Diabetes Mellitus USMLE Step 1 Practice Question
A 28-year-old woman with chronic anxiety drinks more than 8 liters of water per day. She has frequent urination. Serum sodium is 129 mEq/L and serum osmolality is low. During water deprivation, urine osmolality rises substantially before any desmopressin is given. Which of the following is the most likely diagnosis?
Answer choices
- APrimary polydipsiaCorrect answer
- BAdrenal insufficiency
- CNephrogenic diabetes insipidus
- DSIADH
- ECentral diabetes insipidus
- FThyroid hormone deficiency
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.