Neurologist advises on thiamine deficiency in cats

Following Pets at Home’s  recall of some of its dry cat food products, Laurent Garosi, European Veterinary Specialist in Neurology at Davies Veterinary Specialists, has shared knowledge and advice on thiamine deficiency with vet practices and owners at

The practice says that thiamine deficiency in cats is generally rare, so the number of recent cases seen in the UK has been a cause for concern amongst vets. Symptoms may include severe weight loss or anorexia, vomiting, impaired vision, dilated pupils, tremors and seizures. Prompt treatment is needed, usually in the form of thiamine injections, an oral supplement and an immediate change of food as a precaution.

Laurent Garosi said: “In 20 years I have only seen a handful of cases. My concern is that there may be many more cats out there in need of a diagnosis, which is why we are building awareness and supporting our referring vets in the diagnosis of this condition.”

More detailed information has also been sent direct to DVS’s referring veterinary colleagues to help them with prompt diagnosis and treatment:

What are the signs of thiamine deficiency in cats? 

Initially most cats will show anorexia and some degree of vomiting preceding neurological signs. The latter include fairly rapid onset of impaired vision, dilated pupils, ataxia, vestibular signs, tremors and seizures.

How do you diagnose thiamine deficiency? 

It is based on a combination of factors: clinical presentation, MRI findings, which are fairly typical (although not pathognomonic) and response to thiamine supplementation.  Absolute confirmation is technically difficult and not widely available: direct measurement of thiamine in the blood may not reflect deficiency, as this is not a good reflection of tissue concentration of Thiamine.  Indirect methods are functional tests looking at effects of thiamine or lack of it: demonstration of reduced transketolase activity in red blood cells which is not readily available for most veterinary practices, or other indirect methods such measuring abnormal metabolites such as organic acids in the urine.

What are the causes of thiamine deficiency in dogs and cats? 

There are three main causes: 1) inability to absorb thiamine due to gastro-intestinal disease, 2) inability to process thiamine due to liver disease and 3) decrease level of thiamine in food.  The latter can be caused by the heating process used for food preparation (thiamine is destroyed by heat), addition of sulphur dioxide or sulphite preservatives to meat which inactivate thiamine and feeding food rich in thiaminase activity such as some raw fish.  Therefore all-raw fish diet in cats can be a cause of thiamine deficiency.

What should you do if you suspect you have a cat with thiamine deficiency and whose diet consists of a product being recalled? 

Unless the cat is showing neurological signs, the first step is to stop the diet and switch to another diet not listed in the recall.  Thiamine supplementation (intramuscular injection) is advised in the first instance in a case with compatible neurological signs.  Other causes for the neurological signs must be considered in the case of failing to respond to Thiamine injections within 24-48 hours.

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