Diffuse pleural thickening and circumscribed pleural plaques are two nonmalignant pleural diseases caused by asbestos exposure. It has generally been accepted that diffuse pleural thickening is associated with measurable pulmonary impairment and clinical symptoms; however, the functional impact of asbestos-induced pleural plaques still remains controversial. Recent literature suggests that asbestos-induced pleural plaques are associated with ventilatory impairment and respiratory symptoms. We critically analyzed the literature from 1965 to 1999 evaluating this potential relationship. We conclude that: (1) individuals with asbestos-induced pleural plaques may have alterations in pulmonary function and/or clinical symptoms that are independent of smoking and radiographic parenchymal fibrosis; and (2) the respiratory changes due to asbestos-induced pleural plaques are generally less severe than those caused by diffuse pleural thickening. The mechanism of the pulmonary functional changes associated with pleural plaques has not been elucidated.
*Department of Radiology, George Washington University Medical Center, Washington, D.C.USA, and the †Division of Pulmonary and Critical Care Medicine, University of California at San Diego, La Jolla, CA.
Editorial Comment: Whether or not Pleural plaques cause significant pulmonary function impairment and/or clinical symptoms remains controversial. Currently, an international panel of experts is being assembled to reach consensus on a variety of asbestos-related disease issues, including the topic addressed by this report. In spite of the controversial nature of this subject, the editorial board decided to publish this provocative review.
Address correspondence to: Lewis J. Rubin, MD, Division of Pulmonary and Critical Care Medicine, University of California at San Diego, 9300 Campus Point Drive, La Jolla, CA 92037.