A few incidents recently of dogs overindulging on chocolate. In one case the offender pulled lots of foil covered chocolate decorations off the Christmas tree and ate them including the foil! Other cases involved raiding boxes of chocolates. All such cases tend to have some impact on the digestive system; diarrhoea or difficulty passing the wrappers when they reach the other end! Boxes of chocolates with sweet centres don’t usually cause anything more serious than this, but the higher the chocolate content the more serious the problem. Plain and cooking chocolate are the worst with only a few squares needing to be consumed by a toy breed in order to cause unwanted effects. Symptoms include trembling, inco-ordination and salivation.
In a couple of cases of exessive consumption this year we injected an emetic – a drug to induce vomitting. This drug is not cheap but it’s almost always effective, though it needs to be given within an hour or two of ingestion of a poison to be worthwhile or the stomach will already have emptied. If it’s too late for the emetic then treatment is ‘symptomatic’ – i.e. as with most poisons there is no specific antidote, but we use nursing and drugs to reduce the severity of symptoms along with intravenous fluids to ‘flush out’ toxins.
The most frequent poison we have to deal with in dogs is rat bait – usually in the form of a blue grain which stops blood clotting so that the poisoned animal bleeds to death via small internal injuries which would usually cause no symptoms. In this case there is a useful antidote – vitamin K – which restores the blood’s ability to clot, though it needs to be given for several days.
In the case of cats I suspect the most frequent cause of symptoms due to poison ingestion is antifreeze. This causes kidney failure, but, as there are other causes of the same problem, combined with the fact that most owners do not know what their cats are getting up to when they are out and about, confirmation of the cause is not easy some time later when the poor cat is dying.