LUNG ABSCESS

Lung abscess is a clinical condition characterized by focal suppurative necrosis of lung parenchyma. The incidence of lung abscess is unknown. Current concepts suggest that most lung abscesses occur as a complication of aspiration pneumonia and are often attributed to anaerobic organisms from the gingival crevices of the oral cavity. Patients typically present with indolent onset of fever, malaise, night sweats, weight loss, cough, pleurisy, and purulent sputum production, of several weeks duration and often with an antecedent history of loss of consciousness or aspiration. The chest radiograph typically demonstrates parenchymal radiolucency with surrounding thick wall, or a radiolucency with an air–fluid level, and may require chest CT to confirm the diagnosis. Anaerobic bacteria frequently account for the majority of community-acquired lung abscess cases (often polymicrobial), whereas anaerobes may account for most cases of hospital-acquired lung abscess (often a single pathogen). Evaluation of sputum is controversial and blood cultures are rarely positive, so isolating the etiological agent often requires invasive techniques. Treatment includes prolonged antimicrobial therapy, and in general, the prognosis is favorable. Surgical resection is reserved for patients with poor clinical responses. Techniques of percutaneous or endobronchial drainage may be effective alternatives for select patients with poor clinical responses who are considered high surgical risk.