Cat Thyroid Problems

Cat Thyroid

The thyroid glands are located on each side of the cat’s neck, and produce hormones which help to regulate the body’s metabolism. Any changes in the output from these glands can have widespread effects in the body. It is difficult to detect thyroid gland problems in the early stages because the symptoms are unlikely to be specific. Initially, the obvious signs are more likely to relate to the changes in hormonal output, than to the glands themselves.

Cat ThyroidA sign of one of the types of thyroid problem in cats — hypothyroidism — is weight gain. Cats will also be more sensitive to the cold. However, a blood test will determine the exact nature of the problem.

Q. How can my vet confirm whether my cat has a thyroid problem?

By means of a blood test which allows the level of thyroid hormones to be checked. Subsequent monitoring enables the progress of treatment to be assessed.

The two major types of thyroid problems are hypothyroidism and hyperthyroidism.


There can be a fall-off in the output of thyroxine and similar hormones produced from the thyroid glands. This condition is known as hypothyroidism. It is likely to result in a cat putting on weight in the initial stages, with affected individuals also seeming to feel the cold more than usual. One of the clearest indicators of a thyroid involvement is, however, when the skin becomes more scaly than usual, though this happens in the later stages of illness.


In other cases, when the output from the thyroid glands is increased, then this is known as hyperthyroidism. In the beginning, an affected cat will lose weight, although its appetite will be increased. It is also likely to drink more than usual. These signs are likely to be linked with vomiting and diarrhoea, and before long, the thyroid glands themselves will increase in size, possibly to the extent of pressing on the cat’s windpipe and so affecting its breathing. Hyperthyroidism is most commonly encountered in cats from middle age onwards, and is frequently the result of a tumour affecting the glands.

Cats kept on a diet deficient in iodine will ultimately develop hypothyroidism. This is known as goitre, but it is very rare today, thanks to formulated foods which contain sufficient quantities of this trace element.

An excessive output of thyroid hormones, as occurs in hyperthyroidism, can cause enlargement of the heart and cardiac failure if left untreated.

Kelp powder, a form of dried seaweed, is a natural source of iodine. It can be sprinkled over wet food, to which it will stick readily.

The thyroid glands are beside the windpipe; the tiny parathyroid glands are next to them. They produce a hormone regulating the body’s calcium stores.

Q. Can hyperthyroidism in a cat be treated?

It may be possible to operate and remove the glands where the tumour is present. Alternatively, an affected cat can be dosed with radioactive iodine, which is picked up by the thyroid glands and then kills off the tumour. Medication is also available to block hormone production.

Q. How can a vet help a cat with hypothyroidism?

This means giving tablets regularly to make up for the deficiency of these hormones. The response to treatment is usually good.