Ethylene Glycol

What is Ethylene Glycol Toxicity?

Ethylene glycol is a type of alcohol most commonly found in engine antifreeze. Dogs and cats find the sweet taste acceptable and consume it readily. The ingestion of even small amounts can be deadly.

Because ethylene glycol is an alcohol, the first stage symptoms appear as central nervous system signs. An animal may appear to be drunk (altered mentation, weakness and decreased motor control). These symptoms can appear within 30 minutes and usually peak between 6 and 12 hours after ingestion. Stage II is seen more in people than animals, usually 12 to 24 hours after ingestion. Signs include increased heart and respiratory rates, mild hypertension, decreased blood oxygen levels, pulmonary edema and heart failure. Stage III, acute renal failure, usually occurs 24 to 72 hours after ingestion.

Ethylene glycol is rapidly absorbed from the gastrointestinal tract. Around 50% is rapidly metabolized in the liver into extremely toxic compounds. These compounds cause severe metabolic problems and form crystals inside kidney cells. The crystals destroy the cells that help filter and concentrate the urine. When these cells die, the kidneys can no longer complete their vital function of filtering waste products from the blood. The result is the rapid build up of these wastes in the blood.

There are four basic principles of treatment. The first is to remove the ethylene glycol before and after absorption. The second is to prevent the metabolism of the ethylene glycol into the toxic metabolites. The third is to prevent formation of the crystals. The last is to provide nutrition and general support over this time. Treatment and monitoring is intensive and best provided at a 24-hour facility.

The mortality rate is very high. Unless there is a known exposure, it can be very difficult to diagnose. By the time clinical signs of renal disease are apparent, therapy may no longer be effective. The prognosis is considered grave. The best opportunity to treat successfully is immediately after known exposure. Even if the acute stage is survived, the damage to the kidneys may be too severe for the patient to survive.

Veterinarians tend to see a slight seasonality to ethylene glycol poisoning. More cases tend to present in the fall as people change the antifreeze in their vehicles in preparation for winter.

The best advice, do not allow animals access to ethylene glycol. Do not allow animals to be around when changing the antifreeze. Properly dispose of the antifreeze immediately. If this is not possible, place the antifreeze in a sealed container away from animals (and children). Clean up any spills immediately. Even a small amount on the garage floor can be deadly.

[Go Back]