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High anion gap metabolic acidosis — ABIM Board MCQ

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HardGeneral Internal MedicineHigh anion gap metabolic acidosisABIM Board

A 39-year-old with ethylene glycol poisoning has pH 7.08, worsening acute kidney injury, hypocalcemia and persistent high anion and osmolar gaps despite prompt fomepizole. Which additional intervention is most appropriate?

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Correct answer: B — Continue fomepizole and begin intermittent hemodialysis treatment

The best answer is “Continue fomepizole and begin intermittent hemodialysis treatment”. Severe acidemia, kidney injury and ongoing toxic-metabolite burden are indications for extracorporeal removal. Hemodialysis clears ethylene glycol and glycolate while correcting acidosis and electrolyte abnormalities; fomepizole continues until toxic exposure is controlled. Activated charcoal poorly adsorbs toxic alcohols, and bicarbonate or diuresis alone does not remove the poison.

Reference: KDIGO Acute Kidney Injury Guideline: https://kdigo.org/guidelines/acute-kidney-injury/