Low Thyroid Levels in Cats

Low thyroid levels in cats is a condition also referred to as hypothyroidism. This is a condition caused by a thyroid gland deficiency. The deficiency of thyroid hormones will affect the metabolism of all tissues in the cat's body. Low thyroid levels are rarely met in felines and can be managed.

Causes of Low Thyroid Levels

The low thyroid hormone levels in your cat are most often caused by a treatment for hyperthyroidism that has slowed down the function of the thyroid glands. However, there may also be other causes for low thyroid levels such as:

  • The removal of one or both thyroid glands
  • Radioactive iodine treatment
  • A tumor affecting the thyroid glands
  • Iodine deficiency in the cat's diet
  • The treatment with certain drugs such as methimazole, which has various side effects, including the reduced production of thyroxine
  • Immune system diseases that can affect the thyroid gland's function

Symptoms of Hypothyroidism

Low levels of thyroid hormone will affect the metabolic function of the entire body. The symptoms of hypothyroidism are not necessarily visible and they are mostly non-specific. However, the cat may display symptoms such as:

  • General state of weakness
  • Weight gain, as the metabolism is slower and a lot of food is not properly metabolized, so it is deposited as fat
  • Lack of activity
  • Increased sleeping hours
  • Hypothermia, especially if the cat stays in a colder room
  • Pale gums
  • Constipation
  • Lack of appetite
  • Dry skin, excessive production of dander
  • Hair loss
  • Thinning of coat

Diagnosing Low Thyroid Levels

While in some cases the low thyroid levels can be detected by running a few tests to assess the hormonal activity of the thyroid glands. This is usually sufficient to get a clear diagnosis, but in other cases, the vet will need to perform several tests. These tests may include:

  • Blood tests or a CBC
  • Analysis of the urine
  • Chest and abdominal X-rays

The clinical signs can also help in the process of diagnosing the low thyroid levels.

Treatment Options

The treatment will depend on the causes leading to low thyroid levels.

If the cat gets methimazole causing hypothyroidism, the treatment should be discontinued or lowered.

Some cats may get supplements of thyroid hormones. The treatment can be administered for a few months or may be needed for the rest of the cat's life, especially if the cat no longer has thyroid glands.

With medication, the cat's condition should improve within the following six weeks. Follow up veterinary consultations are needed to monitor the cat's progress and to adjust the treatment, if need be.

Prevention of Low Thyroid Levels

Hypothyroidism may be prevented in some cases. If your pet gets treatment for hyperthyroidism, make sure to get regular checkups to monitor the function of the thyroid glands. Ideally, the cat should not have the thyroid glands removed, so surgery must be avoided if he has hyperthyroidism.