Aspergillus Lung Disease

Question 1

How does aspergillus affect the lung

Answer 1

Asthma - Type I hypersensitivity reaction to aspergillus
Allergic bronchopulmonary aspergillosis (ABPA) - Type I and III hypersensitivity reaction to aspergillus fumigatus
Mycetoma (aspergilloma) - Formation of a aspergillus fungus plug within a pre-existing cavity.
Invasive aspergillosis - Inhalation of aerosolised conidia of Aspergillus, with the filamentous fungi being found in soil.
Extrinsic allergic alveolitis
Invasive aspergillosis: invasion of lung tissue → fungal dissemination

Question 2

Aetiology of aspergillus lung disease

Answer 2

Neutropenia and compromised T-lymphocyte/macrophage function predispose to infection
Humans routinely inhale the aerosolised conidia, but is promptly eliminated from the respiratory tract
Aspergillus fumigatus is the most common pathogenic species (+ flavus, terrus, niger, versicolor)

Question 3

Risk factors for aspergillus lung disease

Answer 3

Immunosuppression:
Allogeneic stem cell transplantation
Prolonged severe neutropenia (>10 days)
Immunosuppressive therapy
Chronic granulomatous disease
Solid organ transplantation
Acute leukaemia
Aplastic anaemia
Pre-existing cavity (aspergilloma)
Advanced chronic lung disease
Primary immunodeficiency
HIV infection
Diabetes mellitus
Cystic fibrosis
Severe burns
Malnutrition
Multiple myeloma
Immunocompetent patients
Age >55 years

Question 4

Symptoms of aspergillus lung disease

Answer 4

Wheeze
Productive cough ± haemoptysis (aspergilloma)
SOB
Recurrent pneumonia
Pleuritic chest pain (invasive)
General: lethargy, weight loss, fever, headache

Question 5

Signs of aspergillus lung disease on examination

Answer 5

Aspergilloma: tracheal deviation
ABPA: dullness in affected lung, wheeze
Invasive aspergillosis: cyanosis

Question 6

Investigations for aspergillus lung disease

Answer 6

Sputum culture: Aspergillus +

RAST: IgE aspergillus specific
Serology: raised IgE
FBC: eosinophilia

CXR:
- ABPA: transient segmental collapse | consolidation | bronchiectasis
- Mycetoma: round opacity within a cavity, usually apical, air crescent in periphery
- CXR: consolidation, abscess, nodules, infiltrates, pleural-based lesions
Aspergillus skint testing: +
CT chest:
- Mycetoma: Mass with intracavitary contents with adjacent pleural thickening
- Invasive aspergillosis: nodules 1cm or more in size with or without halo sign of air crescent sign
Biopsy: fibrosis, inflammatory cells
BAL: hyphal elements

Question 7

Management for aspergillus lung disease

Answer 7

ABPA
- oral glucocorticoids
- itraconazole is sometimes introduced as a second-line agent

Invasive aspergillosis
1. Reversal of the underlying immune deficiency
- Colony-stimulating factors may reduce the duration of neutropenia
- Discontinuing or reducing the dose of corticosteroids
2. Early introduction of antifungal therapy
- Voriconazole, posaconazole
- Amphotericin B
- Micafungin, caspofungin

Aspergilloma
1. Antifungal
- IV itraconazole/voriconazole
2. Haemoptysis → Bronchial artery embolisation
3. Life-threatening haemoptysis → surgical resection

Question 8

Complications of aspergillus lung disease

Answer 8

Life-threatening haemoptysis
Disseminated infection
Severe hypoxia
Obstructive pneumonia
Pericarditis