Thyroid Disorders USMLE Step 1 Practice Question
A 52-year-old man presents to his primary care physician with a 3-month history of progressive fatigue, weight gain of 8 kg, and cold intolerance. He denies palpitations, anxiety, or heat intolerance. Physical examination reveals bradycardia (heart rate 58 bpm), dry skin, delayed relaxation phase of deep tendon reflexes, and a firm, non-tender thyroid gland without nodules. Laboratory studies show: TSH: 18 mIU/L (normal 0.5–5.0)
Free T4: 0.8 ng/dL (normal 0.8–1.8)
Thyroid peroxidase (TPO) antibodies: Negative
Thyroglobulin antibodies: Negative Which of the following is the most appropriate initial management?
Answer choices
- ALevothyroxine 75–100 mcg daily with TSH rechecked in 6–8 weeks
- BLevothyroxine 25–50 mcg daily with TSH rechecked in 6–8 weeksCorrect answer
- CLevothyroxine plus liothyronine (T3) combination therapy to provide both thyroid hormones
- DObservation for 3 months without pharmacologic intervention, given borderline low-normal free T4
- EPropranolol 40 mg twice daily to manage bradycardia and constitutional symptoms
- FReferral to endocrinology for thyroid biopsy to exclude malignancy
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