Ingestion of grapes or raisins has been associated with development of anuric renal failure in some dogs. Cases reported to date have been in dogs; anecdotal reports exist of renal failure in cats and ferrets after ingestion of grapes or raisins. It is not known why many dogs can ingest grapes or raisins with impunity whereas others develop renal failure after ingestion. The condition has not been reproduced experimentally, although raisin extracts have been shown to cause damage to canine kidney cells in vitro.
Ingestion of grapes, raisins, and Zante currants, all members of the Vitis genus, has occasionally been associated with development of renal failure in dogs. True currants of the genus Ribes have not been associated with renal injury. The toxic principle and exact mechanism of toxicity are unknown, although the primary injury occurs in the proximal renal tubular epithelium. Affected dogs develop oliguric or anuric renal failure, generally within 72 hours of ingestion of grapes or raisins. A clear dose-response relationship has not been determined, but ingestion of as few as 4–5 grapes was implicated in the death of an 18-lb (8.2-kg) dog.
Most dogs with raisin or grape toxicosis develop vomiting and/or diarrhea within 6–12 hours of ingestion of grapes or raisins. Other signs include lethargy, anorexia, abdominal pain, weakness, dehydration, polydipsia, and tremors (shivering). Serum creatinine concentrations tend to rise early and disproportionately compared with serum urea nitrogen concentrations. Oliguric or anuric renal failure develops within 24–72 hours of exposure; once anuric renal failure develops, most dogs die or are euthanized. Transient increases in serum glucose, liver enzymes, pancreatic enzymes, serum calcium, or serum phosphorus concentrations develop in some dogs.
Recommended treatment of raisin or grape toxicosis in cases of symptomatic ingestion is prompt decontamination of ingested contents. Emesis may be induced with administration of 3% hydrogen peroxide (2 mL/kg; no more than 45 mL), followed by activated charcoal. With large ingestions or in cases in which vomiting and/or diarrhea has spontaneously developed within 12 hours of ingestion of grapes or raisins, administration of aggressive intravenous fluid diuresis for a minimum of 48 hours is recommended. Renal function and fluid balance should be monitored during fluid administration. For oliguric dogs, urine production may be stimulated by administering dopamine (0.5–3 mcg/kg per minute, IV) and/or furosemide (2 mg/kg, IV). Anuric dogs are unlikely to survive unless peritoneal dialysis or hemodialysis is administered; even then, the prognosis is guarded.
Ingestion of Vitis spp has been associated with development of renal failure in some dogs.
Because the mechanism of action and toxic principle are unknown, decontamination of contents in cases of symptomatic exposure to Vitis spp is recommended.
Treatment entails early decontamination of ingested contents and intravenous fluid diuresis while monitoring renal function.