Aspergillosis is an infection caused by the fungus Aspergillus. Aspergillosis describes a large number of diseases involving both infection and growth of fungus as well as allergic responses. Aspergillosis can occur in a variety of organs, both in humans and animals.
The most common sites of infection are the respiratory apparatus (lungs, sinuses) and these infections can be:
- Invasive (e.g. Invasive Pulmonary Aspergillosis - IPA)
- Non-invasive (e.g. Allergic Pulmonary Aspergillosis - ABPA)
- Chronic pulmonary and aspergilloma (e.g chronic cavitary, semi-invasive)
- Severe asthma with fungal sensitisation (SAFS)
Chronic pulmonary aspergillosis - CPA is a long-term aspergillus infection of the lung and Aspergillus fumigatus is almost always the species responsible for this illness. Patients fall into several groups as listed below.
- Those with an aspergilloma which is a ball of fungus found in a single lung cavity - which may improve or disappear, or change very little over a few years.
- Chronic cavitary pulmonary aspergillosis (CCPA) where cavities are present in the lungs, but not necessarily with a fungal ball (aspergilloma).
- Chronic fibrosing pulmonary aspergillosis this may develop where pulmonary aspergillosis remains untreated and chronic scarring of the lungs occurs. Unfortunately scarring of the lungs does not improve.
Most patients with CPA have or have had an underlying lung disease. The most common diseases include tuberculosis, atypical mycobacterium infection, stage III fibrocystic pulmonary sarcoidosis, ABPA, lung cancer, COPD and emphysema, asthma and silicosis.
The specific criteria for diagnosis of CPA are:
- Chest X-rays showing one or more lung cavities. There may be a fungal ball present or not.
- Symptoms lasting more than 3 months, usually including weight loss, fatigue, cough, coughing blood (haemoptysis) and breathlessness
- A blood test or tissue fluid test positive for Aspergillus species
An aspergilloma is a fungal mass caused by a fungal infection with Aspergillus species that grows in either scarred lungs or in a pre-existing lung cavity, which may have been caused by a previous infection. Patients with a previous history of tuberculosis, sarcoidosis, cystic fibrosis or other lung disease are most susceptible to an aspergilloma. Aspergillomas may have no specific symptoms but in many patients there is some coughing up of blood called haemoptysis - this may be infrequent and in small quantity, but can be severe and then it requires urgent medical help.
Tests used to diagnose an aspergilloma may include:
- Chest X-ray
- Chest CT
- Sputum culture
- Bronchoscopy or bronchoscopy with lavage (BAL)
- Serum precipitins for aspergillus (blood test to detect antibodies to aspergillus)
Almost all aspergillomas are caused by Aspergillus fumigatus. In diabetic patients it may be caused by Aspergillus niger. It is very rarely caused by Aspergillus flavus, Aspergillus oryzae, Aspergillus terreus or Aspergillus nidulans.
Patients with single aspergillomas generally do well with surgery to remove the aspergilloma, and are best given pre-and post-operative antifungal drugs. Often, no treatment is necessary. However, if a patient coughs up blood (haemoptysis), treatment may be required (usually angiography and embolisation, surgery or taking tranexamic acid). Angiography (injection of dye into the blood vessels) may be used to locate the site of bleeding which may be stopped by shooting tiny pellets into the bleeding vessel.
For more complex, chronic cases, lifelong use of antifungal drugs is usual, along with chest X-rays to monitor progress. It is important to monitor the blood levels of antifungals to ensure optimal dosing as individuals vary in their absorption levels of these drugs.