A Dictionary of Diseases
This section of the site provides a brief description of the range of medical conditions linked with asbestos exposure. The information for this section was complied by Clinical Professor Bill Musk, Department of Respiratory Medicine Sir Charles Gairdner Hospital, Perth, Western Australia.
This is thickening of the lining of the chest wall and is frequently observed in people who have worked with asbestos. It is often considered to be an indicator of asbestos exposure. It rarely interferes with the function of the lungs. It is not malignant and does not lead to the development of malignant mesothelioma or lung cancer. No treatment is necessary.
Occasionally people with past asbestos exposure develop fluid in the pleural cavity (between the lung and the chest wall) which is not due to cancer. It may result in permanent and sometimes progressive pleural thickening which, when severe, may interfere with the expansion of the lungs. It may require draining the fluid from the lungs, which is done in hospital. It is not malignant and does not lead to cancer.
This is a form of pneumoconiosis or dust disease of the lung caused by asbestos. The usual time from first exposure to first clinical signs of asbestosis is 10 to 20 years. Asbestosis is an inflammatory reaction in the lungs brought about by inhaled asbestos fibres. Inflammation occurs throughout the tissues of the lungs and leads to scarring (fibrosis). This process results in stiffening of the lung tissues, which makes the work of breathing harder, and impairment of the uptake of oxygen from the air into the blood. The main symptom of asbestosis is breathlessness on exertion. The diagnosis is made from a history of asbestos exposure, the presence of crackling noises in the chest heard with a stethoscope, the presence of abnormal shadowing on the chest x-ray and abnormalities of lung function tests. There is no treatment for asbestosis. Asbestosis tends to progress with the passage of time.
Lung cancer is a malignant tumour found within the lungs. Lung cancer caused by asbestos exposure can take 20 years or more from the time of exposure before the first clinical signs appear. The types of lung cancer that results from asbestos exposure are the same as those which are caused by smoking. Treatmeant is the same: surgery in suitable cases, radiotherapy or chemotherapy. Exposure to asbestos increases the risk of developing lung cancer, especially in people who have smoked cigarettes. The risk of developing lung cancer in people who have been exposed to asbestos is reduced if they stop smoking.
Malignant pleural mesothelioma is a cancer arising from the cells covering the surface of the lung and lining the chest wall. Malignant peritoneal mesothelioma is a similar cancer arising from the surface covering of the bowel or the lining of the abdominal cavity (stomach). Mesothelioma is a rare form of cancer. Usually the chances of getting this disease are one to two in a million per year. This disease seems to occur after less exposure to asbestos dust than do other asbestos related diseases, and may take up to 40 years or more to show itself after first exposure. It is thought to be caused by the body’s reaction to the needle like fibres of asbestos piercing the lining of the lung or abdomen.
Malignant mesothelioma frequently results in the accumulation of large amounts of fluid in the chest or abdominal cavities. This tends to cause breathlessness or distension of the abdomen. The cancer cells also tend to invade the normal tissues of the lung and chest wall. In the chest wall this causes chest pain which may be severe.