Chronic Kidney Disease USMLE Step 1 Practice Question
A 44-year-old man with bipolar disorder on lithium for 5 years presents with polydipsia and polyuria. Vital signs: BP 138/85, HR 92, RR 16, Temp 37°C, SpO2 98%. Serum sodium is 150 mEq/L; serum creatinine 1.4 mg/dL. Urine osmolality remains 280 mOsm/kg despite water deprivation and desmopressin administration. Thyroid function tests are normal. Which medication most likely caused this nephrogenic diabetes insipidus?
Answer choices
- ASpironolactone
- BHydrochlorothiazide
- CAcetazolamide
- DDesmopressin
- ELithiumCorrect answer
- FFluoxetine
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.