A worker develops progressive massive fibrosis (PMF) with bilateral upper-lobe opacities on chest X-ray after 15 years in a coal mine. Which occupational disease does this represent, and what is the minimum silica content needed in coal dust to cause this condition?
- A Coalworker's pneumoconiosis (CWP); free silica content >10% causes accelerated CWP ✓
- B Silicosis from pure silica; silica content >100% of dust
- C Byssinosis; cotton dust endotoxin content exceeds safety threshold
- D Asbestosis; anthophyllite asbestos in coal dust
Correct answer: A. Coalworker's pneumoconiosis (CWP); free silica content >10% causes accelerated CWP
Explanation
Coalworker's pneumoconiosis (CWP) is caused by inhalation of mixed coal dust; when free (crystalline) silica content in the dust exceeds 10%, progressive massive fibrosis (PMF) is more likely and the disease behaves more like silicosis. PMF (conglomerate shadows > 1 cm) represents the complicated form of CWP, causing severe restriction and cor pulmonale. Silicotuberculosis is a major complication. CWP is a notifiable industrial disease under the Mines Act 1952 and the Workmen's Compensation Act.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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