Pituitary Disorders USMLE Step 1 Practice Question
A 67-year-old man with treated hypothyroidism on levothyroxine 100 mcg daily presents with severe frontal headache, confusion, and bradycardia. Vital signs: BP 88/56, HR 48, RR 12, Temp 35.8°C. Exam reveals myxedema facies, delayed reflexes, and no focal neurologic deficits. Laboratory studies show TSH 0.2 mIU/L, free T4 0.3 ng/dL, and hyponatremia (Na 118 mEq/L). MRI brain demonstrates a sellar mass. Which diagnosis best explains these findings?
Answer choices
- ALevothyroxine-induced thyroid storm
- BSick euthyroid syndrome with suppressed TSH and T4
- CAcute myxedema coma from primary hypothyroidism
- DPrimary hypothyroidism with elevated TSH levels
- ECentral hypothyroidism from inadequate levothyroxine dosing of the pituitary glandCorrect answer
- FSecondary hypothyroidism from pituitary apoplexy with acute TSH deficiency
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