Animal Emergency and Referral Center of Minnesota’s treatment facility for cats who suffer from hyperthyroid disease is the premiere facility for cat comfort and owner access in the Midwest.

Our caring healthcare team will welcome your cat into a luxurious, window-side cat condo, complete with separate sleeping, eating, and bathroom areas.

As we mentioned previously, there is nothing like our facility in the Midwest! Romeo’s mom drove all the way from Norwich, North Dakota so that he could receive I-131 treatment for his hyperthyroid disease. The following testimonial is from Romeo’s mom!

“We brought our kitty Romeo in for I-131 treatment after our veterinarian suggested it.  From the very first contact, I found the people at AERC to be friendly and everything was explained to me in detail. The drive to bring Romeo in was 8 hours one way, but in the end everything was worth it! We received daily emails with updates on how Romeo was doing and it was obvious that everyone there was dedicated to keeping him as happy and comfortable as possible. His treatment was very successful, and Romeo’s veterinarian will be recommending the treatment and AERC. Overall, I am delighted and my cat is no longer hyperthyroid. Thank you so much for everything, you guys are the best!”    —Shirley


Hyperthyroidism is very common in middle-aged and older cats. 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. 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.


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. For hyperthyroid cats that have normal kidney function, thyroidectomy or I-131 treatment are often recommended. Both of these options provide a cure, and avoid the need for life-long 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.


A single dose of radioactive iodine (I-131) 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 remaining tissue starts producing hormone at more normal levels.

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

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

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

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