Fungal Infections in the Lung

• Aspergillus can affect the lung in 5 ways;

Asthma – a type I hypersensitivity response to fungal spores

Allergic bronchopulmonary aspergillosis (ABPA)

• Results from Type I and III reactions to Aspergillus fumigatus.
• Early response leads to bronchoconstriction, but as the inflammation persists, permanent damage occurs leading to bronchiectasis
• Symptoms – wheeze, cough, sputum containing plugs of hypae, dyspnoea, recurrent pneumonia
• Investigations;
  • CXR – transient segmental collapse or consolidation, bronchiectasis
  • Sputum – aspergillus
  • IgE aspergillus spp RAST
  • Positive serum precipitans
  • Eosinophilia
  • Raised IgE
• Treatment – prednisolone 30-40mg for acute attacks, 5-10mg for maintenance
  • Bronchodilators for asthma

Aspergilloma

• A fungus ball within a pre-existing cavity (often caused by TB or sarcoidosis)
• Usually asymptomatic but may cause cough, haemoptysis, lethargy, weight loss
• Investigations – CXR (generally apical), sputum culture, strongly positive serum precipitans, aspergillus skin test

Treatment – only if symptomatic, consider surgical exision. Local instillation of amphotericin paste under CT guidance yields partial success in selected patients

Invasive aspergillosis

• Risk factors;
  • Immunocompromise – HIV, leukaemia
  • Burns
  • Wegeners, SLE
  • After broad spectrum antibiotics
• Investigations – sputum culture, serum precipitins, CXR
• Treatment – IV amphotericin B
• Prognosis is very poor

Extrinsic allergic alveolitis

• Caused by sensitivity to Aspergillosis clavatus – ‘malt worker lung’
• Diagnosis based on serum precipitans to A.clavatus
• Pulmonary fibrosis may occur if untreated