Thyroid Disorders USMLE Step 1 Practice Question
A 51-year-old woman presents with a 2-week history of severe anxiety, palpitations, and tremor. She was started on amiodarone for atrial fibrillation 2 weeks ago. Vital signs show HR 108 bpm, BP 142/88 mmHg, RR 18, temperature 37.2°C. Laboratory studies reveal TSH 0.2 mIU/L (normal 0.4–4.0), free T4 2.1 ng/dL, and free T3 3.1 pg/mL. She denies recent weight loss. Which of the following best explains her presentation?
Answer choices
- AGraves' disease triggered by amiodarone exposure
- BAtrial fibrillation breakthrough with inadequate rate control
- CAmiodarone-induced hypothyroidism from iodine excess
- DDrug-induced lupus with thyroid involvement
- EAmiodarone-induced type I thyroiditis with thyroid hormone releaseCorrect answer
- FAmiodarone-induced type II thyroiditis with increased cellular metabolism
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