Grape Toxicity

Murpy’s owners just thought they were paying another minor installment on their dog tax when they caught him halfway through gulping down the container of table grapes they had just gotten to compliment their lunch that day. After all, you turn your back for a second and that dog is into everything. They cleaned up the remains and went about their business.

A few days later Murphy just wasn’t acting himself. He never misses breakfast, but he had met his morning meal with complete indifference that day. At work Murphy’s mom mentioned that he wasn’t acting quite right, but the only thing he had gotten into lately was the grapes. Fortunately a co-worker had heard something about grapes being toxic to dogs, and that triggered a call from Murphy’s owners to us.

We had him come down immediately. I had a moment of despair when I got the results of Murphy’s blood work and saw kidney values that were at least twice the highest values that I had ever seen in any other patient. The previous record holders had not survived. That told me that the grapes had put him into sudden, extreme kidney failure and that the chances that he would pull through this were very slim.

Apparently somebody forgot to tell Murphy about his odds, so after a week of aggressive fluid therapy and equally aggressive treatment to control the nausea and stomach ulcers that accompany kidney failure his kidneys recovered from what easily could have been a life-threatening swoon and decided to work again. We finally had to send him home because he was too boisterous to keep hospitalized any longer, but in spite of the fact that he is feeling great now he still faces the specter of permanent kidney damage that may manifest later down the road.

Who would think that something as benign as grapes could cause such extreme problems in a dog? Grape toxicity is a fairly newly discovered entity in the veterinary world, and for that reason it is not as widely known to the general public. The exact toxic principle has not been discovered yet, but it is possible that it is caused by a chemical in the grapes that some dogs can metabolize into a different compound which is then very poisonous to their kidneys. Some dogs seem able to eat grapes with no ill effects whatsoever, and that may be because their metabolism is slightly different and doesn’t create the toxic compound when they ingest grapes. So far there is no clearly defined breed tendency for this problem. Labradors may be slightly over represented, but they tend to be a little over represented in the population of dogs that knock over the grocery bags and eat anything they can get a hold of.

Raisins have the same potential to cause kidney failure that grapes do, and can in fact be more dangerous because their smaller size allows a greedy dog to ingest a larger volume even more quickly. Green grapes and red grapes both seem to have the same danger of toxicity.

It is suspected that cats could also potentially be affected by grape toxicity, but because they are carnivores they aren’t as attracted to grapes and raisins. We just don’t see lots of cases where cats have sneaked into the cupboard to gorge themselves on raisins.

If you have the good luck to witness your pet ingesting grapes, or anything else that could potentially be poisonous, you will have a small window in which you may be able to prevent problems entirely. If you are not sure you can always call your veterinarian. Non-veterinary poison call centers may be able to give helpful information for some toxicities, but none would be likely to give accurate information about something like grape toxicity that does not affect humans. If your pet can be made to vomit the toxic substances before they can be absorbed then the poisoning can often be averted, or at least reduced. Your veterinarian has some effective ways to get that done. Sometimes people think that because their pet is not instantly convulsing and foaming at the mouth that everything must be OK, but most toxic substances don’t cause any ill effects until they have been completely absorbed into the system and then have had a day or two to cause enough organ damage to make a pet feel sick, and by that point it is much too late to do anything to reduce the exposure.

Knowledge is the most important tool you can have. Now that you know that grapes and raisins can cause serious problem you can add two more things to you list of items to keep out of reach of voracious dogs.