4470 El Camino Real

Los Altos, California 94022

Veterinarian Always on Duty

Antifreeze Poisoning

Smokey's Toxic Drink

Smokey, a 4 1/2 year old male castrate Labrador retriever, presented to Adobe on a Sunday after an episode of weakness two days earlier. Smokey and his parents had one up to their cabin in the Sierras on Friday night. Within a couple hours of arriving, the owners noticed that he was staggering around drunkenly, unable to keep his balance. The next morning, he seemed a little less disoriented but nauseous, and he was drinking tons of water. Thinking hat he might be having problems with the altitude, his owners packed up the car and brought Smokey back to the Bay Area. By the time Smokey made it to his appointment on Sunday, he was his usual perky self except that he continued to drink vast quantities of water.

After hearing his owners' story, I asked them whether Smokey may have had a drink from the toilet bowl in the mountains. The answer was yes, he sure did. The next question was whether the owners use antifreeze in the toilet to prevent the water from freezing when nobody was using the cabin. The answer to that question was also yes. We ran some blood work on him and checked a urine sample, and sure enough, his lab work supported a diagnosis of antifreeze poisoning.

Since Smokey appeared to be doing so well, he was treated as an outpatient. The owners watched him and his urine output closely and brought him back in two days for follow-up blood work. At that visit his lab work demonstrated a deterioration in his kidney function, despite the fact that Smokey looked and felt good otherwise. The decision was made to hospitalize him and have him on aggressive iv fluid therapy to diminish further damage to his kidneys. Dr. Tegzes, a toxicologist at UC Davis, was consulted, and he confirmed the presumptive diagnosis of ethylene glycol poisoning. After four days in the clinic, Smokey looked and felt great, his kidney function had improved, and he was released from the hospital to be cared for at home. One and a half weeks later, his blood work had returned to normal.

Smokey was extremely lucky to have consumed a sub lethal dose of this common household poison. Ethylene glycol (EG), or antifreeze, causes stomach pain, vomiting, neurological signs, and ultimately kidney failure in dogs and cats. Signs of ethylene glycol poisoning include vomiting, abdominal pain, drinking lots of water, and uncoordinated or "drunkenness," and these signs may appear within 30 minutes of ingestion. In addition to using antifreeze as a coolant in vehicles, many people put ethylene glycol in the household plumbing to prevent the water in the pipes from freezing. In California, this is clearly more of a problem in colder areas like the mountains, where a visit to the toilet bowl for a refreshing drink by a dog or cat can result in severe illness or death. The lethal dose of undiluted EG for dogs is 6.6 ml/kg and the lethal dose for cats is 1.5 ml/kg. Thus a typical 40 lb dog has a lethal dose of 120 ml or roughly half a cup, while a typical cat has a lethal dose of 6.8 cc or a little over one teaspoon! Unfortunately, ethylene glycol is a sugar-like substance that may taste good to pets, thus many pets will actively drink it if they have access to it. The best way to prevent death or permanent damage is to get your pet to a veterinarian as soon as you suspect an ingestion has occurred.

Another kind of antifreeze/solvent, called propylene glycol (marketed under the brand name SIERRA), can also be lethal to pets, but death occurs at higher doses than with EG (9 ml/kg for a dog) and a toxic ingestion is more treatable. The toxic mechanism is a little different than that for ethylene glycol, as the substance primarily causes the blood to become extremely acidic. With any type of poison, as soon as you think an ingestion has occurred, you should call a veterinarian immediately for advice. The staff and veterinarians at Adobe are available 24 hours a day to guide you in scary situations like this.

Date: February 2003

Species: Dog

Diagnosis: Antifreeze poisoning

Doctor: Nicolette Zaraday

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