Thyroid Disorders USMLE Step 1 Practice Question
A 28-year-old woman presents with progressive weight loss despite increased appetite, heat intolerance, anxiety, and palpitations for 6 weeks. Vital signs show BP 148/82 mmHg, HR 112/min, RR 18/min, temperature 37.8°C. Physical examination reveals diffuse nontender goiter, fine tremor, and bilateral exophthalmos. TSH is suppressed at 0.02 mIU/L with elevated free T4 at 18 ng/dL. Thyroid peroxidase antibodies are negative. Which of the following best describes the pathophysiologic mechanism of her disease?
Answer choices
- AAutoantibodies against thyroid peroxidase
- BIodine deficiency causing increased TSH
- CDestruction of the thyroid by granulomatous inflammation
- DMutation activating RET in parafollicular cells
- EAutoantibodies stimulating the TSH receptorCorrect answer
- FSomatic TSH receptor mutation causing autonomous thyroid function
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