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Salicylate poisoning — USMLE Step 3 MCQ

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HardEmergency MedicineSalicylate poisoningUSMLE Step 3

A 22-year-old woman has tinnitus, vomiting, tachypnea, and confusion after ingesting many aspirin tablets. Arterial blood gas shows pH 7.48 and PaCO2 24 mm Hg; serum bicarbonate is 16 mEq/L. Anion gap is elevated. Which of the following is the most likely explanation for this patient's findings?

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Correct answer: B — Mixed respiratory alkalosis and anion gap metabolic acidosis

Salicylates stimulate the respiratory center causing respiratory alkalosis and impair oxidative metabolism causing anion gap metabolic acidosis.

Reference: American College of Medical Toxicology salicylate toxicity guidance: https://www.acmt.net/