Interstitial Lung Disease (ILD)
Interstitial lung disease (ILD) is a disease that occurs when scar tissue forms in the interstitium – the space between the lungs' air sacs (alveoli). ILD is also known as interstitial pulmonary fibrosis, pulmonary fibrosis, lung fibrosis or interstitial fibrosis.
When ILD occurs as a result of exposure to asbestos, it is called asbestosis. There is evidence to suggest that it may be caused exposure to erionite (a mineral similar to asbestos) as well. Its main symptoms are difficulty breathing and dry cough.
The process that leads to interstitial lung disease begins when the tissue of the lungs is damaged and the walls of the alveoli become inflamed. Sometimes this inflammation heals, but when it doesn't it can lead to scarring (fibrosis) in the space between the air sacs. This in turn causes the lungs to become stiff and prevents them from properly transporting oxygen. The level of injury and discomfort associated with ILD depends on the amount of scarring.
There are more than 100 known causes of interstitial lung disease. They include, among others:
- Exposure to asbestos
- Drug reactions
- Heart failure
- Sarcoidosis (formation of granulomas [inflamed cells] that can attack the lungs)
- Radiation (from cancer treatment)
- Connective tissue/collagen diseases (rheumatoid arthritis, systemic sclerosis, etc.)
- Genetics (this is rare)
- Allergic reactions (one example is "farmer's lung," a reaction to moldy hay)
ILD Due to Asbestos Exposure (Asbestosis)
Asbestosis is the name used for interstitial lung disease that is caused by asbestos. Unlike malignant mesothelioma, asbestosis is not a form of cancer. Nonetheless, it can lead to disability and death, and even if it doesn't, some patients later develop mesothelioma and die.
Asbestosis and other asbestos-related diseases occur because, unlike most substances, asbestos fibers are small enough to evade the natural filtration system of the lungs. Once this happens, they can reach the inner regions of the lungs and become imbedded in the interstitium and other areas. Asbestos-related diseases commonly affect people who worked for long periods of time in professions where asbestos was used, as well as their families (due to secondary asbestos exposure).
Oftentimes, the first symptom of interstitial lung disease is difficulty breathing during exercise. Dry cough is the other common symptom. Both of these symptoms are associated with various types of ILD and can be mild or severe. In addition, different forms of ILD appear the same on the X-rays taken to identify what type of ILD a patient has. Absent a thorough patient history, it can be difficult for doctors to identify the cause of interstitial lung disease.
The following tests may be conducted by your doctor in order to confirm or rule out ILD:
- Blood tests
- Pulmonary function tests
- Chest x-rays
- CT scans
- Bronchoalveolar lavage
- Lung biopsy
These tests help doctors determine if you have lung damage and identify the cause. Some findings, such as the presence of plaque on the membranes that surround your lungs (pleural plaque) or a thickening of the same membranes (pleural thickening) may hint to the doctor that your lungs have been damaged by asbestos exposure without actually confirming that you have an asbestos-related disease. Other findings, namely a whitening of the lung tissue, are indicators of asbestosis.
The rate at which a case of interstitial lung disease will progress is unpredictable, but as it does, the affected lung tissue gets thicker, scars and leads to difficulty breathing. Some forms of ILD can be treated with medication (for inflammation), but to alleviate breathing problems oxygen is often required. Because interstitial lung disease is one of the causes of pleural effusion, treatment may also include thoracentesis to drain the excess fluid buildup associated with this condition. By working closely with your doctor, you should be able to determine which treatments are most appropriate for your case.
Because asbestosis and malignant mesothelioma are both caused by exposure to asbestos, some people develop both conditions. Like asbestosis, mesothelioma occurs when asbestos fibers subvert the lungs' filtration system and imbed themselves in the tissue of the lungs. What distinguishes mesothelioma from asbestosis is the growth of cancerous tumors. Mesothelioma is a lethal form of cancer that, once diagnosed, almost always worsens quickly and leads to death. Because there is no cure for the disease, mesothelioma treatment mostly focuses on relieving the pain and other unpleasant symptoms associated with mesothelioma.
There are three forms of mesothelioma:
- Pleural mesothelioma (mesothelioma of the membrane surrounding the lungs)
- Peritoneal mesothelioma (mesothelioma of the membrane surrounding the abdomen)
- Pericardial mesothelioma (mesothelioma of the membrane surrounding the heart)
Mesothelioma is further classified according to cell type. There are three types of mesothelial cells: epithelioid mesothelioma cells, sarcomatoid mesothelioma cells and biphasic mesothelioma cells.
For more information on mesothelioma cancer, visit our pages devoted to malignant mesothelioma. If you or a loved one has an asbestos-related disease, contact a mesothelioma attorney to learn more about your rights and the possibility of compensation.
[Page updated November 2011]