CPA – 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. Sufferers of CPA have healthy immune systems which under usual circumstances would completely eradicate an infection by this fungus. Consequently the infection cannot rapidly invade the patient but manages to inhabit areas of the body where it can find a toehold.
Suitable areas of the body are where the fungus has first managed to gain access – so the airways of the lungs or sinuses are common as fungal spores travel well in air. Secondly it needs to evade the immune system, so tends to inhabit cavities where there is less contact with the immune system, such as damaged lung tissue left behind by tuberculosis or similar infection/damage. The debris left behind by the original infection provides the ‘toehold’ the fungus needs.
Once established the fungus can grow slowly, limited by the surrounding tissue where the immune system of the patient still attacks it whenever it touches the sides of the cavity. It can lie hidden for years giving few symptoms, but in some cases can start to erode surrounding tissue, perhaps because of scarring caused by inflammation where the fungus touches the sides. This is how a fungal ball, also called an aspergilloma, develops – usually in a pre-existing cavity initially caused by another illness. Not all CPA patients develop an aspergilloma.
This is not immediately health-threatening unless a major blood vessel is eroded whereupon bleeding occurs, occasionally causing heavy blood loss which is called haemoptysis. In this situation immediate hospital treatment is required.
Aspergillomas may have few specific symptoms but 50-90% of patients experience some coughing up of blood.
For other CPA sufferers it is may include weight loss, fatigue, cough, haemoptysis (bleeding in the lungs) and breathlessness, usually for a period longer than 3 months.
Most patients with CPA have an underlying lung disease. These include TB, previous treatment for lung cancer, sarcoidosis, emphysema and COPD. Chest X-rays or CT scans may show one or more lung cavity, and blood tests may be positive for aspergillus antibodies. An assay called the galactomannan assay is a more reliable test for aspergillus exposure. A sample of sputum may be cultured in an attempt to see if Aspergillus grows out. Occasionally a biopsy is taken & tested.
Diagnosis is difficult and often requires a specialist. This is one of the main services offered by the National Aspergillosis Centre in Manchester, UK, where advice can be sought.
Patients with single aspergillomas generally do well with surgery and are best given pre- and post-operative antifungals to prevent other complications. For more complex cases (CCPA) lifelong use of antifungals is normal along with regular X-rays to observe progress. It is important to monitor the blood levels of antifungals to ensure optimal dosing as individuals vary in how they take in these drugs.
If bleeding is occurring and surgery is not possible then other treatments can be used to limit blood loss. For example, tranexemic acid can be given to encourage clotting and if that fails, and bleeding becomes excessive, embolisation is carried out via a catheter (see talk about limiting blood loss by Consultant Radiologist at National Aspergillosis Centre Ray Ashleigh).
Some spontaneously disappear (less than 10%) and most (84%) do well after surgery (if they can have it) but for the rest this is a lifelong illness.
Chronic Pulmonary Aspergillosis (CPA) and Chronic Invasive Pulmonary Aspergillosis (CIPA) have both been used in the past and this caused confusion. CIPA is now officially no longer used to describe this illness.
Chronic Pulmonary Aspergillosis covers at least three subcategories of chronic infection:
- Chronic Cavitary Pulmonary Aspergillosis (CCPA) which is defined by one or more cavities which may or may not have a fungal ball present in the cavities.
- Aspergilloma is the term used for a fungal ball growing in a cavity. A CPA patient with an aspergilloma may see an improvement or little change over a few years. There may be few symptoms or just a cough.
- Chronic Fibrosing Pulmonary Aspergillosis (CFPA) is essentially a CCPA that has got to a late stage in its development and the lung is heavily scarred.
There is a definitive article describing all aspects of CPA on the Aspergillus Website. Written by Professor David Denning, Director of the National Aspergillosis Centre it is intended for people with medical training.