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Simple febrile seizure — USMLE Step 3 MCQ

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HardPediatrics (well-child, chronic management)Simple febrile seizureUSMLE Step 3

A 38-year-old is rescued unconscious from an enclosed building fire. He has soot in the oropharynx, hypotension, confusion after awakening, lactate 12.4 mmol/L, and carboxyhemoglobin 18%. High-flow oxygen and airway support are underway. Which additional treatment is most appropriate now?

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Correct answer: A — Give intravenous hydroxocobalamin now while continuing airway and circulatory support

The best answer is “Give intravenous hydroxocobalamin now while continuing airway and circulatory support”. Enclosed-space smoke exposure, soot, altered mental status, hemodynamic compromise, and lactate above 10 mmol/L create a high clinical suspicion for cyanide poisoning. Hydroxocobalamin is given immediately with airway, oxygenation, and circulatory support; treatment should not await a cyanide level. Nitrite-induced methemoglobinemia can worsen oxygen delivery when carbon monoxide exposure coexists.

Reference: FDA Cyanokit Prescribing Information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/022041s008s009lbl.pdf