Client Information Sheet on Radioactive Iodine Therapy for Hyperthyroid Cats

What is hyperthyroidism?
Hyperthyroidism is a very common endocrine disease of older cats usually caused by a benign tumor of the thyroid gland. It causes an increased metabolic rate which in turn causes a variety of signs including weight loss, vomiting, diarrhea, rapid or irregular heart rate, increased blood pressure or other problems.

What are the treatment options for hyperthyroidism?
The three primary options for treatment of hyperthyroidism include surgical removal of the affected thyroid gland, medical therapy with Tapazole (methimazole), or radioiodine therapy.  Complications associated with surgery include anesthetic risks and damage to the parathyroid gland primarily, as well as risk of recurrence.  Tapazole therapy can cause vomiting, skin rash, as well as liver and bone marrow problems.  In addition to daily pilling, close monitoring of blood work is essential with Tapazole therapy, and can incur costs in excess of $500 or more per year.

What is radioiodine therapy (aka Radioactive iodine, I131)?
Radioiodine (I131) therapy has been used extensively in veterinary medicine and has a success rate approaching 95-98% for hyperthyroid cats with only one treatment.  The radioactive iodine is absorbed into the abnormal thyroid tissue (regardless of location), leaving nearby normal thyroid tissue and other organs undamaged.  Your cat's normal thyroid tissue will resume functioning after the benign tumor is gone, usually within a month of therapy.  In rare cases (<5%), some cats may require a second treatment or develop hypothyroidism (under-active thyroid gland) that requires daily thyroid hormone supplementation.

Why does my cat have to remain hospitalized for so long after treatment?
Because the radioactive material remains in the cat's body and is excreted primarily through the urine and feces, your cat is required by Tennessee state law to remain in our facility until his/her levels are considered low enough for discharge.  The standard hospital stay is about 5 days, though some cases may require an extended stay.  While hospitalized, your cat will be monitored daily by a trained staff member as well as a veterinarian.  Medications will be administered as needed, and we encourage you to bring a week's supply of your cat's favorite food.  Unfortunately, no personal effects can be returned so we suggest not leaving any cat toys or bedding (we will provide these).  Also, by law, we cannot allow visitation until your cat is ready for discharge, but we will give you daily progress reports on your cat.

What is required following discharge from the hospital?
For two weeks following discharge, we request you follow some sensible safety measures while any remaining radiation is excreted from your cat's body.  You will receive detailed written instructions that include limiting extensive contact (especially with children or pregnant women), washing hands after handling your cat or his/her litter box, and disposing of litter box waste. Your cat will also need to remain indoors during that time.

Will my cat experience radiation sickness?
The treatment is given via a subcutaneous injection, similar to a vaccination.  They do not experience radiation sickness.  Radioactive iodine is a very safe and effective treatment and is used frequently in human medicine.

What does radioiodine cost?
Your cat will require a number of tests before we can determine if he or she is a good candidate for I131 therapy.  Please check with your veterinarian for the cost of these tests.  Once eligible for treatment, you will be asked to make an appointment with our internal medicine department to review these records, examine your cat further as a possible treatment candidate and discuss the treatment.  This initial consultation fee is $104 regardless of whether or not you choose to pursue I131 treatment for your cat.  If your cat is determined to be a good candidate, we will schedule the I131 treatment for the next available Monday.  The treatment fee is $950-1000, which includes the I-131 treatment, monitoring, specialized waste disposal, standard 5-day hospitalization, litter kit and post-treatment telephone consultation with your veterinarian.  This fee does not include any pre-treatment lab work, emergency fees incurred while hospitalized, extended hospitalization, or post-treatment lab work.  Your cat will require follow-up blood tests after I131 therapy to recheck thyroid hormone levels and kidney values (check with your veterinarian for these fees).  Because the I131 must be special ordered for your cat (and cannot be returned or saved due to decay), we will require a non-refundable deposit at the time the appointment for treatment is scheduled.

How do I schedule an appointment for I-131 for my cat?
Please talk with your veterinarian about your cat's case and whether he or she is an appropriate candidate for I-131.  MedVet is a referral only hospital which means we work closely with your veterinarian to provide the best care possible for your cat.  We require a referral from your veterinarian before we can see your cat for evaluation or treatment.

Thank you.

MedVet Memphis, LLC