Antifreeze (ethylene glycol) is a freeze preventive used in engines and other heat transfer applications, such as HVAC chillers and solar water heaters. It is a common substance to have in garages this time of year. The problem with traditional antifreeze is that it is attractive to pets because it has a very sweet taste but only a small amount is needed to kill an animal.
After ingestion, antifreeze is quickly absorbed from the stomach tract; in dogs, this occurs within 3 hours. As the substance is broken down in the body, reactions in the liver and kidneys can cause severe damage to the body.
If your pet ingests antifreeze, the onset of signs is almost immediate and resembles alcohol (ethanol) intoxication. Dogs and cats vomit due to irritation of the stomach and intestines, drink more water, urinate more often and have neurologic signs. You may notice your pet stumbling, falling over, or having slow reflexes. As the central nervous system begins to slow down, cats and dogs drink less but the kidneys continue to produce more urine, resulting in severe dehydration. Renal failure usually develops between 12 and 24 hours in a cat and 36 and 72 hours in a dog.
Diagnosis can be difficult if someone did not witness ingestion and because many other things can look the same as antifreeze toxicity. Within 3 hours of ingestion, there are significant changes on bloodwork and in the urine that can help a veterinarian diagnose ethylene glycol toxicity. One of the most common changes is the presense of calcium oxalate crystals forming in the urine. These can be seen as early as 3 and 6 hours after ingestion in cats and dogs, respectively. Commercial test kits are also helpful in detecting blood concentrations.
The prognosis after ingestion varies based on the amount of time that elapses between ingestion and initiation of treatment. The goal of treatment is to decrease absorption of the antifreeze and increase excretion out of the body. If ingestion has been recent, your veterinarian will be able to induce vomiting and give activated charcoal to prevent further absorption. If hours have passed between ingestion of antifreeze and your veterinarian being able to treat the pet, prognosis for survival is poor.
Effective January 1, a new Maryland law will require a bitter-tasting additive be put in antifreeze. The law was pushed by Lynne Gillis, from Huntingtown, MD, who testified at a legislative hearing last winter about her hound-mix dog, Nikko, who died after ingesting antifreeze. Unfortunately Nikko did not survive the poisoning, but the law hopes to prevent other deaths. The Maryland Antifreeze Bittering Agent Act, which requires retailers to stock engine coolants with the additive denatonium benzoate, was to begin Oct. 1, but lawmakers agreed to a later date to allow retailers to clear their inventory.
