A recent ASPCA Animal Watch, warns that grapes and raisins can be very dangerous to dogs and that until recently, these dangers were unknown.
Through a sophisticated database system maintained by the ASPCA Animal Poison Control Center (APCC), veterinarians began noticing a trend in dogs who had eaten grapes or raisins. In nearly every case, the dogs developed acute kidney failure. As additional cases were reported, enough data was generated to help veterinarians identify a severe danger and to develop treatment for dogs at risk of kidney failure from ingesting these fruits.
Data showed that dogs who ate grapes and raisins, in large or small amounts, typically vomited within a few hours. 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 and would 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.
Blood tests on these animals showed consistent patterns of elevated blood calcium and other substances that indicate reduced kidney function. As the kidney damage developed, the dogs would produce greatly reduced amounts of urine, and when they could no longer produce urine at all, death occurred.
No one knows why the fruit caused the dogs to become ill. Grapes and raisins have been screened for pesticides, heavy metals, and fungal contaminants and so far, all results have come back negative, even from grapes and raisins eaten directly off the vine.
Even though the exact cause of the kidney failure is unknown, dogs who ingest grapes and raisins can be treated successfully to prevent progression of the disease. If your dog eats raisins, a veterinarian should be consulted, and most likely the animal will need hospitalization so that intravenous fluids may be administered and blood chemistry monitored. Some dogs may need a form of dialysis which utilizes the membranes surrounding the abdominal organs to filter waste products that are normally filtered by the kidneys.