流適用於肋膜腔內膿性液體或胸水pH值小於7.2的情況，而血栓溶解劑和DNase組合治療則適用於纖維束和隔膜的情況。若其他治療無效，則需考慮進行胸腔內視鏡輔助剝皮術以改善治療效果。

Pleural empyema, a purulent collection in the pleural cavity caused by infection, is primarily due to pneumonia but can also result from adjacent tissue infections or invasive procedures. The pus contains numerous immune cells, inflammatory substances, cell debris, and pathogens that cannot be coughed out spontaneously and require drainage or surgical removal. Empyema progresses through exudative, fibrinopurulent, and organizing stages, starting with sterile fluid accumulation and progressing to bacterial invasion and turbid purulent fluid, eventually leading to fibrin strands and septations. Clinical manifestations include acute fever, cough, chest pain, and respiratory distress. Chronic empyema is characterized by intermittent low-grade fever, weight loss, respiratory difficulty, and chronic cough. Diagnosis of empyema relies on imaging studies and biochemical analysis. Chest X-ray may show blunting of the costophrenic and cardiophrenic angles, but it may not detect fluid volumes less than 250 ml. An ultrasound scan can be used to detect minimal amounts of fluid, as small as 3 to 5 mL, and is significantly more sensitive than a plain chest radiograph. Typical findings are of collections that are not uniformly anechoic and are often septate CT scan of the chest reveals enhanced thickening of the pleura indicating fibrin deposition and vascular proliferation. Biochemical analysis typically shows pleural fluid pH less than 7.2, glucose concentration less than 35 mg/dL, lactate dehydrogenase exceeding 1000 U/L, and white blood cell count exceeding 15,000 cells/mL when empyema is present. Treatment strategies include antibiotic therapy, chest tube drainage, fibrinolytic agents, and video-assisted thoracoscopic surgery (VATS). Preferred antibiotics include second or third-generation cephalosporins and clindamycin; vancomycin and meropenem may be considered for hospital-acquired infections. Thoracostomy drainage is indicated for purulent pleural fluid or pleural fluid pH less than 7.2, while fibrinolytic agents and DNase combination therapy are used for fibrin strands and septations. VATS may be considered if other treatments fail to improve outcomes.