empyema

Empyema is the collection of pus within the pleural space, typically arising as a complication of pneumonia or thoracic infection. It progresses through three stages: an exudative stage with pleural fluid that is typically free-flowing, a fibrinopurulent stage with loculated pus, and an organizing stage characterized by pleural thickening and restrictive lung expansion.

Most cases originate from bacterial pneumonia, but empyema can follow chest surgery, trauma, aspiration, malignancy, or chest infections such as tuberculosis. Risk factors include advanced age, alcoholism, diabetes, chronic lung disease, and immunosuppression.

Patients commonly present with fever, chest pain, dyspnea, and productive cough. Physical examination may reveal reduced breath sounds and dullness to percussion. Imaging with ultrasound or CT detects effusions and loculations; chest radiographs may show a pleural fluid collection. Diagnostic thoracentesis yields purulent pleural fluid with low pH (less than about 7.2), low glucose, high LDH, and elevated white cell count; Gram stain and cultures guide antimicrobial therapy.

Management centers on antibiotics with activity against aerobic and anaerobic organisms and prompt drainage. Chest tube thoracostomy is standard; intrapleural fibrinolytics (such as tissue plasminogen activator) with DNase may improve drainage in loculated effusions. Failure or organized empyema may require video-assisted thoracoscopic surgery decortication or, rarely, open surgery. Prognosis improves with early recognition and adequate drainage, while delay increases morbidity and mortality.