Lung abscess

Background

Lobes of the lung with related anatomy.

• Localized, suppurative necrotizing process occurring within the pulmonary parenchyma
• Microbiology
  • Community-acquired: anaerobes mostly aspiration, anaerobic bacteria from oral cavity: peptostreptococcus, prevotella, bacteroides, fusobacterium species
  • Hospital-acquired: Staph, E coli, Klebsiella, pseudomonas, legionella

Causes

• Aspiration pneumonia (7-14 days to become lung abscess)
• Bacteremia from nonpulmonary infection
• Influenza leading to Bacterial superinfection (e.g. S. Aureus)
• Pulmonary infarction
• Infection as a result of penetrating chest trauma
• Primary and metastatic neoplasms
• Granulomatosis with polyangiitis (Wegener's), sarcoidosis

Clinical Features

• Cough, fever, pleuritic chest pain, weight loss, night sweats (generally over course of several weeks)
  • Tachycardia, tachypnea, or fever may be absent

Complications

• Empyema
• Massive hemoptysis

Differential Diagnosis

• Cavitary lesion with air-fluid level
• Infected bullae
• Pleural fluid collection with bronchopleural fistula
• Loop of bowel extending through diaphragmatic hernia

Evaluation

Pulmonary abscess on CXR

CXR showing pneumonia with lung abscess.

Pulmonary abscess on CT scan

• CXR or CT Chest
• Dense consolidation with air-fluid level inside of a thick-walled cavitary lesion
  • Air-fluid level indicates communication of abscess cavity with a bronchiole

Management

• Medical management will successfully treat 70-90% of lung abscesses
  • Drainage occurs spontaneously from communication of cavity with tracheobronchial tree
  • Bronchoscopic drainage may result in seeding other parts of the lung
• Antibiotics
  • Clindamycin + 2nd or 3rd gen cephalosporin OR
  • Clindamycin + ampicillin/sulbactam

Disposition

• Admit

See Also

• Empyema