Radioactive Iodine Treatment for Cats with Hyperthyroidism

What is Hyperthyroidism?

Radioactive Iodine Treatment for Cats with Hyperthyroidism
Information for Pet Owners

What is Hyperthyroidism?
Hyperthyroidism is a metabolic disease that is caused by excessive secretion of thyroid hormone. It is most often caused by a benign tumor of the thyroid gland. Weight loss, vomiting, increased appetite, and poor hair coat are the most common clinical signs

How can hyperthyroidism be treated?
• Medical Treatment: This consists of the twice daily administration of a drug called methimazole. This will usually control the disease but is not a cure, and must be given for the rest of the cat’s life.
Radioactive Iodine: This is a simple treatment consisting of a single subcutaneous injection of radioactive iodine. It carries a 95% cure rate.

Why Radioactive Iodine
• It is curative
• Some cats are difficult if not impossible to pill and Iodine removes the necessity for daily medicating.
• Methimazole can cause systemic reactions in some cats
• Frequent blood tests are no longer required as Iodine cures the disease
• Anesthesia is not required for the treatment
• No surgical complications related to the parathyroid gland

How is the Iodine administered?
• A single subcutaneous injection similar to vaccination

How long will my pet be hospitalized?
Because Iodine is radioactive, the New York State Department of Health requires a period of isolation.  We have recently received approval to release pets as early as three days after treatment. Your pet will be cared for in our feline only facility. Large comfortable cubicles with a private litterbox area are provided. There is a wonderful view of the tennis courts behind the facility. Your pet will be evaluated twice daily. Because our iodine facility is located at the Cat Hospital, there is always a doctor familiar with nuclear medicine available to evaluate your pet’s condition.

At discharge you will be given an instruction sheet that outlines what precautions you need to take when you bring you pet home. For a period of two weeks the following actions should be taken:

• You should use flushable litter for a period of two weeks
• You should not sleep with your pet for two weeks
• Limit close contact to a few minutes for two weeks.
• You do not need to quarantine your cat from other pets
• Recheck with RVMD at three months for serum chem and T4
• You do not need to quarantine your cat from other pets
• No contact with: Pregnant women, Immune compromised people, and chemotherapy patients.
Success Rates
We expect a 95% cure rate with radioactive iodine. This means that you cat is no longer hyperthyroid and does not need medication of any type
Instructions for referring veterinarians

Listed below you will find the protocol and information necessary to refer a cat to the Feline Hyperthyroid Treatment Center. The following is a guideline that we follow to ensure the best success rates possible.

Diagnostic Testing
• Complete Blood Count, Serum Chemistry Profile, Urinalysis (within 30 days of referral)
• Pretreatment Serum T4 level (within 30 days of referral)
• Chest radiographs, echocardiogram, ECG. (at your discretion, and particularly if severe cardiac disease is suspected)
• If the patient has been treated with tapazole for some time, please discontinue the medication for one week and collect a serum T4.
The above information, along with the client contact information should be faxed to our office at (516)-746-4813. It will be reviewed by our nuclear medicine staff. At this point one of our doctors will be happy to contact you, or if you prefer the client directly, to discuss the patient’s suitability for treatment.

Follow-up care
At the end of the one week stay in our facility blood will be collected to evaluate thyroid, liver, and kidney function. We will forward a case report and the lab work to your office. The client will be instructed to return to your office in 3 months for follow-up. At that time a serum T4, as well as any other metabolic profiles you feel are appropriate should be submitted to the laboratory. Studies indicate that over 95% of treated cats will have thyroid values that are within the normal range.

If you have any questions about any of this information, or you wish to discuss a particular patient, please do not hesitate to call our office.

Feline Hyperthyroid Treatment Center
2 Hillside Avenue
Suite E
Williston Park, NY 11596