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Many acute and chronic pulmonary diseases are directly related to inhalation of noxious substances encountered in the workplace. Disorders that are linked to occupational exposures may be classified as follows: (1) pneumoconioses, (2) hypersensitivity pneumonitis, (3) obstructive airway disorders, (4) toxic lung injury, (5) lung cancer, (6) pleural diseases, and (7) other occupational pulmonary diseases.
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Pneumoconioses are chronic fibrotic lung diseases caused by the inhalation of inert inorganic dusts. Pneumoconioses range from asymptomatic disorders with diffuse nodular opacities on chest radiograph to severe, symptomatic, life-shortening disorders. Clinically important pneumoconioses include coal worker’s pneumoconiosis, silicosis, and asbestosis (Table 9–20). Treatment for each is supportive; pulmonary rehabilitation may be considered.
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A. Coal Worker’s Pneumoconiosis
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In coal worker’s pneumoconiosis, ingestion of inhaled coal dust by alveolar macrophages leads to the formation of coal macules, usually 2–5 mm in diameter, that appear on chest radiograph as diffuse small opacities that are especially prominent in the upper lung. Simple coal worker’s pneumoconiosis is usually asymptomatic; abnormalities of PFTs are unimpressive. In complicated coal worker’s pneumoconiosis (“progressive massive fibrosis”), conglomeration and contraction in the upper lung zones occur, with radiographic features resembling complicated silicosis. Caplan syndrome is a rare condition characterized by the presence of necrobiotic rheumatoid nodules (1–5 cm in diameter) in the periphery of the lung in coal workers with rheumatoid arthritis.
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In silicosis, extensive or prolonged inhalation of free silica (silicon dioxide) particles (sandblasters, foundry, granite and stone cutting, molding, ceramics) in the respirable range (0.3–5 mcm) causes the formation of small rounded opacities (silicotic nodules) throughout the lung. Calcification of the periphery of hilar lymph nodes (“eggshell” calcification) is an unusual radiographic finding that strongly suggests silicosis. Simple silicosis is usually asymptomatic and has no effect on routine PFTs; in complicated silicosis, large conglomerate densities appear in the upper lung and are accompanied by dyspnea and obstructive and restrictive pulmonary dysfunction. The incidence of pulmonary tuberculosis is increased in patients with silicosis. All patients with silicosis should have a tuberculin skin test and a chest radiograph to rule out tuberculosis.
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Asbestosis is a nodular interstitial fibrosis occurring in workers exposed to asbestos fibers (shipyard and construction ...