We still don’t know an awful lot about the toxin in grapes, currants and raisins. We only have a rough idea of what the toxic dose is, with doses as low as 2.8g of raisins per kg bodyweight being recorded in poisoning cases. What we do know is that whatever the toxin is (or interaction of several toxins), it causes necrosis (death) of the kidney tissue. We know that they are still toxic whether they are raw or cooked.
We also know that not every dog that eats them will develop poisoning symptoms – this could be either because the dose they ate was very small or just simply pure luck. However, dogs that become poisoned develop acute (sudden) kidney failure, which can be lethal, in some cases even despite early and aggressive treatment.
Unlike chronic kidney failure – where the earliest signs noticed are usually increased urination, dogs with acute kidney failure often produce little to no urine when they first present. Nausea, vomiting and refusal to eat are also common signs. These symptoms can develop in as little a few hours of intoxication but in some cases may not be seen until days afterwards.
Because the consequences of poisoning are so severe and we still don’t know exactly what the lowest toxic doses are, we recommend that if your dog has eaten any grapes, raisins or currants that they are brought in for veterinary treatment as soon as possible. Although there is no “antidote” for raisin/grape toxicity, there are a number of things we can do to lessen the severity of any problems that develop. The earlier we start treatment, the better the chances of a favourable outcome. We can also monitor your dog’s kidney parameters for any signs of damage and to help us determine what the best course of treatment will be.
References:
- Kovalkovičová, N., Šutiaková, I., Pistl, J. & Šutiak, V., Some food toxic for pets, Interdiscip Toxicol [Internet]. 2009 [cited 2017 Mar 12]; Vol 2(3): 169-176 Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2984110/ DOI: 10.2478/v10102-009-0012-4
- Cortinovis, C. & Caloni, F., Household Food Items Toxic to Dogs and Cats, Front Vet Sci [Internet]. 2016 [cited 2017 Mar 12]; 3:26, 1-7 Available from http://journal.frontiersin.org/article/10.3389/fvets.2016.00026/full DOI 10.3389/fvets.2016.00026
- Eubig, P. A., Brady, M. S., Gwaltney-Brant, S. M., Khan, S. A., Mazzaferro, E. M. & Morrow, C. M. K., Acute Renal Failure in Dogs After the Ingestion of Grapes or Raisins: A Retrospective Evaluation of 43 Dogs (1992-2002), J Vet Intern Med [Internet]. 2005 [cited 2017 Mar 12]; 19:663-674 Available from http://onlinelibrary.wiley.com/doi/10.1111/j.1939-1676.2005.tb02744.x/epdf DOI: 10.1111/j.1939-1676.2005.tb02744.x