Thiamine Deficiency in Cats

What is thiamine deficiency and is it common?

Thiamine deficiency used to be a common condition due to the fact that in days gone by, raw fish was a common component of a cat’s diet. Raw fish contains an enzyme called thiaminase and this enzyme destroyed the thiamine (or vitamin B1) in the food. However, commercial manufacturers realized this problem and foods were fortified with thiamine and the disease was rarely seen.

The disease has re-emerged due to the use of “pet meat rolls” which are preserved through the addition of sulpur dioxide or sulphites. These agents delay spoilage by inhibiting oxidation of myoglobin and preserve the red colour of meat. However, the sulphur preservatives also destroy the thiamine within the meat and this results in a thiamine deficiency. A level of 400mg of sulphur dioxide per kilogram destroys 55% of the thiamine in the food whilst 1000mg of sulphur dioxide per kilogram destroys 95% of the thiamine.

What are the signs of thiamine deficiency poisoning?

Thiamine is essential to energy production pathways and these energy pathways are especially important in the brain and central nervous system. Once these energy pathways are affected lactic acid is built up in the brain in the same way as an athlete gets a “stitch” when running and not getting enough oxygen. Damage occurs to the vital areas of the nervous system due to bleeding and death of the tissue. Clinical signs include mental dullness, wobbliness, weakness and seizuring (fitting). Occasionally other signs can occur in cats such as dilated and poorly responsive pupils and a weak hanging head. Unfortunately, unless prompt attention is given to your pet, thiamine deficiency can be fatal.  

"Thiamine is essential to energy production pathways and these energy pathways are especially important in the brain and central nervous system. Once these energy pathways are affected lactic acid is built up in the brain in the same way as an athlete gets a “stitch” when running and not getting enough oxygen."

What can I do?

The safest action is to ring your veterinarian for advice. If your cat is showing any signs it is best to make an appointment to see your veterinarian. If you unsure of your pet’s diet, please bring along the packaging to your veterinarian who will be able to advise whether the diet is likely to cause thiamine deficiency. Check labels of any food and make sure that there are no preservatives (preservative 220, 221, 223, 224, 225 and 228). Avoid cooked non refrigerated pet food rolls and processed meats such as spiced sausages

What can the veterinarian do?

On arrival the veterinarian will assess your pet. Your veterinarian will usually give injections of thiamine if they are suspicious of thiamine deficiency. It is quite difficult to diagnose this disease and given that thiamine supplementation is cheap and simple, often trial treatment is the best means to diagnose the condition. Other tests may be required to exclude other diseases that may cause similar signs. An MRI may show some signs that are very suggestive of the deficiency. If seizuring (fitting) is occurring, your veterinarian may give some sedatives such as valium or anti-convulsives and may also keep you pet anaesthetized for as long as necessary until the seizures can be controlled.

What can I do to prevent thiamine deficiency?

Your veterinarian will discuss these options with you. As discussed, it is best to avoid non refrigerated meats and pet food rolls. This is especially true in younger cats which may have an increased need for thiamine.

Is there anything else I need to know?

There are many other causes of the signs that this deficiency can cause and whilst it is important to be aware of this condition, your veterinarian will assess the various other causes of these signs and the likelihood of this deficiency being responsible.