Aspergillus Lung Disease

Question 1

Define Aspergillus and summarise epidemiology

Answer 1

Definition: Lung disease associated with Aspergillus fungal infection
NOTE: Aspergillus infection is usually caused by Aspergillus fumigatus

Epidemiology: Uncommon, mainly occurs in the elderly and immunocompromised.

Question 2

Summarise the aetiology for Aspergillus Lung Disease

Answer 2

Inhalation of Aspergillus spores can produce THREE different clinical pictures:
- Aspergilloma: Growth of an A.fumigates mycetoma ball in a pre-existing lung (e.g. post-TB, old infarct or abcess)

• Allergic Bronchopulmonary Aspergillosis (ABPA): Colonisation of airways by Aspergillus leads to IgE and IgG- mediated immune responses. Usually occurs in asthmatics. The release of proteolytic enzymes, mycotoxins and antibodies leads to airway damage and central bronchiectasis.
• Invasive Aspergillosis: Invasion of Aspergillus into lung tissue and fungal dissemination. This occurs in immunosuppressed patients (e.g. neutropenia, steroids, AIDS)

Question 3

Describe the history/presenting symptoms of Aspergillus lung disease

Answer 3

Aspergilloma: - Asymptomatic, haemoptysis (potentially massive).

ABPA:

• Difficult to control Asthma.
• Recurrent episodes of pneumonia with wheeze, cough, fever and malaise.

Invasive Aspergillosis:

• Fever
• Headache
• Cough
• Congestion or sinus tenderness
• Dyspnoea
• Rapid deterioration
• Septic picture

Question 4

Recognise the signs of Aspergillus lung disease on physical examination.

Answer 4

• Tracheal deviation (only with very large aspergillomas)
• Dullness in affected lung
• Reduced breath sounds
• Wheeze (in ABPA)
• Cyanosis (possible in invasive aspergillosis).

Question 5

What investigations are used to identify general Aspergillus lung disease

Answer 5

1st investigations to order:

• CXR
• High-resolution chest CT scan
• High-resolution sinuses CT scan
• High-resolution brain CT scan

Investigations to consider

• Serology
• Bronchoscopy with bronchoalveolar lavage (BAL) fungal stain
• Bronchoscopy with BAL fungal culture
• Tissue biopsy

Question 6

Summarise the risk factors for Aspergillus disease

Answer 6

• Allogeneic stem cell transplantation
• Prolonged severe neutropenia (>10 days)
• Immunosuppressive therapy chronic granulomatous disease (CGD)

Question 7

Identify appropriate investigations for Aspergilioma

Answer 7

CXR- May show a round mass with a crescent of air around it. Usually found in the upper lobes.

CT/MRI used if CXR is unclear
NOTE: sputum cultures may be negative if there is no communication between the cavity colonized by Aspergillus and the bronchial tree.

Question 8

Identify appropriate investigations for ABPA

Answer 8

• Immediate skin test reactivity to Aspergillus antigens.
• Eosinophilia
• Raised total serum IgE
• Raised specific serum IgE and IgG to A fumigatus.

CXR:

• Transient patchy shadow
• Collapse
• Distended mucous-filled bronchi
• Signs of complications: (fibrosis in upper lobes and bronchiectasis)

CT:

• Lung infiltrates
• Central bronchiectasis

Lung Function Tests:

• Reversible airflow limitation
• Reduced lung volumes/ gas transfer

Question 9

Identify appropriate investigations for Invasive Aspergillosis

Answer 9

• Aspergillus is detected in cultures or by histological examination.
• Bronchoalveolar lavage fluid or sputum may be used diagnostically

Chest CT:

• Nodules surrounded by a ground-glass appearance (halo sign)
• This is caused haemorrhage into the tissue surrounding the fungal invasion.