PA25.5 | Occupational & Interstitial Lung Disease — Summary & Reflection

REFLECT

Consider this: A 45-year-old construction worker comes to your outpatient clinic in Chennai complaining of worsening breathlessness over 3 years. He has been demolishing old buildings for 20 years. CXR shows bilateral pleural plaques and basal interstitial opacities.

1. What is your primary pathological diagnosis, and what specific histological finding would you expect on biopsy?
2. What are the two malignant complications you must counsel him about?
3. His wife asks whether their teenage son — who sometimes visited the work site — is also at risk. What do you tell her?
4. If spirometry is available, what pattern do you predict, and what will FEV1/FVC ratio show?

Write a 150-word answer integrating the pathological basis with the clinical management principles.

KEY TAKEAWAYS

Module summary — Occupational & Interstitial Lung Disease:

• Restrictive lung disease: stiff lungs, ↓TLC, ↓FVC, normal/↑FEV1/FVC — end-point of all diffuse fibroses.

• Pneumoconiosis: lung reaction to inhaled mineral dust; determinants = particle size (1–5 µm hits alveoli), dose, solubility, host factors; all activate macrophages → fibrogenic cytokines → collagen.

• CWP: carbon dust; anthracosis → macules → PMF; Caplan syndrome with RA; no major cancer risk.

• Silicosis: silica/quartz; whorled hyalinised silicotic nodules, birefringent particles; eggshell calcification; ↑TB (silicotuberculosis); IARC Group 1 carcinogen.

• Asbestosis: asbestos fibres; lower-lobe diffuse fibrosis; asbestos/ferruginous bodies; pleural plaques; 1000× ↑ mesothelioma; synergistic with smoking for bronchogenic Ca.

• HP: organic antigens (Farmer's, Bird-fancier's lung); poorly-formed bronchiolocentric granulomas; reversible if exposure removed.

• IPF/UIP: fibroblastic foci, temporal heterogeneity, basal sub-pleural honeycombing; poor prognosis.

• Sarcoidosis: non-caseating well-formed perilymphatic granulomas; bilateral hilar adenopathy; ↑ACE; mostly self-limiting.

• Shared complications: pulmonary hypertension → cor pulmonale → death; ↑ infection (TB in silicosis); type I respiratory failure.