What is hyperthyroidism?Hyperthyroidism in cats happens when the thyroid becomes overactive, and produces an excess of thyroid hormone. The thyroid is a butterfly shaped gland which is located on either side of a cat's windpipe. This gland produces hormones that control the metabolism and organ function. According to experts, the primary reason why cats develop hyperthyroidism is due to the development of a tumor which is known as an adenoma, in their thyroid gland.

How common is hyperthyroidism in cats?
Hyperthyroidism is considered as one of the most common endocrine conditions that affect cats, especially older cats more than the age of 10. The median age for developing the condition is approximately 13 years, and there is only a small number of cats develop the condition before the age of 10. Some veterinarians estimate that there are about 2 percent of cats over 10 will acquire hyperthyroidism, and, due to various factors which may include environmental exposures.

Is hyperthyroidism dangerous?
If not treated, the condition may lead to heart or kidney failure and can be fatal. Symptoms of hyperthyroidism in cats may include weight loss, increased appetite without weight gain, diarrhea, unusual vomiting, friskiness, more frequent urination, weakness, decreased appetite or activity, and labored breathing.

Hyperthyroidism Diagnosis

Diagnosis is primarily made by blood test to measure the level of thyroxine (T4) in the cat’s blood. The high T4 levels indicate that there is hyperthyroidism. Occasionally, if results are not definite, a more definitive and costly test which is known as the Free T-4 may be conducted. In some cases, veterinarians will use other tests which include T3 levels, T3 suppression test, thyrotropin-releasing hormone stimulation test, and thyroid radionuclide uptake and imaging to confirm a hyperthyroidism diagnosis.
What are the treatment options for hyperthyroidism?
Most cat owners use the three conventional treatment options which include antithyroid drugs, surgical removal of the thyroid, and radioactive iodine treatment to stop the thyroid gland. However, some experts and practitioners also continue to develop more alternative therapies for milder forms of hyperthyroidism.
Is there a therapy for hyperthyroidism?

Many practitioners and cat owners opt a treatment which is called antithyroid therapy since the method is non-invasive and not costly. The therapy involves putting the cat on the drug called methimazole. But there is a disadvantage in using this method because it does not resolve the hyperthyroidism in some cats. In addition, some cats may experience exhaustion and vomiting as side effects.

What is involved in surgery for hyperthyroidism?
A surgery known as thyroidectomy is performed to remove the affected part of the gland. It can be an effective cure, and many vets are capable of doing this surgery. It requires only a few days of hospitalization.

Watch the video below about Hyperthyroidism in Cats.