Ethylene Glycol Poisoning in Cats

Overview:

Ethylene glycol is a common cause of poisoning in cats & a leading cause of acute kidney failure. It is a clear, odourless liquid with a sweet taste which is attractive to cats, dogs & children. It is most commonly found in antifreeze, but is also in many other products (see end of article).

Once ingested the body starts to break down the ethylene glycol quickly. Around 50% of the ethylene glycol is excreted by the kidneys, the remainder is metabolised by the body into other toxins including glycolate, glycoaldehyde, glyoxylate & oxalate. The oxalate combines with calcium to form calcium oxalate crystals inside the renal (kidney) tubular cells, causing blockage & renal epithelial necrosis.

While ethylene glycol is relatively non toxic,  the metabolism causes by products which are highly toxic to the cat. Even as little as a teaspoon or two is enough to kill a cat & ingestion of ethylene glycol is always a medical emergency, and you should take your cat to the veterinarian immediately.

What are the symptoms of antifreeze poisoning in cats?

There are three stages to poisoning. [1]

1) CNS Depression Phase - Ethylene glycol is rapidly absorbed from the gastrointestinal tract. Within 30 minutes to 12 hours of ingestion the cat show the following symptoms:

• The cat will appear intoxicated, stumbling, lack of coordination, dizziness & vomiting.

• Excessive thirst.

• Excessive urination.

• Seizures

• Vomiting

These symptoms last for approximately 12 hours after ingestion. After this, the cat may appear to recover.

2) Cardiopulmonary Toxicity Phase - Approximately 12 - 24 hours after ingestion the following symptoms appear:

• Tachypnea (rapid breathing)

• Tachycardia (rapid heart rate)

• Metabolic acidosis (the blood is too acidic)

• Hypertension

• Lethargy

• Anorexia

3) Renal Toxicity Phase

• Kidney failure

• Vomiting

• Depression

• Coma

How is antifreeze poisoning in cats diagnosed?

Your veterinarian will take a history from you, including possible exposure to ethylene glycol. He will perform a physical examination of the cat.

A commercial test kit is available for rapid identification of ethylene glycol in whole blood.

Urinalysis: To detect the presence of calcium oxalate crystals in the urine & asses kidney damage.

Blood Gas: To detect the extent of acidosis.

Ultrasound is performed to view the kidneys & evaluate the extent of damage to the kidneys.

Serum biochemistry  to detect low blood calcium, as a result of calcium oxalate formation which depletes calcium levels (hypocalcemia).

Some antifreeze products contains the colourant fluorescein, which helps detect radiator leaks. This can cause the cat's urine to glow a bright green colour when viewed under a woods lamp. However, not all ethylene glycol products contain fluorescein, so the absence of this doesn't necessarily rule out poisoning.

How is antifreeze poisoning treated?

Successful treatment requires diagnosis & the prognosis is always guarded. If treatment is not begun within 6 hours of ingestion, prognosis is grave. [2]

Treatment is firstly aimed at blocking or decreasing absorption ethylene glycol & preventing the formation of toxic metabolites, removal of the toxin & treatment of the severe metabolic acidosis.  This includes;

• Induce vomiting, lavage stomach (washing out the stomach with sterile water or a saltwater solution) or both.

• Administration of ethanol. This drug should be administered as soon as diagnosis is made.

• Sodium bicarbonate is administered to counter the metabolic acidosis.

• Supportive treatment to include correction of fluid & electrolyte imbalances.

What other products contain Ethylene glycol?

Photographic developing fluid, hydraulic brake fluid, some cosmetics, some plants, radiator coolant, decorative snow globes, air conditioning coolant.

References:

[1] C-Tech Corporation

[2] The Feline Patient - Gary D. Norsworthy, Mitchell A. Crystal, Sharon K. Fooshee, Larry P. Tilley.

Please note:

The medical articles on this site have not been written by a veterinarian & should not be considered a replacement for a veterinarian visit. The articles are provided for informative purposes only.

Always seek immediate veterinary advice for any problems (health or behavioral) in your pets. 

While great care has been made in the creation of these articles, we cannot guarantee the accuracy or omissions on these pages. If in any doubt whatsoever, seek professional medical advice.