Cats, like humans and all other mammals, have a double-lobed gland in the neck area called the thyroid gland, which regulates their metabolic rate. In cats, the condition of hyperthyroidism occurs when the thyroid gland develops a tumor (98% are benign) that causes the production of too much thyroid hormone (thus the term "hyper" thyroidism). Although first documented only 27 years ago by Dr. Mark Peterson, founder of Hypurrcat, hyperthyroidism has become the most common hormonal (endocrine) disorder diagnosed in domestic cats.

In cats with hyperthyroidism, excessive thyroid hormone in the blood stream speeds up most chemical reactions in the body, causing multiple clinical signs. These signs include weight loss despite an increased appetite, nervousness or increased activity, rapid, pounding heart beat, increased thirst, and matting or shedding of fur. Over time, this disease relentlessly takes its toll on body organs, including the heart, liver, and other tissues of the body.

If your cat is manifesting one or more of these signs, your veterinarian can collect a blood sample and perform specific thyroid function tests to determine whether your cat has hyperthyroidism.
     
    What are my therapy options?
    Because spontaneous remission of hyperthyroidism does not ever occur, the aim of treatment is to normalize the excessive secretion of thyroid hormone by the cat's thyroid gland. In addition, because almost all of these cats have benign thyroid adenoma(s) and a few have thyroid cancer, a secondary aim of treatment is to remove or destroy the cat's thyroid tumor(s).
     
   

There are three options for the treatment of hyperthyroidism in cats:

1. Medical treatment

2. Surgery

3. Radioiodine (I-131)

   

There are advantages and disadvantages of each form of treatment and these should be considered when selecting the most appropriate treatment.