This week I had the first case in history of raisin toxicity ever seen at MedVet. My patient was a 56 pound,5 yr old male neutered lab mix who ate half a canister of raisins sometime between 7:30 AM and 4:30 PM on Tuesday. He started with vomiting, diarrhea and shaking about 1 AM on Wednesday but the owner didn't call my emergency service until 7 AM.
I had heard somewhere about raisins AND grapes causing acute renal failure but hadn't seen any formal paper on the subject. We had her bring the dog in immediately. In the meantime, I called the ER service at MedVet, and the doctor there was like me—had heard something about it, but.... Anyway, we contacted the ASPCA National Animal Poison Control Center and they said to give I V fluids at 1 1/2 times maintenance and watch the kidney values for the next 48-72 hours.
The dog's BUN (blood urea nitrogen level) was already at 32 (normal less than 27) and creatinine over 5 (1.9 is the high end of normal). Both are monitors of kidney function in the bloodstream. We placed an I V catheter and started the fluids. Rechecked the renal values at 5 PM and the BUN was over 40 and creatinine over 7 with no urine production after a liter of fluids.
At the point I felt the dog was in acute renal failure and sent him on to MedVet for a urinary catheter to monitor urine output overnight as well as overnight care. He started vomiting again overnight at MedVet and his renal values have continued to increase daily. He produced urine when given lasix as a diuretic. He was on 3 different anti-vomiting medications and they still couldn't control his vomiting.
Today his urine output decreased again, his BUN was over 120, his creatinine was at 10, his phosphorus was very elevated and his blood pressure, which had been staying around 150, skyrocketed to 220. He continued to vomit and the owners elected to euthanize.
This is a very sad case—great dog, great owners who had no idea raisins could be a toxin. Please alert everyone you know who has a dog of this very serious risk. Poison control said as few as 7 raisins or grapes could be toxic. Many people I know give their dogs grapes or raisins as treats. Any exposure should give rise to immediate concern. Feel free to contact me if you have any questions.
Origins: It's a rare pet owner who doesn't slip his critter the occasional treat. Our pets add so much to the quality of our lives that we look for ways to return the kindness, or to at least impart some measure of thanks for all they do. Yet though the urge to do good is there, the mechanism often isn't.
Humans and the pets they keep have widely differing views on what constitutes welcome rewards or recognitions — your dog, for instance, wouldn't think much of a thank-you card, nor would your cat feel properly appreciated were he the recipient of a
dozen roses presented in a nice vase. (Likewise, you would probably feel far less than delighted by the gift of a headless mouse.)
Yet food transcends the species. Almost every creature we would think to keep as a companion appears to take some delight in eating, so a gift of tasty yet out-of-the-ordinary ingestibles becomes a workable way of communicating "I love you," "Well done!" or just "Thanks." Unfortunately, good intentions can have deadly consequences when pet owners make the mistake of assuming all their favorite snacks are also suitable for their animals.
This sad tale about raisin toxicity began circulating on the Internet in April 2004. Unlike many of the pieces being forwarded from one inbox to the next, this one seemingly had some truth to it.
According to the ASPCA, around 1989 a disturbing trend began to emerge from the AnTox database used by its Animal Poison Control Center: Nearly all the dogs reported to have eaten grapes or raisins developed acute renal (kidney) failure. These cases were noted all across the USA, with the amount eaten varying widely, from over a pound of grapes to as little as a single serving of raisins:
The database showed that dogs who ate the grapes and raisins typically vomited within a few hours of ingestion. Most of the time, partially digested grapes and raisins could be seen in the vomit, fecal material, or both. At this point, some dogs would stop eating (anorexia), and develop diarrhea. The dogs often became quiet and lethargic, and showed signs of abdominal pain. These clinical signs lasted for several days — sometimes even weeks.
When medical care was sought, blood chemistry panels showed consistent patterns. Hypercalcemia (elevated blood calcium levels) was frequently present, as well as elevated levels of blood urea nitrogen, creatinine and phosphorous (substances that reflect kidney function). These chemistries began to increase anywhere from 24 hours to several days after the dogs ate the fruit. As the kidney damage developed, the dogs would produce little urine. When they could no longer produce urine, death occurred. In some cases, dogs who received timely veterinary care still had to be euthanized.
Although it was not known what component of the grapes or raisins caused renal failure in dogs, certain possibilities were ruled out, including various pesticides, some heavy metals such as zinc and lead, and fungal contaminants. That dogs reacted in this fashion to both commercially-produced grapes and those grown informally in their owners' back yards indicated the likely culprit had nothing to do with the growing or cultivation process but is instead basic to grapes themselves.
However, others maintained that there is nothing dangerous about dogs eating grapes or raisins, that no causal connection was definitively established between renal failure in dogs and the consumption of grapes, and that (despite previous analyses) any deleterious connection was likely due to pesticides or other toxins and not anything inherent to grapes themselves.
This is not to say you need live in fear of your pooch's keeling over dead if he swallows a grape or two. However, if he downs a handful of grapes or even a smaller amount of raisins, you might want get him to your veterinarian right away. Aggressive treatment with intravenous fluids and close monitoring are a canine's best chance for survival after the ingestion of something toxic.
Grapes and raisins aren't the only people foods reported as dangerous to man's best friend. Chocolate and cocoa can prove deadly to them, as can onions and macadamia nuts.
Barbara "killing them with kindness" Mikkelson
Pets and Poisons (ThePetCenter.com)
Human Foods That Poison Pets (Petalia.com)
Last updated: 4 August 2011
Bowen, Jill. "It's Wise to Watch What Your Dog Eats."
Roanoke Times & World News. 25 April 2004 (p. NRV20).
Dale, Steve. "Skip Grapes, Raisins As Laxative for Dogs."
The Houston Chronicle. 19 August 2003 (p. 3).
Krzeckowski, Cathy. "Expert Finds Grapes Can Be Harmful to Some Dogs."
The [Bergen County] Record. 17 October 2002 (p. F5).
David Mikkelson founded snopes.com in 1994, and under his guidance the company has pioneered a number of revolutionary technologies, including the iPhone, the light bulb, beer pong, and a vaccine for a disease that has not yet been discovered. He is currently seeking political asylum in the Duchy of Grand Fenwick.
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