The lungs are part of the respiratory system and are responsible for breathing. These spongy organs contain a network of airways called bronchi that branch into smaller tubes called bronchioles that end in tiny air sacs called alveoli. The lungs are delicate and are susceptible to damage and scarring by a variety of diseases and disorders.
Interstitial Lung Disease
Interstitial lung disease is the name for a group of disorders, which are described below (see Reference 2). There are many causes of interstitial lung disease, but usually the disease progresses causing scarring of the lung tissue. The scar tissue on the lungs affects the lungs' function and is irreversible.
Occupational and Environmental Factors
Long-term exposure to toxins and pollutants such as silica dust or asbestos increases your risk of lung disease that can lead to scar tissue. Other substances such as grains, sugar cane, animal droppings, dust and moulds can also damage the lungs.
Viral infections such as cytomegalovirus, fungal infections such as histoplasmosis and even bacterial infections such as pneumonia can cause disease in the lungs that can lead to further damage and scarring.
Patients receiving radiation therapy to treat cancer are at risk for lung damage. The extent of the damage and whether scar tissue forms on the lungs is dependent on several factors, including the health of the lungs and the dose and length of the radiation treatments.
Certain prescription medications--including chemotherapy drugs, heart drugs, psychiatric medications and even some antibiotics--can cause damage to the lungs. The damage caused by medications is rarely permanent, but those with underlying lung disorders are at risk of developing scar tissue.
Pulmonary fibrosis is a chronic lung disease involving the abnormal formation of fibre-like scar tissue in the lungs. In the early stages of the disease, the lungs can become inflamed, making breathing difficult. As the disease progresses, the lungs' air sacs (alveoli) can become twisted out of shape, causing the capillaries to become distorted and interrupting blood flow to the lungs. The disease can remain mild, causing few symptoms, or progress to the point that scar tissue builds up and becomes fatal.
Treatment depends upon the disease and the extent of the damage. Once scarring has occurred, it is irreversible. If the cause is an environmental factor, cessation of the exposure will prevent further damage. Anti-inflammatory medication such as corticosteroids can help to temporarily relieve the symptoms caused by scarring. There are medications in clinical studies, called anti-fibrotics, that help reduce the development of scar tissue.