Grapes and sultanas are toxic to dogs. They will cause acute kidney failure. The amounts involved can vary from a half kilo of grapes to as little as a single serving of sultanas. It is unknown what is the exact cause of the kidney damage.
Clinical signs start typically within a few hours of ingestion. Vomiting coincides with anorexia (stop eating) and then diarrhoea. The dogs often become quiet and lethargic, and show signs of abdominal pain. These clinical signs can last for several days and sometimes even weeks.
Immediate treatment at a veterinary hospital should be sort. Blood tests can detect kidney changes in as little as 24 hours after ingesting grapes. As the kidney damage progresses, the dog produces little urine. When they can no longer produce urine, death occurs. In some cases, euthanasia will still be necessary in some cases that have received timely care.
Treatment involves inducing the dog to vomit and then administering activated charcoal to help prevent absorption of potential toxins. The dogs should be hospitalised and placed on intravenous fluids for a minimum of 48 hours. A veterinarian will monitor the blood chemistry daily for at least 3 days following the ingestion. If all the blood work is normal after three days, its unlikely that kidney failure will occur. If a dog shows evidence of kidney failure, the intravenous fluids must be continued, and other medications should be used to stimulate urine production.