A 50-year-old man who worked as a sandblaster for 20 years has progressive exertional dyspnoea. Chest radiograph shows small rounded opacities predominantly in the upper zones with eggshell calcification of hilar lymph nodes. Compared with asbestosis, which statement correctly distinguishes his condition?
- A It affects the lower zones and predisposes to mesothelioma
- B It characteristically spares the hilar lymph nodes
- C It produces ferruginous bodies on lung biopsy
- D It affects the upper zones and markedly increases susceptibility to tuberculosis ✓
Explanation
Silicosis from free crystalline silica exposure causes upper-zone nodular fibrosis with pathognomonic eggshell calcification of hilar nodes, and silica impairs macrophage function so silicotics have a several-fold increased risk of tuberculosis, including rapid progression. Asbestosis, by contrast, is lower-zone predominant, produces pleural plaques, carries risk of bronchogenic carcinoma and mesothelioma, and shows asbestos bodies (ferruginous bodies) on histology. Option C describes asbestosis, option A describes asbestosis, and option B is false since node calcification is characteristic of silicosis.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
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