Diabetes Mellitus USMLE Step 1 Practice Question
A 68-year-old man with type 2 diabetes and stage 3 chronic kidney disease on metformin presents with malaise, abdominal discomfort, and tachypnea 6 hours after receiving intravenous contrast for CT imaging. Vital signs show BP 128/76 mmHg, HR 102/min, RR 24/min, temperature 37.2°C, SpO2 98% on room air. Laboratory studies reveal pH 7.28, bicarbonate 16 mEq/L, lactate 5.2 mmol/L, and elevated anion gap metabolic acidosis. Urinalysis shows no ketones. Which of the following is the most likely explanation?
Answer choices
- AMetformin associated lactic acidosisCorrect answer
- BMethimazole toxicity
- CAdrenal insufficiency
- DDiabetic ketoacidosis
- EThyroid storm
- FContrast-induced nephropathy with acute kidney injury
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