The ubiquitious fungus

Evaluating a patient with difficult asthma this morning, my registrar asked me about ABPA. Aspergillus-related lung disease is poorly understood by doctors in training, and a little bit complicated. Allergic broncho-pulmonary aspergillosis is by-far the commonest manifestation of aspergillus disese which I encounter.

Aspergillus occurs in the lungs in the following ways:

1. Commensal in people with intact immunity and chronic lung disease

2. Aspergilloma in people with cavitating lung disease (old TB, emphysema); no treatment is usually required (the risks of surgery outweighing the benefit).

3. Chronic pulmonary aspergillosis; in people with chronic lung disease and mildly impaired immunity - for example on glucocorticoids. There is some invasion of lung parenchyma, and antifungal therapy may be required.

4. Allergic bronchopulmonary aspergillosis. IgE mediated sensitivity to the fungal spores, usually presents as difficult - to - control asthma. Any one or all of the following clincial features may occur; migratory lung infiltrates, peripheral blood eosinophilia, proximal bronchiectasis. Diagnosis depends on demonstrating the immunological response to aspergillus - not on demonstrating aspergillus in the airway. IgE is elevated about 1000, RAST or skin-prick sensitivity to aspergillus is evident. Treatment is targetted at the immune response (with glucocorticoids) and at antigen reduction. In regard to the latter, the only good evidence is for the benefit of itraconazole for up to 4 months at a dose of 200mg bd. Itraconazole is not on the PBS in Australia for this indication. Success of treatment is measured by clincal response and pulmonary physiology, and perhaps also by monitoring total IgE. A trial underway at the Alfred Hospital in Melbourne is evaluating the efficacy of the anti-IgE monoclonal antibody Omalizumab in treatment of ABPA.

5. Invasive aspergillosis occurs in patients with severely compromised immunity - for example bone marrow transplant recipients. Aggressive treatment with antifungals is required.

Glad to have clarified all that.

Andrew