Thyroid Disorders USMLE Step 1 Practice Question
A 41-year-old woman presents with a 3-month history of fatigue, constipation, weight gain, and cold intolerance. Vital signs show HR 52 bpm, BP 128/82 mmHg, temperature 36.2°C. Physical examination reveals dry skin, delayed relaxation of Achilles reflex, and no thyroid nodules. Laboratory studies demonstrate TSH 8.5 mIU/L (normal 0.4-4.0) and free T4 0.8 ng/dL (normal 0.8-1.8). She denies recent iodine supplement use. Which of the following is the most likely diagnosis?
Answer choices
- AHyperthyroidism due to Graves disease
- BEuthyroid sick syndrome
- CSecondary hypothyroidism
- DPrimary hypothyroidismCorrect answer
- ESubacute granulomatous thyroiditis
- FIatrogenic hypothyroidism from recent antithyroid medication use
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