Ethylene glycol is the active ingredient in antifreeze, which is used in the cooling systems of automobiles. It is also found in hydraulic fluid, solar collectors, automotive brake fluid, and liquid rust inhibitors. Ethylene glycol is toxic to all creatures, including humans. However, it is typically dogs and cats that account for the majority of cases of antifreeze poisonings. In fact, it is the most common cause of poisonings of dogs and cats in the United States. It only takes one to two teaspoons of ethylene glycol to poison a cat, and about three tablespoons to kill a medium size dog.
The reason that animals ingest antifreeze is because it is sweet and tastes good to them. If antifreeze leaks on the ground or is left in a container, following a flushing of a cooling system, pets will actively seek it out. This is why it is extremely important to hose off any puddles on the ground that may have leaked from a vehicle, and properly dispose of old coolant if you flush your own radiator. Antifreeze can be easily recognized because it is a translucent bright green color.
Ethylene glycol has both immediate and long-term affects on the body. Once consumed, it is quickly absorbed and metabolized by the body. Peak blood concentrations occur within three hours of ingestion. Within the first thirty minutes after drinking it, your pet will appear ataxic or intoxicated. This intoxicated stage can last for up to six hours. Eventually, the drunken behavior will end, and it will appear that everything is normal, again. However, this is not the case, because the ethylene glycol enters the animal’s kidneys and liver where it is oxidized into toxic compounds that acidify the blood and destroy renal cells in the animal’s kidneys. Once the kidneys are damaged, they are no longer able to cleanse the body of waste. The transformation of antifreeze changes from glycoaldehyde to glyocolic acid, and oxalate. It is the glycolic acid and oxalate that are the main causes of kidney damage and resulting uremia. These chemicals can also cause serious damage to the central nervous system. There is no treatment that can reverse this damage. This type of damage can even be fatal within a few days.
Early signs of antifreeze ingestion are similar to alcohol intoxication. It is also common for dogs and cats to vomit, as ethylene glycol is quite irritating to the stomach. The animals will typically drink and have to urinate excessively and may seem wobbly and depressed. After the intoxication stage wears off, the animal will likely seem much improved. However, the next day (in cats), or two days later (in dogs), patients normally become much sicker. They may become weak, depressed, and dehydrated. They may also develop mouth ulcers, diarrhea, rapid breathing , and seizures. Also. their kidneys are frequently swollen and painful.
It is only possible to save the animal when the poisoning is discovered prior to the occurrence of kidney damage. It is much easier to identify antifreeze poisoning when the animal is in the stage where staggering and intoxicated behavior are present. It is considerably more difficult to identify once the ethylene glycol has reached the liver, because in the early stages of this phase, the animal will appear healthy, while later in this phase, the symptoms are multisystemic and nonspecific. These later symptoms can be confused with other diseases, like diabetes, pancreatitis, gastoenteritis, or other forms of kidney disease. Once the ethylene glycol metabolites have attacked the kidneys, it is too late to provide a cure.
The amount of antifreeze consumed by the animal is crucial in determining the success of treatment. Animals that have ingested a large quantity of antifreeze will not respond favorably to any type of treatment. The purpose of treatment is to decrease the amount of absorption of the ethylene glycol in the stomach and intestines, and increase the amount of excretion through the kidneys. Preventing the metabolism of ethylene glycol to glycolic acid and calcium oxylate, as well as correcting the acidosis of the blood are extremely important to the recovery of the animal.
The steps that your veterinarian will take are as follows:
1. Administer either hydrogen peroxide or apomorphine to get the animal to vomit any of the poison that may still be in the stomach.
2. Give the animal water in order to thoroughly rinse out the stomach.
3. Administer activated charcoal to absorb any remaining poison.
4. Administer large amounts of intravenous saline to increase the animal’s urine production, in an effort to get the animal to excrete out as much ethylene glycol as possible.
5. Give the pet 2.5 ml of 20% (40 proof) ethanol per pound of body weight diluted in IV fluids. This is given as a slow drip over the course of six hours for five treatments, then over the course of eight hours for four additional treatments. At the same time, sodium bicarbonate is also given to reduce the acidity of the blood. The amount of sodium bicarbonate to give will be determined based on the level of acidity of the animal’s urine.