Ingestion of grapes or raisins has resulted in development of anuric renal failure in some dogs. Cases reported to date have been in dogs; an anecdotal report exists of a cat developing renal failure following ingestion of 1 cup of organic raisins. It is not known why many dogs can ingest grapes or raisins with impunity while others develop renal failure following ingestion. The condition has not been reproduced experimentally.

Pathogenesis

The mechanism of toxicity is unknown. Affected dogs develop anuric renal failure within 72 hr of ingestion of grapes or raisins. Estimated amounts of grapes associated with renal injury in dogs are ~19 g/kg; amounts of raisins associated with signs begin at ~3 g/kg.

Clinical Findings

Most affected dogs develop vomiting and/or diarrhea within 6–12 hr of ingestion of grapes or raisins. Other signs include lethargy, anorexia, abdominal pain, weakness, dehydration, polydipsia, and tremors (shivering). Serum creatinine levels tend to rise early and disproportionately compared to serum urea nitrogen levels. Oliguric or anuric renal failure develops within 24–72 hr of exposure; once anuric renal failure develops, most dogs die or are euthanized. Transient elevations in serum glucose, liver enzymes, pancreatic enzymes, serum calcium, or serum phosphorus develop in some dogs.

Diagnosis

Diagnosis is based on history of exposure, along with clinical signs. Other causes of renal failure (eg, ethylene glycol, cholecalciferol) should be considered in the differential diagnosis.

Treatment

Prompt decontamination of significant ingestion of raisins or grapes is recommended. Emesis can be induced with 3% hydrogen peroxide (2 mL/kg; no more than 45 mL), followed by activated charcoal. With large ingestions or in cases where vomiting and/or diarrhea has spontaneously developed within 12 hr of ingestion of grapes or raisins, aggressive fluid diuresis for 48 hr is recommended. Renal function and fluid balance should be monitored during fluid administration. For oliguric dogs, urine production may be stimulated by using dopamine (0.5–3 μg/kg/min, IV) and/or furosemide (2 mg/kg, IV). Anuric dogs are unlikely to survive unless peritoneal dialysis or hemodialysis is performed; even then, the prognosis is guarded.

Last full review/revision March 2012 by Sharon M. Gwaltney-Brant, DVM, PhD, DABVT, DABT