Chronic Kidney Disease USMLE Step 1 Practice Question
A 6-year-old boy presents with growth failure, polyuria, bone pain, and generalized weakness. Vital signs show BP 118/76 mmHg, HR 92/min, RR 20/min, temperature 37°C, and SpO2 98% on room air. Laboratory studies demonstrate normal anion gap metabolic acidosis (pH 7.32), serum phosphate 2.1 mg/dL, glucosuria with normal serum glucose (98 mg/dL), and aminoaciduria. Serum creatinine is normal. Renal ultrasound shows no structural abnormalities. Which of the following best explains this disorder?
Answer choices
- AAutoimmune destruction of alpha intercalated cells
- BExcess aldosterone activity in the collecting duct
- CAntibodies against the glomerular basement membrane
- DGeneralized proximal tubular dysfunction causing Fanconi syndromeCorrect answer
- EPostobstructive damage to the medullary collecting duct
- FSelective dysfunction of the thick ascending limb of the loop of Henle
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