Aspergillus lung disease

Question 1

Define

Answer 1

Lung disease associated with Aspergillus fungal infection

 

NOTE: Aspergillus infection is usually caused by Aspergillus fumigatus

Question 2

What are the different presentations?

Answer 2

1. Aspergilloma
2. Allergic bronchopulmonary aspergillosis
3. invasive aspergillosis
   can also present as asthma or extrinsic allergic alveolitis

Question 3

Describe aetiology of aspergilloma

Answer 3

Growth of an A. fumigates mycetoma ball in a pre-existing lung cavity (e.g. post-TB, old infarct or abscess)

Question 4

Describe aetiology of ABPA

Answer 4

Colonisation of the airways by Aspergillus leads to IgE and IgG-mediated immune responses (type I and II hypersensitivity reactions)

Usually occurs in asthmatics(1-5%) and CF (2-25%) pts

The release of proteolytic enzymes, mycotoxins and antibodies leads to airway damage, bronchoconstriction then permanent damage causes central bronchiectasis

Question 5

Describe aetiology of invasive aspergillosis

Answer 5

Invasion of Aspergillus into lung tissue and fungal dissemination

Risk factors: immunosuppressed patients (e.g. neutropenia, steroids, AIDS, leukaemia, burns, SLE or after broad spectrum antibiotics)

Question 6

How does aspergilloma present?

Answer 6

ASYMPTOMATIC

Cough, lethargy, weight loss, haemoptysis (potentially massive)

Question 7

How does ABPA present

Answer 7

Difficult to control asthma

Recurrent episodes of pneumonia

wheeze, cough, sputum (plugs), dyspnoea, malaise

Question 8

How does invasive aspergillosis present?

Answer 8

Dyspnoea

Fever, cough

Rapid deterioration

Septic picture

Question 9

How would you investigate aspergilloma?

Answer 9

CXR

May show a round mass with a crescent of air around it

Usually found in the upper lobes

CT or MRI - may be used if CXR is unclear

Aspergillus skin test (30% positive)

NOTE: sputum cultures may be negative if there is no communication between the cavity colonised by Aspergillus and the bronchial tree

Question 10

How would you investigate ABPA?

Answer 10

Immediate skin test reactivity to Aspergillus antigens

Eosinophilia

Raised total serum IgE

Raised specific serum IgE and IgG to A. fumigatus

• CXR

Transient segmental collapse/ consolidation

Distended mucous-filled bronchi

Signs of complications:

Fibrosis in upper lobes

Bronchiectasis

• CT

Lung infiltrates

Central bronchiectasis

Question 11

How would you investigate invasive aspergillosis?

Answer 11

CXR (nodules, consolidation)

High resolution chest CT

Nodules surrounded by a ground-glass appearance (halo sign)

This is caused by haemorrhage into the tissue surrounding the fungal invasion

Bronchoalveolar lavage fluid or sputum culture

Serial serum measurements of galactomannan (an aspergillus antigen)

Diagnosis only made by lung biopsy