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Pleural plaque disease is a type of lung disease which can develop in the lungs of people who have been chronically exposed to airborne asbestos fibers. Asbestos is a naturally occurring mineral which was used widely in the twentieth century, particularly in construction, textile manufacturing, and ship-building. Asbestos is potentially toxic when inhaled, and can cause a type of lung cancer called mesothelioma, and a chronic lung disease called asbestosis. Pleural plaques may develop as a symptom of asbestosis, but may also form in the absence of any other type of lung disease.
Although most uses of asbestos have been discontinued in many countries, asbestos is still mined in several locations, including Australia, Canada, Finland, North America, and South Africa. In addition, asbestos lung disease may remain undetected for two decades or more in an affected person. This means pleural plaque disease, and other asbestos diseases, are still a significant issue in many parts of the world.
Asbestos fibers are long, thin, and extremely durable. The most dangerous fibers are tiny, and are too small to be seen with the naked eye. When these fibers are inhaled into the lungs, they lodge in lung tissue. The body is not able to remove the fibers from the lungs, or break them down into a less harmful form. Over a period of up to four decades, these fibers cause chronic irritation in lung tissue. This leads to the deposition of collagen fibers around locations where asbestos is located, forming a pleural plaque.
Eventually, the pleural plaque may become calcified, which means calcium salts have built up in the tissue, causing it to harden. The area where a pleural plaque is located therefore cannot function as normal lung tissue does, because it has hardened and can no longer expand as the lungs inflate during breathing. People with pleural plaques have difficulty breathing during exertion; in advanced cases of disease, they may have difficulty breathing even when at rest. Breathing may also be painful. Another common symptom of pleural plaque disease is the presence of pleural effusion, which occurs because fluid builds up in the pleural cavity. This is the body cavity where the lungs are located.
A person with pleural plaques cannot be cured; once the plaques are present in the lungs, they cannot be removed or repaired. Further damage can be prevented if he or she is no longer exposed to asbestos. Since the disease cannot be cured, treatment focuses on managing symptoms. One of the most common treatments is the use of an oxygen mask for people who have difficulty breathing.
Pleural effusion is treated with a procedure called aspiration, in which a long thin needle is inserted into the pleural cavity. Excess fluid is removed through the needle. A procedure called pleurodesis may be performed for people with severe, recurrent pleural effusion. During this procedure, fluid is drained from the pleural cavity, and surgical talc or another inflammatory substance is introduced into the cavity. The resulting inflammation causes swelling that closes up the layers of the pleural membrane which surrounds the lungs, preventing fluid from building up.
People with pleural plaques are also advised to give up smoking as soon as possible, if applicable. In addition, it is important that respiratory infections, even minor infections such as a cold, are treated promptly and monitored carefully. Due to decreased lung function, such infections can become serious if not treated.