A 45-year-old coal miner with progressive dyspnea has chest X-ray showing upper lobe nodular opacities and fibrosis. Biopsy shows concentric collagen nodules with a necrotic core and doubly refractile silica particles. The diagnosis and mechanism of fibrosis is best described as:
- A Asbestosis; ferruginous body formation activating fibroblasts
- B Silicosis; silica activates NLRP3 inflammasome in macrophages, driving IL-1β-mediated fibrosis ✓
- C Berylliosis; T-cell-mediated granuloma formation
- D Coal workers' pneumoconiosis; carbonaceous particles causing lymphatic obstruction
Correct answer: B. Silicosis; silica activates NLRP3 inflammasome in macrophages, driving IL-1β-mediated fibrosis
Explanation
Silicosis is caused by crystalline silica particles that are phagocytosed by alveolar macrophages but resist lysosomal degradation. Lysosomal rupture activates the NLRP3 inflammasome, generating IL-1β and other pro-inflammatory cytokines that stimulate fibroblasts, producing the characteristic hyalinized collagen nodules. Asbestosis causes interstitial fibrosis with ferruginous (asbestos) bodies; berylliosis causes non-caseating granulomas; simple coal workers' pneumoconiosis causes carbon macules but without the nodular fibrosis of silicosis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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