Fibrosing alveolitis
Overview
The lungs are found in the chest, on either side of the heart, beneath the protective rib cage. They are made up of a series of branching tubes (the bronchi) leading all the way down from the main windpipe (trachea) to the system of air sacs (alveoli). This is where the exchange of gases takes place. In the alveoli oxygen is absorbed from the breathed air, through their walls into the bloodstream. Normally the lungs are able to expand and shrink with breathing, enabling air to be drawn in and out. Fibrosing alveolitis (FA) is a condition in which these walls of the lung tissues become thickened. This thickening impairs the ability of the lungs to expand, with the result that less air can be breathed in. This results in less absorption of oxygen into the bloodstream and leads to breathlessness
Symptoms
* The commonest symptoms are progressively increasing shortness of breath and dry cough. * 5% of patients diagnosed opportunistically have no initial symptoms. * 50% of patients are systemically unwell and may have a flu like illness, fatigue or weight loss. * Spontaneous remissions do not occur (in contrast to sarcoidosis). * Extrapulmonary features may include arthralgia, muscle pains and skin rashes.
Causes
The cause of this condition is still not known. It is probably the result of overactivity of the body's immune system causing damage to the lungs. The trigger for this self-damaging (auto-immune) process is not known, but may be multiple.