Radioactive iodine (I-131) treatment for feline hyperthyroidism
Understanding Hyperthyroidism
Hyperthyroidism is a common condition in cats, characterized by an overactive thyroid gland producing excessive thyroid hormones. This can lead to various health problems. I-131 treatment is a well-established method to manage this condition.
How I-131 Treatment Works
Radioactive iodine (I-131) emits radiation. When administered, it is absorbed by the hyperactive thyroid cells. The emitted radiation then targets and destroys the abnormal thyroid cells, causing them to become nonfunctional.
Benefits of I-131 Treatment
- High Success Rate: I-131 treatment is highly successful, often leading to a permanent cure for hyperthyroidism.
- Minimal Side Effects: Side effects, if experienced at all, are usually minor and temporary.
- Single Treatment: In most cases, one treatment session is sufficient.
Safety
I-131 treatment is targeted to the abnormal thyroid, affecting only the overactive thyroid cells and sparing healthy tissue.
After Treatment
Your cat will emit low levels of radiation for a brief period after treatment. During this time, your cat will remain hospitalized in an isolation area until the radiation level falls below limits established by state and university safety guidelines. Adhering to safety guidelines provided ensures both your safety and your cat's comfort.
Follow-Up Care
Regular follow-up appointments are necessary to monitor progress. Thyroid hormone levels will be checked to ensure the effectiveness of the treatment.
If you and your veterinarian decide I-131 treatment is the best option for your cat
Your veterinarian will help you set up a referral appointment with the Kansas State University Veterinary Health Center for a complete evaluation and a more detailed discussion of I-131 treatment.
FAQ: Frequently Asked Questions
Radioiodine (I131) treatment at the KSU-Veterinary Health Center
How do I make an appointment?
You can schedule an appointment for your cat by calling the Kansas State University Veterinary Health Center Appointment Desk. Appointments are available on Monday of most weeks.
What happens during my appointment and what information do I need from my veterinarian?
Cats referred for radioiodine treatment have already received a diagnosis of hyperthyroidism and may be receiving medication. Ask your veterinarian for a copy of your cat’s medical record, complete with information about any previous test results and treatments. Once you have scheduled an appointment, your veterinarian is able to send referral information to the KSU-VHC ahead of the appointment or call to discuss the case with one of the Internal Medicine doctors. During your visit, you cat will be examined and have laboratory tests performed to ensure that radioiodine treatment will benefit your cat and can be performed safely. We will discuss our findings and recommendations with you. In planning your visit to KSU-VHC, you should bring your cat’s individual supplies (special food, medications, and special items) to the appointment since cats are admitted directly into the hospital for treatment later in the week.
Do I need to stop methimazole prior to my appointment?
Some cats receive treatment with methimazole (an anti-thyroid drug) to control hyperthyroidism before receiving radioiodine treatment. It is recommended to discontinue methimazole about 7 days before the appointment. This recommendation may not apply in select circumstances, so if there are concerns about discontinuing methimazole treatment, your veterinarian should contact the Internal Medicine Service to discuss options prior to your appointment.
What if my cat isn’t feeling well before my appointment?
Radioiodine treatment is only given when a hyperthyroid cat is medically stable and is feeling well (good appetite, active, and alert). If your hyperthyroid cat acts sick or becomes ill, you should schedule a visit with your veterinarian to investigate the problem. If a hyperthyroid cat is sick or ill at the time of your KSU-VHC appointment, radioiodine treatment will be delayed until the problem is resolved and your cat is feeling better.
What if my cat has other medical problems, can radioiodine treatment still be done?
There is no single answer to this question. Most cats are able to undergo successful treatment with radioiodine but, unfortunately, some hyperthyroid cats are not good candidates to receive radioiodine if they also have other medical condition (chronic kidney disease, for example). Your veterinarian should consult with the Internal Medicine Service if there is concern whether your cat is a good candidate for treatment. Before your cat is treated at the KSU-VHC, a thorough evaluation is done to provide you with the best recommendations for your cat’s treatment.