Thyroid Disorders USMLE Step 1 Practice Question
A 45-year-old woman presents with progressive fatigue, weight gain of 8 kg over 3 months, constipation, and cold intolerance. Vital signs show BP 128/82 mmHg, HR 58 bpm, RR 14/min, temperature 36.2°C. Examination reveals a painless, firm, diffusely enlarged thyroid gland without nodules. Laboratory studies demonstrate TSH 12.5 mIU/L (elevated), free T4 0.6 ng/dL (low), and positive anti-thyroid peroxidase antibodies. Thyroid ultrasound shows homogeneous echotexture. She denies recent iodine exposure. Which of the following is the most likely diagnosis?
Answer choices
- AMedullary thyroid carcinoma
- BToxic multinodular goiter
- CHashimoto thyroiditisCorrect answer
- DSubacute granulomatous thyroiditis
- EGraves disease
- FCentral hypothyroidism due to pituitary adenoma
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