Medical Microbiology and Infection

at a Glance

Fourth EditionStephen Gillespie and Kathleen Bamford

Case Studies

Case 6

A 65-year-old patient who migrated to the UK from Gujerat presents with cough, producing blood-stained sputum and occasional mild fevers. A detailed history reveals that the patient had received a course of antibiotics for a chest complaint for a number of months 20 years ago. The sputum is sent to the laboratory for culture and it is reported that a filamentous fungus has been grown.

  • 1. What is the likely explanation for this?

    Although it is possible that this may be a contaminant, because the patient is symptomatic it is more likely that an old tuberculous cavity has been colonized by Aspergillus spp., which have formed a fungal ball – an aspergilloma. This can invade blood vessels causing haemorrhage and haemoptysis. The results of the mycobacterial cultures should also be reviewed carefully.

  • 2. How would you investigate this?

    A chest X-ray may show a mass surrounded by a halo – the characteristic radiological feature of an aspergilloma. Aspergillomas are better visualised using CT scan. Measurement of serum precipitins and galactomannan will also be useful and would be expected to be positive.

  • 3. What are the treatment options?

    If possible, surgical management to remove the fungal ball is the optimal treatment. Haemoptysis can be treated by embolization to infarct the aspergilloma and prevent bleeding from the vessels involved. Long-term antifungal therapy with activity against Aspergillus spp. is the only other option.

  • 4. What other ways can Aspergillus spp. cause infection.

    Aspergillus fumigatus is the commonest species causing human disease. As well as causing an aspergilloma, it can cause invasive infection in immunocompromised patients, most often affecting the respiratory tract in patients with neutropenia. These patients may also suffer from an invasive form of aspergillosis, which starts in the nasal sinuses. It can also cause bronchopulmonary aspergillosis (a type I hypersensitivity reaction to a colonized respiratory tree) and Farmers lung (a type III hypersensitivity reaction with fever shortness of breath and progressive pulmonary fibrosis).
    Aspergillus niger can cause otitis externa.

  • 5. What antifungal agents are suitable for treatment of pulmonary aspergillosis?

    Voriconazole is probably the treatment of choice. Liposomal amphotericin B should also have some activity.

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