Dr. Tom Smith, of our internal medicine specialists, was trained in the radioiodine treatment of hyperthyroid cats at Kansas State University. He is thoroughly knowledgeable in all aspects of the process, has treated thousands of cats, and offers this treatment at ASEH.

Hyperthyroidism is a fairly common disease of older cats. The thyroid becomes overactive and produces excessive amounts of thyroid hormone. Symptoms include increased appetite and thirst, weight loss, vomiting and diarrhea. Restlessness, vocalization and other behavioral changes are also noted. Heart failure may occur in chronic cases.

There are three treatment options available: Thyroidectomy (surgery to remove the thyroid glands), medication, and radioiodine (I-131).

• Surgery requires anesthesia, is invasive and may not be curative.

• Methimazole or Carbimazole are medications given to control hyperthyroidism and are administered orally or transdermally once to twice daily. Possible side effects are GI upset, blood disorders and liver failure. Frequent bloodwork is required to monitor effectiveness. Both surgery and medication are viable options for treatment of the disease, but not ideal.

• If your cat is in good health overall the radioiodine treatment is the best treatment option. Treatment with radioiodine involves a single injection of the isotope I-131 intravenously, which destroys the diseased thyroid tissue. There are no significant side effects, and radioiodine is 95% effective in curing the disease.

If your regular veterinarian has diagnosed your cat with hyperthyroidism ask them for a referral to our facility for a consultation.

A consultation will be scheduled so that Dr. Smith can examine your pet to determine if he or she is a good candidate for I-131 treatment. Pretreatment diagnostics are required to ensure that I-131 is the best treatment option, and to rule out other diseases. Recent laboratory tests (within the past 2-4 weeks) consisting of a CBC, chemistry, T4, urinalysis and chest radiographs are required, and are typically performed by your regular veterinarian and brought along, with your cat, to the consultation. If Dr. Smith determines that your cat is a candidate we will schedule admission and treatment the following Tuesday.

After treatment you cat will be cared for in our I-131 isolation room until its radiation level is low enough to be safely sent home. The earliest release day would be Thursday of that treatment week. All cats go home by Friday. You will need to take precautions for 2 weeks after discharge as your pet will be emitting low level radiation. A copy of the discharge instructions follows.

Follow-up consists of bloodwork done by your referring veterinarian 4 weeks after treatment to determine the effectiveness of the treatment. We will be more than happy to answer any questions, or concerns, you may have regarding the I-131 treatment so please do not hesitate to give us a call.

Radiation Safety Release Instructions ~ Click here