A 35-year-old man develops severe burning in the mouth, profuse salivation, numbness of the tongue and lips, bradycardia, and hypotension within 30 minutes of ingesting a herbal preparation. Death occurs due to ventricular fibrillation. At autopsy, the stomach contents smell of horseradish. The toxin responsible acts by:
- A Persistently activating voltage-gated sodium channels, preventing repolarisation ✓
- B Blocking muscarinic receptors causing paradoxical bradycardia
- C Inhibiting acetylcholinesterase, causing excessive cholinergic stimulation
- D Blocking voltage-gated potassium channels, prolonging action potential
Correct answer: A. Persistently activating voltage-gated sodium channels, preventing repolarisation
Explanation
This is a classic presentation of aconitine poisoning from Aconitum napellus (monkshood/wolf's bane). Aconitine binds to voltage-gated sodium channels and holds them in the open (activated) state, preventing repolarisation. This causes the characteristic burning/tingling paresthesias, hypersalivation, cardiovascular instability, and lethal arrhythmias. The horseradish odour of the stomach contents is a classic autopsy finding. Acetylcholinesterase inhibition and muscarinic blockade have different clinical profiles.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
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Written and medically reviewed by the StethoPrep medical team.