Diabetes Mellitus USMLE Step 1 Practice Question
A 24 year old man develops severe polyuria and polydipsia 3 days after transsphenoidal surgery for a pituitary adenoma. Serum sodium is 152 mEq/L and urine osmolality is low. Administration of desmopressin markedly increases urine osmolality. Which of the following is the most likely cause of his water balance disorder?
Answer choices
- AInadequate secretion of ADHCorrect answer
- BOsmotic diuresis due to hyperglycemia
- CCollecting duct resistance to ADH
- DIncreased renal sensitivity to aldosterone
- EExcess secretion of atrial natriuretic peptide
- FDiabetes mellitus type 1 resulting from pancreatic beta cell destruction
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.