By Dr. Becker
The Humane Society Legislative Fund (HSLF) estimates that up to 90,000 animals are poisoned each year by antifreeze spills in driveways or garages, or from products left in open containers.
Antifreeze poisoning is one of the most common types of poisoning in pets, and typically occurs when the liquid leaks from car radiators. Cats and especially dogs are attracted to the taste of the antifreeze and will lick it off the ground. Another way dogs ingest the toxin is from the toilet bowl in homes where antifreeze is used to winterize pipes. If a cat walks through a puddle of antifreeze and then licks her paws, she can ingest enough to cause death.
A Small Amount of Antifreeze Can Cause Fatal Damage
The toxin in antifreeze is called ethylene glycol. In addition to antifreeze and engine coolant, which contains about 95 percent ethylene glycol, it can also be found in windshield wiper de-icing solutions, motor oils, hydraulic brake fluid, developing solutions used in photography, certain paints, solvents, and other industrial products.
It doesn’t take much ethylene glycol to cause fatal damage. As little as 1 tablespoon can cause acute kidney failure in dogs, and about 5 tablespoons can kill a medium sized dog. Just 1 teaspoon can be fatal to a cat. If you suspect your pet has ingested a product containing ethylene glycol, you should seek help immediately.
Three Stages of Antifreeze Poisoning
Stage 1 poisoning happens within 30 minutes to 12 hours after ingestion and symptoms are similar to those seen in alcohol poisoning, including difficulty walking (staggering or “walking drunk”), euphoria or delirium, vomiting, seizures, and excessive thirst and urination.
Stage 2 occurs within 12 to 24 hours after ingestion. Clinical signs can at this point appear to resolve, but actually severe internal damage is underway.
Stage 3 poisoning occurs in cats within 12 to 24 hours after ingestion, and in dogs, within 36 to 72 hours. During this stage, severe acute kidney failure is taking place, and symptoms can include loss of appetite, lethargy, weakness, drooling, foul breath (which is from kidney failure), vomiting, diarrhea, a rapid heart rate, depression, seizures, fainting, and coma.
Diagnosis of Ethylene Glycol Poisoning
Blood and urine tests are used to diagnose antifreeze poisoning. If kidney failure has begun, some of the tests that would have been positive at an earlier stage of poisoning could become negative.
Generally speaking, any symptomatic free-roaming dog or cat, and pets whose owners can’t rule out antifreeze ingestion should be considered potentially poisoned.
Treatment Options for Antifreeze Poisoning
The treatment for antifreeze poisoning depends on how quickly the pet receives veterinary care. If an animal is seen by a vet within the first few hours of ingestion, vomiting is induced and charcoal is given to bind any antifreeze that has traveled into the intestines.
Antifreeze becomes even more toxic as the liver breaks it down to other components. If an animal is taken to the vet soon after ingestion, a drug is given to inhibit the liver from converting the antifreeze to more noxious compounds, allowing the unprocessed antifreeze to pass into the pet’s urine.
Treatment for antifreeze poisoning must be started as soon as possible after ingestion to be effective. The quicker you get your dog or cat to the veterinarian, the better his or her chances for survival.
Sadly, most animals who don’t receive veterinary care until they’re in kidney failure will die. Occasionally, a pet in stage 3 is saved with very aggressive treatment. Some specialty veterinary practices offer dialysis that can be used to take over for the kidneys and give them a chance to repair. Whether or not dialysis is successful depends on the extent of injury to the kidneys, and unfortunately, antifreeze usually causes very severe and irreversible kidney damage. Although very rare, kidney transplants have also been performed on both dogs and cats.
Preventing Antifreeze Poisoning in Your Pet
Antifreeze poisoning can be easily avoided by following a few simple safety tips:
- Look for antifreeze products containing the safer propylene glycol rather than highly toxic ethylene glycol.
- Keep antifreeze containers tightly closed and stored out of reach of your pets.
- Dispose of empty or used antifreeze containers properly.
- Be careful not to spill antifreeze, and if you do, clean it up immediately. Check your car radiator regularly and repair leaks right away.
- Don’t let your pet roam unsupervised where he may have access to antifreeze.
Fortunately, U.S. manufacturers of antifreeze and engine coolants recently agreed to voluntarily begin adding bittering agents to their products to discourage pets, children, and wildlife from sampling the sweet-tasting liquid. Manufacturers are adding bitter-tasting denatonium benzoate to antifreeze and coolant products sold throughout the U.S.