pulmonary abscess

Etiology

• most frequently following aspiration of oropharyngeal contents containing large numbers of anaerobes
• gingival & dental disease predispose to lung abscess formation
• pathogens
  • anaerobic bacteria (30-50%)
  • aerobic gram-positive bacteria (25%)
  • aerobic gram-negative bacilli ( 5-12%)
• opportunistic infections:
  • newborns with congenital cardiopulmonary disorders
  • elderly patients with blood dyscrasias
  • cancer of the lung or oropharynx
• nosocomial/iatrogenic
  • steroid therapy
  • post-operative
• hematogenous lung abscess
  • septicemia
  • septic embolism
  • sterile infarcts

Clinical manifestations

• foul smelling, purulent sputum
• fever
• weight loss
• hemoptysis
• cough

Laboratory

• leukocytosis
• sputum culture for:
  • Mycobacterium tuberculosis
  • fungi
• skin testing
• bronchoscopy
  • if obstruction suspected from tumor or foreign body
  • cultures
  • drainage

Complications

• rupture into the pleural space causing empyema

Differential diagnosis

• tuberculosis
• fungal disease
• acute necrotizing pneumonia
  • Staphylococcus aureus
  • gram negative bacilli
• carcinoma
• vasculitis
• septic embolism
• pulmonary embolism with infarction

Management

• drainage of involved segment
  • postural with physiotherapy
  • bronchoscopy may be necessary for abscess drainage
• antibiotics
  • penicillin G 1.5-2.0 million units IV every 4 hours; switch to Penicillin VK 500 mg PO every 6 hours once definite clinical response;
    • continue until cavity closes
  • ampicillin sulbactam
  • clindamycin
  • duration of therapy: at least 4-6 weeks
• healing may take 6-12 months
• surgical resection or percutaneous drainage rarely required
  • persistent fevers & leukocytosis despite therapy
  • bronchopulmonary fistula
  • empyema
  • hemoptysis (persistent)
  • enlarging abscess cavity
  • mechanical ventilation dependence

More general terms

• pulmonary infection
• abscess

Additional terms

• empyema