Which disease is most classically linked to inhalation of crystalline silica?

• A. Asbestosis
• B. Coal Workers' Pneumoconiosis
• C. Silicosis
• D. Hypersensitivity Pneumonitis

Answer: (C)

Inhalation of crystalline silica most classically causes silicosis, a fibrotic pneumoconiosis. Silica particles are ingested by alveolar macrophages, triggering macrophage death and a cascade of inflammatory and fibrotic signaling. This leads to nodular fibrotic lesions, typically in the upper lobes, and can progress to progressive massive fibrosis. The condition also impairs macrophage function, increasing susceptibility to tuberculosis. Exposure is common in mining, stone cutting, sandblasting, and glass-making.

Asbestosis is linked to asbestos exposure and shows lower-lobe predominant interstitial fibrosis with pleural plaques. Coal workers’ pneumoconiosis arises from coal dust with simple nodules that may progress to fibrosis. Hypersensitivity pneumonitis results from immune reactions to inhaled organic antigens and has a different radiographic and clinical pattern. Thus, the classic association with crystalline silica is silicosis.