Ethylene Glycol Poisoning in Dogs

What is ethylene glycol?

Ethylene glycol, a sweet-tasting, odorless liquid, is the active ingredient in most automotive antifreeze products. Ethylene glycol can also be found, in lower, less harmful, concentrations, in some windshield de-icing agents, hydraulic brake fluid, motor oils, solvents, paints, film processing solutions, wood stains, inks, and printer cartridges.

How do dogs get ethylene glycol poisoning?

Dogs may be attracted to ethylene glycol by its sweet taste. Many animals voluntarily drink ethylene glycol if antifreeze is spilled or leaks onto garage floors or driveways. Ethylene glycol has a very narrow margin of safety, which means a tiny amount can result in severe poisoning. As little as half a teaspoon per pound of a dog’s body weight can result in death.

What are the signs of ethylene glycol poisoning?

Ethylene glycol poisoning is divided into three stages.

Stage 1 (within 30 minutes of ingestion): The signs include lethargy, vomiting, incoordination, excessive urination, excessive thirst, hypothermia (low body temperature), seizures, and coma.

Stage 2 (12 to 24 hours after ingestion): Some of the signs seem to dramatically improve, luring pet owners into a false sense of security. However, during this stage, dogs become dehydrated and develop an elevated breathing and heart rate.

Stage 3 (36 to 72 hours after ingestion): At this stage, signs of severe kidney dysfunction may occur, characterized by swollen, painful kidneys and the production of minimal to no urine. Progressive depression, lethargy, lack of appetite, vomiting, seizures, coma, and death may be seen.

It is critical that you contact your veterinarian or Pet Poison Helpline, a 24/7 animal poison control center, at 1-800-213-6680, if you know or even suspect that your pet has consumed ethylene glycol, or if they exhibit any of the early symptoms. Do not wait; time is of the essence and immediate treatment is essential. Dogs must be treated within 8–12 hours of ingesting antifreeze, as the antidote only has a short timeframe to work. Left untreated, the animal may die.

How do veterinarians confirm ethylene glycol poisoning?

The best way to confirm ethylene glycol poisoning is to measure the blood concentration of ethylene glycol. This test can be performed at some veterinary diagnostic laboratories or human hospitals. This testing method is accurate, but not always available in the middle of the night. 

Some veterinary hospitals have an in-house test kit that can detect the presence of ethylene glycol in the bloodstream. However, these types of tests may not be as accurate, and false positives can be seen (from exposures to other alcohols, such as propylene glycol, glycerol, mannitol, isopropyl alcohol, sorbitol, etc.). This test should be performed within 6 hours of exposure to ensure accuracy, or it could result in a false negative. Since peak levels of ethylene glycol are detected in the first 1–6 hours after ingestion of the toxin, it is important that this test be used early during suspected poisoning. By as early as 24 hours after ingestion, insufficient ethylene glycol remains to allow detection on this blood test, but the damage to your pet’s body has already occurred.

Are there other tests that can indicate ethylene glycol poisoning?

Ethylene glycol is converted by the liver into toxic byproducts that damage the kidneys. This damage can be identified in a serum biochemistry profile. However, these tests are not specific for ethylene glycol poisoning, and by the time these blood tests show evidence of kidney failure, the prognosis is grave to poor, as it is too late to treat with the antidote. 

A urinalysis may also confirm ethylene glycol poisoning and underlying kidney damage. And lastly, a special black-light lamp (Wood’s lamp) can sometimes be used to examine the urine, muzzle, and paws of the patient to look for the presence of the warning dye that is added to automotive antifreeze.

If you suspect your dog has ingested ethylene glycol, seek immediate veterinary attention. The prognosis is very poor once clinical signs have developed. The antidote (fomepizole) is only effective if given within 8–12 hours in dogs. When in doubt, call your veterinarian or Pet Poison Helpline 24/7 at 1-800-213-6680 for life-saving assistance in managing a poisoned patient.

Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per-incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com