A 61-year-old retired shipyard worker has progressive exertional dyspnoea over 4 years. Chest X-ray shows calcified pleural plaques along both hemidiaphragms and lateral chest walls, with small linear lower-zone opacities. Pulmonary function testing shows a restrictive defect with reduced DLCO. Which statement about this condition is correct?
- A Lower-zone interstitial fibrosis begins 15 to 20 years after first exposure to the causative fibre ✓
- B It produces predominantly upper-zone fibrosis with eggshell calcification of hilar nodes
- C Pleural plaques themselves significantly restrict lung function
- D It carries no increased risk of bronchogenic carcinoma
Correct answer: A. Lower-zone interstitial fibrosis begins 15 to 20 years after first exposure to the causative fibre
Explanation
Asbestosis is diffuse interstitial fibrosis with a long latency of roughly 15 to 20 years or more after first exposure, radiologically lower-zone predominant, accompanied by calcified pleural plaques marking exposure. Silicosis, by contrast, causes upper-zone fibrosis with eggshell hilar calcification. Pleural plaques are markers of exposure and cause little functional impairment by themselves. Asbestos exposure multiplies lung cancer risk, especially in smokers, and increases mesothelioma risk.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
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Written and medically reviewed by the StethoPrep medical team.