As a result of asbestos exposure pleural plaques can develop. These are patches of fibrous thickening on the pleural membrane which can progress slowly and can calcify. The calcification makes pleural plaques very apparent on x-rays and they appear radiologically, generally at least 10 years after first exposure to asbestos with the extensiveness of plaqueing often related to duration and intensity of exposure. However, pleural plaques usually cause no measurable impairment of pulmonary function or of an individual’s general well-being. Many persons, often those who have only had brief exposure, develop pleural plaques. They are generally seen as a marker of past asbestos exposure but can in some instances cause chest pain and if extensive can restrict breathing capacity.
Pleural plaques are the most common form of asbestos disease. As with many asbestos diseases there is no effective treatment. Chest pain as a result of pleural plaques can be very severe and treatment may eventually involve narcotic analgesics. Chest pain can arise from various causes and the diagnosis of pleural plaque pain is a diagnosis of exclusion – other causes of the pain usually need to be excluded before plaques can be identified as the cause of pain. In addition pleural plaques can be very extensive and interfere or restrict the function of the lung causing breathlessness on exertion.
It is important to remember that pleural plaques are generally a marker of past asbestos exposure and usually do not cause symptoms and do not develop into a more serious asbestos disease. Pleural plaques are evidence of past asbestos exposure and it is the asbestos exposure itself that can cause more severe disease. Pleural plaques do not become malignant.
A pleural effusion may occur when the pleural becomes inflamed and fluid leaks into the space the visceral and parietal layers. Pleural effusion may cause chest pain and/or pleural thickening. A talc pleurodesis may be carried out to prevent further effusion which involves the insertion of talc or some other agent into the chest wall to adhere the parietal and visceral pleura, obliterating the pleural cavity and leaving no area for fluid to reaccumulate.
Asbestos related pleural disease is generally referred to as benign asbestos related pleural effusion. Symptoms include shortness of breath and discomfort. When the pleural fluid eventually goes away, the pleura on the lung may become thickened which can compress the lung.
Asbestos related pleural thickening is a fibrous layer of tissue covering a significant portion of the pleura. The thickening can lead to restrictive disease which prevents the lung from inflating completely when a patient takes a breath. Other causes of pleural thickening include pleural and chest infections, chest trauma, previous surgery and tuberculosis.
Pleural thickening is thought by some respiratory specialists to be caused by a pleural effusion which is the leakage of fluid into the space between the visceral and parietal pleura.