Grape & raisin toxicity
Raisins, grapes, and currants are a potentially toxic food to dogs. All versions of these foods (red or green grapes, seedless or seeded grapes, etc.) are considered dangerous to dogs. Although the mechanism of toxicity has not been discovered, it is known that grape and raisin ingestion can cause acute kidney failure, even if only a small number of grapes or raisins are eaten. The toxic component is suspected to be tartaric acid and because the content can vary, there is variable toxicity with some animals not developing any signs. There seems to be a correlation in toxicity with larger numbers of grapes/raisins ingested and susceptibility in certain dogs such as those with underlying kidney disease. Grapes and raisins of the Vitis species can cause vomiting, diarrhea, anorexia, and potentially acute kidney injury within 24- 48 hours of ingestion in dogs. Cats do not seem to be affected.
Ingestion of large numbers of grapes or raisins may cause immediate vomiting in dogs, though some dogs will remain asymptomatic. If treatment is not pursued and kidney failure develops, symptoms may include vomiting, decreased appetite, lethargy, and dehydration. Some cases will show abdominal pain and changes in urine production.
Interestingly, some dogs show no symptoms and do not develop toxicity. Animals that exhibit spontaneous vomiting within the first 24 hours of exposure are more likely to develop renal damage.
Treatment:
If the ingestion of grapes or raisins was within 6-8 hours, the recommendation is to induce vomiting to remove any residual fruit in the stomach. Activated charcoal has not been shown to reduce the risk of toxicity so it is no longer recommended by ASPCA Animal Poison Control Center. Depending on the amount ingested, timeframe since ingestion, success of emesis, and underlying health of the animal, hospitalization for intravenous fluids and monitoring for 48 hours may be recommended. Baseline bloodwork with rechecks every 24 hours for three days will be recommended to detect any changes in kidney values. Many dogs will remain asymptomatic during this time frame and no longer need follow up care. For patients that show elevated kidney values or clinical signs of toxicity, continued hospitalization may be required.
Prognosis:
Prognosis is excellent for dogs who are treated quickly and do not develop kidney damage. Dogs who develop acute kidney failure secondary to grape, raisin toxicity have a variable prognosis that depends on severity of illness,
any delays in treatment, and pre-existing kidney disease.