Roni Holewinski, CVT

Industry Representative

Antifreeze poisoning is commonly encountered in veterinary clinics every winter. While there may be a variety of different “antifreezes” used in today’s automotive antifreeze products, ethylene glycol poses the greatest risk to pets and is what we’re discussing in this post. Ethylene glycol is so dangerous that just 2 teaspoons of the liquid is lethal for a cat and a couple tablespoons can kill a medium sized dog. It is sweet smelling and some animals will not hesitate to lap it right up off of the garage floor. It is important to know the warning signs and treatment protocol for ethylene glycol poisoning. It is also very interesting that the antidote for ethylene glycol toxicity can include clear hard liquors, such as vodka or Everclear®. That’s right… your veterinarian may just have to get Fido a bit tipsy.

Clinical Signs

It is important to recognize the signs that accompany ethylene glycol poisoning with your dog or cat. Within 30 minutes of ingestion, they may resemble a person who has had too much to alcohol drink. Incoordination, excessive urination, excessive thirst, vomiting, and lethargy are amongst the first signs to appear. Within 24 hours, some animals show apparent improvement which may prevent pet owners from realizing that their pet is in real danger. Unfortunately, during this time of “improvement”, the animal is starting to suffer internal organ damage—specifically to the kidneys. Additionally, their breathing and heart rate will elevate, they may develop acidosis (the pH of their blood decreases), and dehydration typically sets in. The final stage of toxicity includes lethargy, anorexia, seizures, coma, depression, and severe kidney dysfunction (which cause the animal to be unable to produce urine). The final symptom is death. Without medical treatment, your pet may perish.

Diagnosis

Hundreds of pets die every winter from antifreeze toxicity and many may go undiagnosed. The clinical signs are common to other medical conditions and can also occur following exposure to other poisons, chemicals, and/or drugs. Treatment for ethylene glycol toxicity is very specific and needs to be started as soon as a diagnosis is made or strongly suspected. Testing a pet for ethylene glycol can be tricky. Blood tests can be difficult to interpret and must occur within 8-12 hours of ingestion in order to provide a reliable result. Another way to detect ethylene glycol toxicity is by examination of the urine. Calcium oxalate crystals, shed by the kidney, can be observed in the urine after ethylene glycol ingestion. These unique crystals are typically only observed in a urinalysis with this sort of toxic exposure.

Treatment

If your pet ingested ethylene glycol antifreeze recently enough, the one of the first steps in treatment may be to induce vomiting, provided the pet is not yet suffering neurological impairment. The next most critical step is to start the antidote. Timely intervention is critical because if the antidote is delayed more than 3 hours after exposure in cats or 8 hours in dogs, the prognosis is poor.

The two antidotes for ethylene glycol poisonings are 1) a medication called fomepizole or 2) ethanol, the type of alcohol found in alcoholic drinks. Commercially made pharmaceutical antidotes (i.e., fomepizole) are the preferred treatment choice; however, this drug can be expensive and some veterinary hospitals do not carry it. Because of its low cost and ease of availability, alcohol (ethanol) is the antidote of choice for some veterinarians. Both antidotes work the same way by blocking the formation of ethylene glycol’s toxic metabolites that lead to acidosis and kidney damage. Hard liquors, including vodka and Everclear®, when delivered intravenously, can save your pet’s life. Your pet will have to be hospitalized during the treatment process because…well…he is going to be very drunk…but if caught in time, treatment is usually very successful. The alcohol dosage for a medium sized dog is equivalent to approximately 8 shots of vodka every 4-6 hours and you can expect to see the consequences of alcohol intoxication. Pets need to be monitored during this alcohol treatment cycle…to make sure they don’t make bad decisions or bark up the wrong tree.

With timely treatment, prognosis is good. Just make sure you have a pot of coffee on and a cozy place to let your pet sleep it off once you arrive at home.

If you suspect your pet may have ingested antifreeze, it is extremely important to seek emergency care as soon as possible. Without treatment, your pet is in very real danger of dying.