Acid-Base Disorders USMLE Step 1 Practice Question
A 63-year-old man with long-standing diabetes mellitus comes to the clinic because of fatigue. Medications include lisinopril and ibuprofen as needed for back pain. Laboratory studies show potassium 5.9 mEq/L, bicarbonate 18 mEq/L, and a normal anion gap. Which of the following is the most likely explanation for this patient's acid-base disorder?
Answer choices
- ALactic acid accumulation from tissue hypoperfusion
- BChronic vomiting with chloride depletion
- CProximal bicarbonate wasting from Fanconi syndrome
- DHyporeninemic hypoaldosteronismCorrect answer
- EDistal hydrogen ion secretion defect with nephrolithiasis
- FMetformin-induced impaired ammonium excretion
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