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CM11.1-6 | Occupational Health — Practice Quiz
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A 48-year-old sandblaster presents with progressive dyspnoea and a dry cough for 3 years. His chest X-ray shows bilateral upper-zone nodular opacities with 'eggshell calcification' of hilar lymph nodes. What is the most likely diagnosis?
Correct. Silicosis produces bilateral upper-zone nodular opacities and the pathognomonic 'eggshell' calcification of hilar lymph nodes due to crystalline silica deposition. Sandblasting is a classic high-risk occupation.
Silicosis hallmarks: upper-zone nodules, eggshell hilar calcification, accelerated TB risk (silicotuberculosis). Compare: asbestosis → lower lobe honeycombing + pleural plaques; byssinosis → chest tightness worst on Mondays (re-exposure pattern).
Incorrect. Eggshell calcification of hilar nodes is pathognomonic for silicosis, not asbestosis (lower-zone fibrosis + pleural plaques), byssinosis (reversible airway obstruction), or farmer's lung (hypersensitivity pneumonitis).
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A 36-year-old woman working in a textile mill complains of chest tightness that is worst every Monday morning but improves by Thursday. She has no symptoms on Sundays. Which occupational lung disease does this pattern suggest?
Correct. Byssinosis (cotton/hemp/flax dust disease) produces the classic 'Monday chest' — airway obstruction worst on the first day of re-exposure after weekend rest, due to bronchoconstriction from bract dust endotoxins. It improves as the week progresses (tachyphylaxis).
Byssinosis: Cotton/hemp/flax dust → grade 1/2 airflow obstruction, worst on Mondays, improves midweek (tachyphylaxis). Prevention: dust suppression, wet-spinning. Park's textbook uses this Monday pattern as the defining clinical feature.
Incorrect. The Monday-worst, week-end-better temporal pattern is the diagnostic hallmark of byssinosis from cotton dust, not the other pneumoconioses.
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A 29-year-old automobile battery factory worker presents with fatigue, abdominal colic, and peripheral neuropathy (wrist-drop). His peripheral blood smear shows microcytic hypochromic anaemia with basophilic stippling of red cells. Which heavy-metal is most likely responsible?
Correct. Lead inhibits ALA dehydratase and ferrochelatase in haem synthesis, causing microcytic anaemia with basophilic stippling. Clinical triad: abdominal colic (saturnine colic), peripheral motor neuropathy (extensor wrist-drop), and anaemia. Burton's blue gum line may be present.
Lead toxicity: inhibits δ-ALA dehydratase → basophilic stippling + microcytic anaemia; wrist-drop (extensor neuropathy); Burton's line (blue-black gum margin); BPb >10 µg/dL is actionable. Treatment: DMSA (succimer) for children; CaNa2EDTA for adults with high BPb.
Incorrect. Basophilic stippling + wrist-drop + saturnine colic is the classic triad of chronic lead toxicity, not mercury or arsenic poisoning.
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Under the Employees' State Insurance Act 1948, what is the current monthly wage ceiling (in rupees) above which an employee is NOT covered under the ESI scheme?
Correct. The ESI wage ceiling was revised to ₹21,000/month in 2017. Employees earning above this threshold are not compulsorily covered; those earning ₹21,000/month or less are mandatorily covered.
ESI Act 1948: Tripartite contribution — employer 3.25% + employee 0.75% = 4% of wages. Wage ceiling ₹21,000/month (2017). Benefits include sickness benefit (70% wages × 91 days), maternity benefit (100% × 26 weeks), disablement benefit, dependent's benefit, medical benefit. Applicable to non-seasonal factories employing ≥10 workers.
Incorrect. The current ESI wage ceiling is ₹21,000/month (revised 2017). ₹15,000 was the older ceiling; ₹10,000 and ₹25,000 are not the mandated thresholds.
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A garment factory worker earning ₹18,000/month falls ill and is medically certified unfit for work. Under the ESI Act, what is the maximum duration of sickness benefit payable to this worker in a benefit period?
Correct. Under ESI Act Section 46, the ordinary sickness benefit is payable for a maximum of 91 days in two consecutive benefit periods. The cash benefit is 70% of the employee's average daily wages.
ESI Sickness Benefits: Ordinary sickness benefit = 91 days per 2 consecutive benefit periods at 70% wages. Extended sickness benefit (for 34 specified serious diseases including TB, cancer) = up to 730 days at 80% wages. Enhanced sickness benefit for sterilisation = 14 days (male) / 7 weeks (female) at 100% wages.
Incorrect. Ordinary sickness benefit under ESI Act is 91 days per benefit period. Extended sickness benefit (for 34 specific long-term diseases) can extend up to 2 years.
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Under the Factories Act 1948, in which of the following factories is the appointment of a Safety Officer mandatory?
Correct. Section 40-B of the Factories Act 1948 mandates appointment of a Safety Officer in factories employing 1,000 or more workers. For factories with hazardous processes (Schedule I) employing 500+ workers, a Safety Officer is also required.
