A 28-year-old male presents with severe bradycardia, hypotension, paresthesias, and burning sensation of mouth and throat 30 minutes after consuming herbal tea. ECG shows widened QRS with ventricular ectopics. Which toxin is MOST likely, and what is its primary mechanism?
- A Aconitine — persistent activation of voltage-gated sodium channels ✓
- B Atropine from Datura — muscarinic acetylcholine receptor blockade
- C Oleandrin — inhibition of Na+/K+ ATPase pump
- D Abrin — inhibition of ribosomal protein synthesis
Explanation
Aconitine (from Aconitum napellus/ferox) is a classic cause of rapid-onset neurological and cardiac toxicity. It binds to and persistently activates voltage-gated sodium channels (VGSCs), preventing inactivation, leading to sustained membrane depolarization. This causes initial neurological features (paresthesias, burning sensations), followed by bradycardia, hypotension, and life-threatening arrhythmias including VT/VF. The QRS widening reflects the sodium channel blockade effect on myocardial conduction. Datura (B) causes anticholinergic features (dry, hot, tachycardia). Oleander (C) causes digoxin-like toxicity with high potassium. Abrin (D) causes delayed cytotoxic effects.
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.