Samantha Taylor, FAB resident at Bristol Veterinary School, reports on a wintry tale with a happy ending 
Spirit (pictured right) is a much loved family pet but by the age of 18 months he already had a history of getting into scrapes! At the age of six months, he swallowed a toy and had surgery to remove it from his intestines. He had also been treated for inflammatory bowel disease with a special diet.
So, one night when Spirit vomited after sneakily eating the dog's food, his owner didn't worry too much. However, by the following day he had become depressed, refused food and was still vomiting. At the local veterinary surgery (where he was well known!) he was put on a drip and blood samples were taken. By the time the blood results were available, Spirit had deteriorated to the point where he was barely conscious. The results suggested that Spirit's kidneys were failing and he was referred to us at The Feline Centre at Bristol University for intensive treatment.
Calcium oxalate crystals in Spirit's urine suggesting anti-freeze poisoning |
Spirit arrived at Bristol unconscious and hardly responding to stimulation at all. He was rushed to the intensive care unit and blood results showed severe kidney failure. But why would a young, healthy cat suddenly develop kidney failure? The most likely reason would be poisoning and, given the recent cold weather, anti-freeze toxicity was a concern. Although Spirit's owners never used anti-freeze he had access outdoors where he could have been exposed. Suspicions were confirmed when urine samples showed the presence of calciumoxalate crystals and the calcium levels in Spirit's blood were low.
Anti-freeze or ethylene glycol, is a chemical used in car engines and as a de-icer in brake fluids and other liquids. It is sweet tasting and therefore attractive to pets, often dogs and occasionally cats. The ethylene glycol is broken down into toxic products which cause neurological, gastrointestinal and kidney problems. Initially the ethylene glycol causes the animal to appear drunk with drowsiness, even seizures and depression. Irritation of the stomach can cause vomiting. After 24 hours the toxic products bind with calcium in the blood and the resulting chemical is deposited in the kidneys, causing severe kidney damage and acute kidney failure. Some calcium crystals end up in the urine. Spirit's low blood calcium and crystals in the urine were consistent with anti-freeze toxicity. If animals are treated soon after ingesting the anti-freeze, an antidote can be administered. Although it sounds odd, this treatment is alcohol (medical ethanol) as this blocks the production of the toxin products. It must be given cautiously, at the correct dose and rate by a veterinarian, and the animal must be closely monitored.
Spirit was immediately treated for his kidney failure with fluid therapy directly into his veins. We monitored how much urine he was producing with a urinary catheter and as this was less than the fluid we were putting into his body, he was at risk of 'fluid overload' and resultant fluid on the lungs. Therefore we treated him with diuretics to improve urine output. The ethylene glycol, kidney failure and the treatment had caused multiple abnormalities in Spirit's blood electrolyte levels and made his blood very acidic. These problems were treated, Spirit was constantly monitored and adjustments to the fluid therapy and medication were made as required. Spirit remained unconscious and his owners were told it was unlikely he would recover as the prognosis for cats with kidney failure caused by ethylene glycol is very poor. In Spirit's case as it was at least 24 to 36 hours after he had ingested the toxin and he had already developed kidney failure, there was no benefit in administering ethanol and his only hope was treatment for acute kidney failure.
The following day Spirit's blood results showed some improvement and he was responding to stimulation. However, we didn't want to get our hopes up as he was still very unwell and the damage to his kidneys may have been permanent. The intravenous fluids were continued and we monitored Spirit's urine output and blood results closely over the next 48 hours.
Thankfully, over the next four days Spirit made a remarkable recovery. His blood results improved and we slowly reduced the fluid therapy and Spirit began to eat. We knew he was better when he sank his teeth into my arm! I have never been so pleased to be bitten (Spirit had a reputation that lived up to his name!). Spirit was discharged after one week of treatment and his kidneys show no sign of permanent damage. He still tries to steal the dog's food but they remain good friends and his owners don't mind at all as they were so close to losing him.
Acute kidney failure can be caused by various toxins including plants (lilies in particular), foods such as raisins and grapes, drugs (some antibiotics and pain killers) and, as in this case, anti-freeze. We do not know how Spirit got hold of the ethylene glycol but there was a suspicion that people use the product in garden water features to prevent them freezing. Many people are not aware just how toxic ethylene glycol is to all animals, including humans, and so all of us must make sure it is securely stored and any leaks from car engines are cleaned up immediately.
Thankfully Spirit recovered from his kidney failure - we're not quite sure how many lives he has left but he's living each one to the full!
July 2009 |