Factories Act 1948 key thresholds: ≥10 workers (with power) = factory; ≥20 workers (without power) = factory; ≥250 workers = canteen mandatory; ≥500 workers (hazardous) = Safety Officer; ≥1,000 workers (any) = Safety Officer; occupational health centre (OHC) required per state rules. Welfare Officer: ≥500 workers.
Incorrect. A Safety Officer is mandatory for factories with ≥1,000 workers (general) or ≥500 workers in hazardous processes (Schedule I). The canteen provision kicks in at ≥250 workers.
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A data entry operator develops pain and paraesthesia in her wrist and first three fingers after 8 hours of keyboard use daily for 6 months. Clinical examination reveals positive Phalen's test and Tinel's sign at the wrist. Which work-related disorder does she most likely have?
Correct. Carpal tunnel syndrome (CTS) is the most common work-related upper limb disorder. Repetitive wrist flexion/extension during keyboard use compresses the median nerve in the carpal tunnel, causing pain, numbness, and paraesthesia in the thumb, index, middle, and radial half of ring finger. Phalen's test and Tinel's sign are classic.
Ergonomic WRULDs: CTS (repetitive wrist flexion, median nerve) — Phalen's + Tinel's; De Quervain's (pinch/twist, APL+EPB tendons) — Finkelstein's test; Lateral epicondylitis (pronation/supination) — resisted wrist extension. Prevention: ergonomic keyboard height, wrist rests, micro-breaks every 30 min.
Incorrect. Positive Phalen's + Tinel's at the wrist + first 3 fingers = median nerve compression = carpal tunnel syndrome. De Quervain's involves the radial styloid; lateral epicondylitis involves the elbow.
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A junior resident doctor sustains a needlestick injury from an HIV-positive patient (viral load detectable). The needle was a hollow bore used for phlebotomy from a peripheral vein. What is the recommended HIV post-exposure prophylaxis (PEP) regimen for this resident?
Correct. Current NACO/WHO guidelines recommend a preferred 3-drug PEP regimen: Tenofovir (TDF) + Emtricitabine (FTC) + Dolutegravir (DTG) for 28 days. This must be initiated within 72 hours of exposure (ideally within 1-2 hours) for maximum efficacy.
HIV PEP: Preferred = TDF 300mg + FTC 200mg + DTG 50mg once daily × 28 days. Start within 72 hours (earlier = better). Risk for hollow-bore percutaneous: ~0.3%. Baseline HIV test + 6-week + 12-week follow-up. Report to Infection Control. Also assess HBV (give HBIG + vaccine if non-immune) and HCV status.
Incorrect. The current preferred HIV PEP regimen is TDF + FTC + DTG for 28 days. Two-drug regimens are no longer recommended as preferred; monotherapy is obsolete; 14 days is insufficient.
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CLINICAL SCENARIO
You are the Factory Medical Officer at a textile mill employing 800 workers. On a routine Monday morning clinic, 12 workers present with chest tightness and dry cough. All work in the carding section (opening and cleaning raw cotton). Their symptoms started 2 hours after entering the mill and improve after they leave. A similar pattern occurred last Monday. Lung function tests show reduced FEV1/FVC ratio that partially reverts by end of shift.
Answer the following questions based on the scenario above.
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Based on the temporal pattern (Monday morning, carding section, reversible obstruction), what is the most likely occupational diagnosis?
Correct. The classic Monday-chest pattern with reversible airflow obstruction in carding section workers = byssinosis. Cotton bract dust endotoxins cause bronchoconstriction via non-immune mechanisms.
Incorrect. The combination of carding section + reversible obstruction + Monday pattern is diagnostic for byssinosis.
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As the Factory Medical Officer, what is the MOST effective primary preventive measure you should implement to reduce new cases of byssinosis in this mill?
Correct. The hierarchy of controls prioritises engineering controls over personal protective equipment (PPE). Local exhaust ventilation + wet-spinning (wetting raw cotton to suppress dust) directly reduces airborne cotton bract dust at the source — the highest level of primary prevention.
Incorrect. Per the hierarchy of controls, engineering controls (source reduction via LEV + wet-spinning) rank above PPE (respirators) or administrative controls (rotation). Bronchodilators treat disease, not prevent exposure.
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A retired shipyard insulation worker presents with progressive dyspnoea, clubbing, and fine basal crackles. Chest X-ray shows bilateral lower-zone fibrosis and calcified pleural plaques. The most characteristic pleural finding confirming asbestos exposure is:
Correct. Bilateral calcified pleural plaques, particularly on the diaphragmatic and posterolateral chest wall surfaces, are the radiological hallmark of asbestos exposure. They may appear 20–40 years after first exposure (long latency).
Asbestosis: lower-zone fibrosis + bilateral calcified pleural plaques (diaphragmatic) + mesothelioma risk + latency 20–40 years. Fibre types: amphiboles (crocidolite, amosite) more carcinogenic than chrysotile. Mesothelioma: no safe level of asbestos exposure. Compare: silicosis = upper-zone nodules + eggshell hilar calcification.
Incorrect. Bilateral calcified diaphragmatic pleural plaques are pathognomonic of past asbestos exposure. Silicosis causes upper-zone nodules with eggshell calcification, not pleural plaques.
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