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Hypothyroidism — USMLE Step 2 CK MCQ

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HardInternal MedicineHypothyroidismUSMLE Step 2 CK

A 72-year-old with stable coronary artery disease has fatigue, constipation, TSH 28 mIU/L, and low free thyroxine. He is clinically stable and has no myxedema features. Which initial levothyroxine strategy is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Begin levothyroxine 12.5–25 micrograms daily and titrate gradually

Explanation lettering: E = shown as A · A = shown as B · B = shown as E

E is correct: known coronary disease requires a low levothyroxine starting dose, usually 12.5–25 micrograms daily, followed by gradual titration with TSH and angina monitoring because a rapid metabolic increase can provoke ischemia or arrhythmia. A is suitable for many younger healthy adults but is too aggressive here. B is reserved for myxedema coma. C produces unstable T3 peaks and is not routine replacement. D leaves overt hypothyroidism untreated without justification.

Reference: AACE/ATA clinical practice guideline for hypothyroidism in adults. https://www.thyroid.org/thyroidguidelines/file/thy.2012.0205.pdf