Antifreeze poisoning in cats
During the winter we try to prevent freezing by using ethylene glycol, otherwise known as antifreeze, in car radiators and in some screen washes and de-icers. Every year many cats die because they have been poisoned by this chemical. Prompt treatment is the only way for cats to survive poisoning with ethylene glycol.
How are cats exposed to ethylene glycol?
Dogs and children are said to be attracted by ethylene glycol’s sweet taste. Cats do not taste ‘sweetness’ in the same way, but it does appear to be attractive to cats for some reason. Cats only need to drink a teaspoon or less of antifreeze for it to cause serious illness and even death. So a curious lick or two from a bottle, or from a spillage, could be enough to cause big problems for the cat. Antifreeze tends to be found in garages or on drives, where it may be stored incorrectly or spilled while pouring into a car radiator, or it could be left in a shallow tray after a car radiator has been drained. A cat walking through a puddle of antifreeze will groom its coat or paws and ingest the poison this way. Ethylene glycol may also be used in garden water features to prevent them freezing up, and unfortunately this can also be drunk by a thirsty cat. Regrettably, malicious poisonings have been reported, when individuals deliberately poison cats (and other exposed wildlife) and these stories feature all too often in the press. In many countries, deliberate poisoning of cats is a criminal offence.
How does ethylene glycol harm cats?
Ethylene glycol is broken down in the liver and this process produces other chemicals that severely damage the cat’s kidneys. This damage is often so severe that the cat cannot survive.
What signs of poisoning do cats show?
A cat may not show any signs of poisoning for about half an hour after ingesting ethylene glycol. It may then start to show signs such as sickness, a wobbly gait (appearing ‘drunk’), weakness and tiredness. As kidney damage develops, cats may also drink and urinate a lot and become very unwell, even collapsing. Blood and urine samples taken by the vet will show abnormalities consistent with ethylene glycol toxicity such as kidney damage and certain crystals in the urine.
How is ethylene glycol toxicity treated?
If a cat is treated by a vet within an hour of drinking antifreeze it may be made to vomit to try and stop the cat absorbing the chemical from its digestive system. Unfortunately cats are rarely seen drinking the antifreeze and are usually taken to the vet when the antifreeze has already been absorbed and the cat is showing signs of illness. If the cat can reach the vet within 3 to 4 hours of ingesting the ethylene glycol, it may be treated with an antidote or a drug that can counteract the effects of the poison. The most commonly used antidote in cats is ethanol (alcohol), frequently in the form of vodka. This sounds strange but the ethanol stops the poison being broken down in the cat’s body into the more toxic forms that cause kidney damage. This treatment unfortunately doesn’t work if the cat has already developed kidney damage. Therefore, going to the vet immediately if you think your cat has been poisoned is extremely important.
How can I prevent my cat being poisoned with ethylene glycol?
If you have any products containing ethylene glycol such as antifreeze, make sure you store them safely away from children and animals. Use screen wash and de-icer sprays that do not contain ethylene glycol. If a car radiator has been drained and a splash of antifreeze remains on the floor, wipe it up completely and rinse the area thoroughly with water. Remember even a tiny amount on a cat’s feet (picked up if it walks through a spillage) is enough to harm it. If you think your cat has been exposed at all, on the coat or feet or by lapping up water containing ethylene glycol, contact your vet immediately. If your vet has any worries over the treatment of your cat he or she may contact the Veterinary Poisons Information Service who will advise on what treatment would be best for this situation.
Being aware of your cat’s normal health and behaviour will help you to notice signs of illness and seek treatment from your vet straight away. For example if a normally healthy cat with outdoor access returns home and seems too quiet and is sick, and if you think there is any possible chance it has been exposed to ethylene glycol, seek advice from your veterinary practice immediately.
Are there alternatives to ethylene glycol?
Unfortunately, ethylene glycol is almost universally used as an antifreeze agent, despite being so toxic, and there are few alternatives. It is possible to obtain propylene glycol based antifreeze in some regions, and this represents a safer alternative (although more expensive and still not completely safe).
Adding agents that taste bitter
It has been suggested that all antifreeze solutions should contain an additive, such as Bitrex®, or denatonium. Denatonium is a safe chemical that is said to be the most bitter tasting chemical known and can be added to potentially poisonous substances to make it less likely that they will be eaten or drunk.
