Chronic Kidney Disease USMLE Step 1 Practice Question
A 17-year-old boy presents with severe hypertension (BP 160/105 mmHg) discovered during a sports physical. Vital signs show HR 88 bpm, RR 16, temperature 37°C. Laboratory studies reveal hypokalemia (K+ 2.9 mEq/L), metabolic alkalosis (HCO3− 32 mEq/L), low plasma renin activity, and suppressed aldosterone level. Urine potassium is elevated. He denies licorice use and takes no medications. Which of the following is the most likely underlying mechanism?
Answer choices
- AConstitutive activation of epithelial sodium channels in principal cellsCorrect answer
- BLoss of bicarbonate reabsorption in the proximal tubule
- CAutonomous aldosterone secretion from the adrenal cortex
- DInhibition of Na K 2Cl transport in the thick ascending limb
- EDefective type IV collagen in basement membranes
- FApparent mineralocorticoid excess from 11-beta-HSD2 deficiency
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