LUNG ABSCESS

Localised inflammation and necrosis (destruction) of lung tissue leading to pus formation. It is most commonly
caused by aspiration of oral secretions by patients who have impaired consciousness.

Cause

  • Infection of lungs with pus forming organisms: e.g. Klebsiella pneumoniae, Staphylococcus aureus

Clinical features

  • Onset is acute or gradual
  • Malaise, loss of appetite, sweating with chills and fever
  • Cough with purulent sputum, foul-smelling breath (halitosis)
  • Chest pain indicates pleurisy
  • Finger clubbing

Complications

  • Pus in the pleural cavity (empyema)
  • Coughing out blood (haemoptysis)
  • Septic emboli to various parts of the body, e.g. brain (causing brain abscess)
  • Bronchiectasis (pus in the bronchi)

Differential diagnosis

  • Bronchogenic carcinoma
  • Bronchiectasis
  • Primary empyema communicating with a bronchus
  • TB of the lungs
  • Liver abscess communicating into the lung

Investigations

  • Chest X-ray
    • Early stages: Signs of consolidation
    • Later stages: A cavity with a fluid level
  • Sputum: For microscopy and culture and sensitivity

Management

  • Benzylpenicillin 1-2 MU IV or IM every 4-6 hours
    Child: 50,000-100,000 IU/kg per dose (max: 2 MU)
  • Plus metronidazole 500 mg IV every 8-12 hours
    Child: 12.5 mg/kg per dose

Once improvement occurs, change to oral medication and continue for 4-8 weeks

  • Metronidazole 400 mg every 12 hours
    Child: 10 mg/kg per dose
  • Plus Amoxicillin 500 mg-1 g 8 hourly
    Child: 25-50 mg/kg per dose for for 4-6 weeks
  • Postural drainage/physiotherapy
  • Surgical drainage may be necessary

Prevention

  • Early detection and treatment of pneumonia