Interstitial Lung Disease
WHAT IS FIBROSING ALVEOLITIS?
Fibrosing alveolitis is a condition which is caused by cells, which are normally involved in the body’s own defense against infection, instead causing inflammation, injury and scarring in the lungs. Scars serve a good purpose in the skin where they heal injured areas but in the lung, scar tissue prevents the lung performing its normal function of taking oxygen from the air into the blood and removing carbon dioxide from the blood.
WHO CAN GET THE DISEASE?
Fibrosing alveolitis seems to be on the increase although it is not clear why this is so. It can affect people of any age but the most common age at which the disease strikes is in the 50s and men and women are equally affected. We do not know what causes Fibrosing alveolitis, but do know that it is not an infection, that it cannot be caught from others and neither is it a form of cancer. Exposure to certain occupational dusts (e.g. asbestos, hard metal alloy), can produce disease which is identical to fibrosing alveolitis and most people with the disease are or have been cigarette smokers. However, for most people the specific cause or provoking factors cannot be identified.
WHAT ARE THE SYMPTOMS?
The most common symptom is breathlessness, particularly on exercise such as walking up hills or stairs. Because it may come on in the mid 50s, patients often attribute this to middle age. It is important to stress that the onset of breathlessness should be investigated rather than to assume it is merely part of an ageing process. If it remains untreated the condition can often worsen and lead to permanent and progressive breathlessness. Less common symptoms include a dry cough, and some people may notice a change in the shape of their finger and toe nails. This feature is present in the majority of patients who develop this lung disease.
HOW IS THE DIAGNOSIS MADE?
Investigations will usually include a chest radiograph and a set of breathing tests. These require the individual to breathe in and out of a number of machines which allow an assessment to be made of how well the lungs are working. Blood tests are also usually performed. A special form of X-ray (known as a CT scan) which produces a three dimensional picture of the lungs, may be requested. It may be necessary to obtain samples of lung tissue for examination in the laboratory. This is usually done by bronchoscopy which involves passing a small flexible telescope down the breathing tubes with the patient lightly sedated. For many people these tests provide the necessary information for planning treatment, but in some people a larger sample of lung tissue, taken by a surgeon under a general anesthetic, is needed before treatment can be considered.
It is very important that the disease is identified and investigated at the earliest possible stage so that treatment to reduce progressive lung scarring can be considered at a time before the patient is severely disabled. The most common form of treatment is steroids, usually a short period of high dose therapy followed by a longer period of treatment on lower doses. A few people may experience side effects: therefore a very careful balance between the potential benefit of treatment and the risk of side effects needs to be weighed up before recommendations are made. Other drugs which may be used to treat the disease are known as immunosuppressants. Once maximum response has been achieved, the aim is to maintain that response while reducing therapy. The need for treatment in fibrosing alveolitis is usually lifelong. This is because the condition is suppressed rather than cured in the majority of cases and the long term aim is to keep the disease suppressed on the smallest possible dosage of treatment. Very occasionally drugs may be discontinued completely but this is the exception rather than the rule.
Occasionally lung transplantation might be the only option available fo these patients.