A 42-year-old stone quarry worker presents with progressive exertional dyspnoea and bilateral upper-lobe nodular opacities on chest X-ray. He had 18 years of exposure to crystalline silica dust. His condition represents which stage on the ILO 2011 international classification of occupational radiographs?

• A Category 0 — normal; other diagnosis should be sought
• B Category 1 — small opacities present, profusion slightly above baseline
• C Category 2/3 — moderate-to-severe profusion of small opacities consistent with silicosis
• D Progressive Massive Fibrosis (PMF) which is classified separately as large opacity category A/B/C ✓

Explanation

With 18 years of heavy silica exposure and bilateral upper-lobe nodular opacities that are likely large (>1 cm given the clinical picture of severe dyspnoea), this presentation is consistent with Progressive Massive Fibrosis (PMF), classified under ILO as large opacities (categories A — aggregate diameter 1–5 cm, B — >5 cm in upper zone, C — >5 cm in middle zone). The small opacity categories 1, 2, and 3 describe early and moderate silicosis without large coalescent nodules. PMF carries significantly worse prognosis and distinguishes advanced silicosis from early disease.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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