Thyroid Disorders USMLE Step 1 Practice Question
A 58-year-old man with a history of papillary thyroid cancer treated with total thyroidectomy 5 years ago is on levothyroxine suppression therapy. His current free T4 is 1.9 ng/dL (high-normal) and TSH is 0.05 mIU/L (suppressed). He now presents with new-onset atrial fibrillation and osteoporosis on DEXA scan. Which of the following best describes the relationship between his current management and these complications?
Answer choices
- AChronic TSH suppression with supraphysiologic free T4 increases risk of atrial fibrillation and accelerates bone lossCorrect answer
- BLevothyroxine monotherapy is insufficient; combination with T3 is needed
- CPost-thyroidectomy hypothyroidism causes cardiac arrhythmias and bone disease
- DPapillary thyroid cancer has metastasized to the heart and bones
- EAge-related cardiovascular and skeletal changes unrelated to thyroid hormone levels
- FExcessive iodine intake from the levothyroxine formulation causes thyroiditis with release of stored thyroid hormones leading to atrial fibrillation and secondary hyperparathyroidism
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