Presenter: Paul Aldridge Veterinary Surgeon BVSc CertSAS MRCVS, Rowan Veterinary Centre
‘Tis the season to be jolly,’ that is until you are faced with a dog having eaten half a Christmas cake and a whole chocolate orange. I work at a practice which covers emergency out of hours work for all surrounding practices, and ingestion of toxins is one of the more common scenarios we encounter. Chocolate is unsurprisingly one of the most frequently ingested toxins and at this time of year remains top of the list alongside raisins as a component of the dreaded if not delicious Christmas cake.
Paul Aldridge led last week’s webinar discussing seasonal emergencies and advised on the general approach for managing toxicities. The four key components to this management strategy are;
- Keeping the patient alive (goes without saying)
- Reducing or eliminating further absorption
- Administering medical therapy based on a working diagnosis of a known toxin
- Providing an antidote where necessary.
This approach is the same regardless of the toxin, and inducing emesis can be a very useful starting point for limiting absorption. Many texts state that inducing emesis is only useful if performed within an hour of ingesting the toxin. However Paul advises this can vary significantly dependent on the toxin. For example NSAIDs tend to get absorbed very quickly and emesis is only likely to prove useful within 30 minutes of ingestion. Toxins such as raisins and chocolate, however, can be slowly absorbed and the induction of emesis even after two hours post ingestion could still be effective. Paul also explained that emesis is only likely to cause emptying of 40-60% of the stomach contents. Feeding dogs a small amount prior to inducing vomiting could aid with better emptying of the stomach.
I won’t dwell too much on chocolate toxicity within this blog as I suspect this is the toxin we are all familiar with. However Paul delivers an excellent refresher on the subject including pertinent updates such as the VPIS increasing the toxic dose of chocolate in dogs. It is also worth remembering that diazepam is often ineffective in managing seizures associated with chocolate toxicity. Treatment with either phenobarbitone or propofol would be an appropriate treatment option for these cases.
Xylitol is perhaps a less familiar toxin but with its presence as an artificial sweetener in many food stuffs including chewing gum, mints, mouthwash and medicines, it is a toxin we are likely to encounter at some point in our career. Ascertaining the presence of xylitol within food stuffs may also be difficult as there is no legal obligation to list it within a particular food products ingredients. Xylitol toxicity causes a profound and prolonged hypoglycaemia in dogs which means cases will present with neurological signs. This can cause confusion as these signs mimic the effects of other toxins such as chocolate, which also have neurological effects. For this reason Paul advises always checking the blood glucose of a patient which, if low, points more towards xylitol toxicity (hypokalaemia may also be observed in these patients). Treatment involves giving oral or intravenous glucose infusions over several days as the hypoglycaemia associated with xylitol can be prolonged. Some patients will also develop liver dysfunction and failure at higher xylitol doses although it does appear to be an idiosyncratic reaction with animals having individual susceptibility.
Paul delivered invaluable tips and advice on several toxicities seen at this time of year including ethylene glycol and raisin toxicities. Paul reminded us the toxin causing substance within grapes and raisins is unknown and, as animals appear to have individual susceptibility to this unknown substance, there is no safe level of ingestion for any foods containing these ingredients. So if you do happen to be working over Christmas (which most of us will be at some point) this webinar can only fill you with confidence the moment that Christmas cake, chocolate eating Labrador comes through your consulting room door.
The Stethoscope (MRCVS)