Osteochondritis dissecans — MRCEM SBA MCQ

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HardKnee InjuriesOsteochondritis dissecansMRCEM SBA

A patient with an unknown overdose develops coma, generalised seizures, hypotension, sinus bradycardia and progressive QRS widening. Empty packets of several antihypertensives are found. Which beta blocker most characteristically produces this combined sodium-channel and central nervous system phenotype?

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Correct answer: C — Propranolol

The best answer is “Propranolol”. Propranolol is highly lipophilic, readily enters the central nervous system and has membrane-stabilising sodium-channel-blocking activity. Severe overdose can therefore cause coma and seizures together with bradycardia, hypotension and QRS widening, unlike the more purely beta-adrenergic phenotype of many alternatives. Sotalol is another distinctive beta blocker but causes potassium-channel blockade and QT prolongation rather than this QRS/seizure pattern. Recognition matters because treatment may require sodium-channel-directed therapy as well as standard beta-blocker-poisoning support.

Reference: Propranolol overdose following prescription for anxiety: https://pmc.ncbi.nlm.nih.gov/articles/PMC11875730/