Treatment for Cats with Hyperthyroid Disease

Animal Emergency and Referral Center's new treatment facility for cats who suffer from hyperthyroid disease is unlike any other in Minnesota.

Our caring healthcare team will welcome your cat into a luxurious, windowside cat condo, complete with separate sleeping, eating and bathroom areas. Your cat will even enjoy watching our resident finches--housed within the center for the amusement of our patients!

Being away from your cat for a week can be difficult, and we understand. That's why we've designed our treatment facility with as much "owner access" as possible. You will be able to view your pet through our observation window during patient "visiting hours." If you wish, you can also view your beloved companion on webcam. No longer will you have to feel isolated from your cat so that he or she can undergo this wonderful treatment.

What is hyperthyroidism?

Hyperthyroidism (also called thyrotoxicosis) is one of the most common diseases of the middle-aged and older cat. It is a multi-system disorder caused by an increase in the amount of thyroid hormones (called T3 and T4) produced by an enlarged thyroid gland. It was first documented in cats almost 30 years ago, but the cause of the disease has been elusive. Although the enlargement in the thyroid gland is caused by a tumor, called an adenoma, it is non-cancerous.

The most common clinical signs of hyperthyroidism in cats include weight loss, increased appetite (although some patients have decreased appetite), vomiting, increased thirst and urination, hyperactivity, and diarrhea. The high levels of thyroid hormones can cause the development of heart disease, and these patients may have a heart murmur, difficulty breathing, high heart rate and arrhythmias.

What are the treatment options for hyperthyroidism?

Once hyperthyroidism has been confirmed, there are several treatment options. They include treatment with radioactive iodine (I-131), surgical removal of the gland (thyroidectomy), and treatment with anti-thyroid medications. The inital choice of treatment is often guided by concern about the patient's kidney function status. For hyperthyroid cats that are assessed with normal kidney function, thyroidectomy or I-131 treatment are often recommended. Both of these options provide a cure of the hyperthyroidism and avoid the need for life-long administration of medications. Where I-131 treatment facilities are available, it is usually the treatment of choice since this option avoids the risks of anesthesia and surgery.

What is I-131 treatment?

A single dose of radioactive iodine eliminates hyperthyroid disease by destroying the tumor within the thyroid gland. I-131 is only absorbed by tissue producing thyroid hormone; the radiation is then given off by the isotope, resulting in destruction of the tumor.

The normal thyroid, typically inactive in hyperthyroid cats, is left intact. Once the hyperactive tissue is destroyed, the tissue is again stimulated to start producing hormone at more normal levels.

It can take several months before the normal thyroid tissue rebounds and thyroid hormone returns to physiologic levels; however, most cats will show clinical improvement almost immediately with a decrease in thirst and appetite, as well as a return to regular activity levels.

Up to 95% of cats will have normal thyroid levels within three months following treatment.

Patients will be surveyed for radioactivity daily, and released post-treatment once radioactive emissions have reached safe levels.

For more information on I-131 treatment, please contact us at (651) 501-3766.