Chronic Kidney Disease USMLE Step 1 Practice Question
A 63-year-old man with long-standing diabetes mellitus presents for routine follow-up. Vital signs: BP 142/88 mmHg, HR 76/min, RR 16/min, temp 37.2°C. He takes lisinopril daily. Laboratory studies show potassium 5.9 mEq/L, bicarbonate 18 mEq/L, chloride 112 mEq/L, normal anion gap, and creatinine 2.8 mg/dL. Urinalysis shows 2+ proteinuria but no hematuria. Which of the following is the most likely cause of these abnormalities?
Answer choices
- AVomiting with extracellular fluid contraction
- BHypoaldosteronism causing impaired distal potassium and hydrogen secretionCorrect answer
- CExcess distal hydrogen secretion by alpha intercalated cells
- DLoop diuretic induced chloride depletion
- EDefective proximal bicarbonate reabsorption with phosphaturia
- FTrimethoprim-induced blockade of apical sodium channels in the collecting duct
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.