Currants, raisins and grapes both with and without seeds are toxic to dogs. Foods containing these items such as mince pies, Christmas pudding and raisin bread also have the potential to cause acute kidney failure.
The problem with grape toxicity is that no one has found what the toxic levels are in dogs. We can say that the more grapes that a dog eats the more likely it is for a problem but also there is a significant amount of individual variation between dogs. This means that even one grape can be enough to be toxic in some dogs.
We also do not know the exact process by which the grapes cause kidney damage. Theories include mycotoxins, or a compound called salicylate in the grapes may be the cause. Hopefully in the future with research we will find the exact cause but for now it remains unknown.
If you find that your pet has eaten grapes, raisins or currants you need to immediately head to your veterinary clinic. The sooner action is taken the better in these poisoning cases.
When at the vet clinic your veterinarian will induce vomiting if the ingestion has been recent. This is to get the grapes back out of the body in the hope they will not continue to do harm as they pass through the gastrointestinal tract. We also feed a product called activated charcoal which lines the gastrointestinal tract and helps to stop absorption of the poison.
As the grapes cause kidney damage, it is recommended to start IV fluids for 24-48 hours, and to run blood tests both before and after the 48 hour mark to assess if there is kidney damage. Sometimes pets need to stay on IV fluids for up to a week to help support their kidneys through the poisoning incident. As you can imagine the cost of hospitalisation for 2-7 days is considerable.
If you don’t catch your pet eating grapes the most common sign they present with is vomiting and lethargy around 1-2 days after ingestion. This progresses to abdominal pain, excessive thirst and urination sometimes diarrhoea and extreme lethargy. If it progresses to no urination this is a very poor prognostic indicator and the outlook is much more guarded.
There is no definitive way to diagnose grape toxicity, veterinarians are very reliant on the history of ingestion so if you think there is any chance your pet may have eaten grape or grape containing products it’s really important to communicate this to your veterinarian.
There is also no known antidote to grape poisoning, the only treatment we have is supportive so again urgent action is needed if you think your pet has eaten grapes or raisins.
The prognosis depends on the amount eaten and the severity of renal damage. This can be assessed through blood and urine tests. Some patients make a full recovery and others progress to kidney failure and have a very poor prognosis. The inability to make urine is a very bad sign as this is a sign that the kidneys have suffered severe damage and the kidneys cannot regenerate (repair) very well like other parts of the body.
Prevention really is better than cure with grape and raisin toxicity. Keep grapes out of reach of pets and if on a table, place in the middle and watch carefully for your pet trying to jump up to eat the grapes. When you have guests over for gatherings and grapes are on offer just let people know that grapes are toxic to dogs so that no one accidently feeds grapes to your dog.
Fruit loaf and other fruit containing products again should be stored in cupboards or out of reach of pets. They have the potential to be just as fatal as grapes so be on your guard when having these products in the home.