Unlike asbestosis, pleural plaques may occur in individuals with peripheral exposure such as working in a shipyard for one or two years during World War II, living next to an asbestos mine, or employment as an electrician, welder, or plumber. Generally single or even multiple plaques are not a cause of symptoms or clinically significant physiologic abnormalities. The chest roentgenogram is distinctive and shows plaques along the lateral pleural surfaces, diaphragmatic surfaces, or along the mediastinal or pericardial surfaces. This disorder has declined during the past 50 years in the United States due to the control of dust levels and improvement of mining techniques but has not been eliminated. Chronic cough is the most common symptom.
Dyspnea occurs later.
Physiologic findings may include airflow obstruction early and decreased diffusing capacity in late stages. Radiographic findings remain the hallmark of this disorder, with small rounded opacities early and large opacities of progressive massive fibrosis in the late stage. In addition, the typical nodular opacities may disappear as the massive fibrosis progresses. Such patients should also be monitored for tuberculosis. A small group of stone masons cutting and shaping hard sandstone to replace the tracery in the in the windows of a ruined medieval cathedral were exposed to levels of respirable quartz up to 130 times the workplace standard over a period of up to 6 years.