MVVS Blog

Feline Hyperthyroidism

By June 30, 2021No Comments

There is a rather common illness that “middle-aged” cats can develop… hyperthyroidism. Feline hyperthyroidism can be compared to a running competition for a cat. The overproduction of thyroid horomone makes the cat’s body respond as if they are running a constant marathon at a sprint. Increased heart rate, losing weight but having a wonderful appetite, lack of grooming vomiting and/or diarrhea are the typical signs. However, other cats can become hyper excitable or extremely talkative and have an increase in thirst and urination. A physical exam will be the first step in diagnosis of hyperthryoidism. The veterinarian will make note of the body condition score (which should be 4-5 out of 9), the condition of the coat and if the cat has an enlarged thyroid gland (located near the throat).

Hyperthyroidism can cause problems with the heart as well. The veterinarian will be able to listen for abnormal heart rhythms or sounds. They can evaluate the heart rate. The veterinarian may request bloodwork to confirm if the cat has hyperthyroidism. If the thyroid gland is producing too much T4 hormone, it will show an increase level in their bloodwork. There is the chance that the cat is in the early stages of the illness and shows a normal T4 level – this may require the cat to have a more specialized thyroid test performed. There are a couple different options to treat hyperthyroidism in cats. Some cats do well on a prescription Hill’s Y/D diet, but the owner must be hyper vigilant to make sure the proper amount of food is being fed and that the cat doesn’t get any other types of foods or treats. Most cats need to take an oral medication that controls the production of the thyroid hormone. These chosen forms of treatment will require repeat blood screening in 4-6 weeks after treatment has started. Routine monitoring of blood levels will be necessary to ensure that the diet or medication is keeping the thyroid hormone levels regulated. Radioactive iodine treatment is a more permanent resolution of feline hyperthyroidism.

This procedure, performed at a referral clinic, will selectively destroy the overactive thyroid tissue. This treatment is done by a specialist. Once a cat has a stabilized T4 level, annual bloodwork is done to make sure that treatment levels are still working properly. If left untreated, the blood pressure will increase, the kidneys will begin to fail, eye sight can be affected and ultimately death will occur.

This manageable illness may sound intimidating but uncontrolled feline hyperthyroidism can be far more scary.

Happy July 4th!

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