While this sounds like an ideal solution to the problem of cats and other animals drinking ethylene glycol, in fact denatonium (or Bitrx®) has not been shown to be very effective in discouraging dogs from eating palatable foods and, in people, adding denatonium to antifreeze solutions has apparently not decreased the frequency of poisoning among young children. Thus while adding denatonium to antifreeze will do no harm, it may well not have the desired effect in preventing animals drinking or licking the solution.
The best advice therefore is to be highly vigilant and to prevent animals and children coming into contact with ethylene glycol, and if they do, to get them treated as soon as possible.
Unfortunately many cats poisoned with antifreeze do not survive. Laura Slinger is a veterinary nurse in the UK and tells us about her cat Scarlet.
‘As a veterinary nurse antifreeze or ethylene glycol poisoning is unfortunately something I see far too often, mainly in cats. Over the past 14 years of my nursing career, it’s one of the worst conditions I have come across. By a strange and cruel twist of fate, my own cat, Scarlet, who I had hand-reared from 2 days old, was recently poisoned. Outside it was 18 degrees. In the winter, accidental spillage and incorrect disposal of the fluid is commonplace, but in the warmer months, I cannot understand how she was exposed and always fear it was a malicious poisoning.
Scarlet’s story is the same as many of the cats I’ve treated with this condition; she went missing and then was found emaciated, dehydrated, freezing cold and collapsed. Scarlet had crawled her way almost home – she was found 100 yards away, 5 days after she went missing. I think she may have become disorientated after drinking the antifreeze and couldn’t find her way home. She had been salivating for some time and her mouth was sore and sticky – another sign of vomiting or chemical ingestion. Unfortunately, as soon as I saw her, I feared the worst – I couldn’t believe this had happened to my own cat – you never think the bad things happen to you; it’s just something you read or hear about.’
‘I rushed Scarlet to the vets closest to me and waited an agonising 20 minutes for the blood machine to process her sample and tell me how poorly she was. The minutes felt like years and I wrapped Scarlett up in a blanket and left her in her cage at the vets, trying not to move her and make her feel even worse. Scarlett’s results indicated severe kidney damage and the vet found other indications of ethylene glycol poisoning. I made the heart-breaking decision to put my darling to sleep straight away. I didn’t want to have her go through one more hour of the hell she had already gone through for up to 5 days. My friends and colleagues were all there at the end, all feeling my pain as they knew Scarlet and how much she meant to me.
Please, please dispose of antifreeze products responsibly. Never leave bottles where cats can get them in the shed/garage and clear up all spills immediately.’
In loving memory of Scarlet, the most beautiful tortie there ever was.
Spirit was an 18 month old tabby cat who lived next to a house with a water feature. In the winter it kept freezing up, so the neighbours’ solution was to put antifreeze into the water. One day, a few hours after Spirit had come in for his tea, his owners noticed that he had been sick and was looking a little strange, walking like he was drunk and not rushing over to greet them as usual. When he was sick again they took him to their local vet. The vet found signs of early kidney damage and antifreeze poisoning was suspected. He was referred to a specialist hospital as an emergency. After a difficult night and day when he remained very unwell, he showed some signs of improvement and recovery. Thankfully he recovered well enough to go home a few days later.
Spirit was lucky. He only survived because the antifreeze he drank was very diluted in the water, and because of his owners’ quick action in seeing veterinary help.
Has your cat ever been poisoned?
Costa a beautiful rescue cat under 1 year old died as a result of antifreeze poisoning in July 2013.
She came in from a very brief morning patrol of her territory and looked very wobbly, almost drunk. She had clearly been sick outside the back door as well. Being a veterinary nurse I have had the unpleasant experience of unsuccessfully nursing these poisoning cases on many occasions.
I contacted the nearest veterinary practice (not wanting to delay treatment for the additional time it would take to get her to the practice I was working at) and arranged to take her straight in. Unfortunately by the time we reached the surgery which was only 5 minutes away, she was having a fit and the sad decision was made to put her to sleep immediately.
Bearing in mind she was only outside for approx 5 mins & 15mins later was euthanased, it just shows how very toxic this substance is. I have in 30 years of nursing never had a cat recover from antifreeze poisoning, even with aggressive treatment immediately after ingestion.
Thanks to Amanda Disney for submitted her story.