Asbestos Related Pleural Disease

Asbestos is a naturally occurring, fibrous silicate that was widely used in the past for commercial applications because of its heat-resistance properties. Asbestos exists in several forms. The 2 primary groups of asbestos are made up of amphibole and serpentine fibers. Amphibole fibers, which are characteristically straight, rigid, and needlelike, can be subdivided into commercial amphiboles (crocidolite, blue asbestos, and amosite [brown asbestos]) and noncommercial amphiboles (actinolite, anthophyllite, and tremolite). Chrysotile (white asbestos) is the only form of serpentine asbestos that is used commercially, and it accounts for more than 90% of asbestos used in the United State.

For the most part, asbestos exposure has been industrial or occupational; such exposure primarily affects workers involved in mining or processing asbestos or those involved in the use of asbestos in the shipbuilding, construction, and textile- and insulation-manufacturing industries. Chrysotile is mined in Canada, and tremolite and anthophyllite are mined in Finland and North America. Crocidolite and amosite are mined in South Africa and Australia. About 2-6 million people in the United States are estimated to have had significant levels of exposure.

High exposures ceased in the United States in the late 1970s, and later in the United Kingdom, because of governmental legislation passed after the adverse effects became recognized. However, because the latency period between an initial exposure and the development of most asbestos-related disease is 20 years or longer, asbestos-related disease remains an important public health issue.

The spectrum of ASBESTOS-RELATED thoracic DISEASES includes benign PLEURAL effusion, PLEURAL plaques, diffuse PLEURAL thickening, rounded atelectasis, asbestosis, mesothelioma, and lung cancer.

Asbestosis is defined as diffuse lung fibrosis due to the inhalation of asbestos fibers, and it is one of the major causes of occupationally related lung damage. Mesothelioma is a malignant pleural or peritoneal tumor that rarely occurs in patients who have not been exposed to asbestos.

The diagnostic approach to asbestos-related intrathoracic disease is different from that of other diffuse lung diseases because of the medicolegal implications. The likelihood of asbestos-related disease should be determined, and other possible causes should be eliminated. An assessment of the extent of disease is used to calculate compensation. Therefore, imaging plays a pivotal role in the diagnosis and management of asbestos-related disease.