Treat the ventricular tachycardia with a lidocaine drip and address hyperactivity/seizures with diazepam (Valium ®) or methocarbamol. If response to diazepam inadequate, consider barbiturates like phenobarbital (given slowly).
This is a classic presentation of severe chocolate toxicity, due to toxic methylxanthine alkaloids (e.g., theobromine, theophylline, caffeine). Common around Halloween, Christmas, and Valentine’s Day holidays, see excitement, seizures, and arrhythmias. This dog’s ECG shows ventricular tachycardia (V-tach).
Most chocolate toxicities are milder – hyperactivity, vomiting, urinating, diarrhea.
Decontamination with emesis (induced with apomorphine) can be helpful up to eight hours after exposure in asymptomatic dogs.
If animal is sedated because of seizures, consider gastric lavage. If vomiting is controlled, give activated charcoal (AC) only if the dog ate a lethal dose. Chocolate will increase the risk of hypernatremia from AC, so the benefit must outweigh the risk. If AC is given, monitor for hypernatremia and associated signs (tremor, ataxia, seizures).
Tx arrhythmias depending on type – usually a tachycardia; give LIDOCAINE for V-tach or BETA-BLOCKERS (propranolol/esmolol) for supraventricular tachycardias.
Chocolate toxicity from most toxic to least toxic: cacao beans and baking chocolate are worse than semisweet chocolate which is worse than milk chocolate. 49 grams of baking chocolate (one 2-oz bar) can kill a 7-kg dog. It would take 420 grams of milk chocolate (about eight 2-oz bars) bars to kill a 7-kg dog.
Image courtesy of Dr. Terri DeFrancesco.
