Why I Chose Radioactive Iodine Treatment for Both of My Cats with Hyperthyroidism


I had not one but two cats who developed hyperthyroidism. Both were at least 15, and both were female. With both cats, I ended up choosing radioactive iodine treatment to treat it, and I was happy with the results.

If you are considering such a decision, perhaps the stories of Karma and Kali will help give you insight into whatever path you choose. I used the services of Dr. Ralph Wiechselbaum, DVM, Ph.D., who specializes in radioactive iodine treatment and ultrasound (and is quite a cat guy as well). Dr. Ralph offers some insight into hyperthyroidism treatment in this article.

1. Karma’s story

We knew something was wrong when the already-small Karma began losing weight, no matter how much I fed her. She also became more vocal. These are some of the possible signs of hyperthyroidism, but my vet has told me that this disease manifests differently in every cat. The definitive answer to whether the disease is present requires a blood test. Karma was very hyperthyroid, it turned out. I knew that the options were surgery (which one vet told me was very tricky and not always effective), medication in the form of a pill, and radioactive iodine treatment.

Not wanting to jump right into the expense of the iodine treatment (which ranges from $900 to $1400), we tried the pill medication. But Karma had a bad reaction to the pill and developed a severe skin reaction around her head. She seemed quite uncomfortable and the medication did not seem to be improving the symptoms. (It has been my experience that getting the dosage of the pill correct for a cat involves some trial and error; it can be tricky.)

We committed to the radioactive iodine treatment, and I drove with Karma for two hours to her initial meeting with Dr. Ralph. She was given an echocardiogram (feline hyperthyroidism can make the heart race and can lead to heart damage). Dr. Ralph then drove with her an additional two hours to his treatment facility in Minneapolis.

Fortunately, Karma is a good rider. She underwent two weeks of quarantined treatment, and received radioactive iodine in the form of a daily pill. Sadly, this happened over Thanksgiving. It was very strange to be minus one of the family over a holiday, but Dr. Ralph was extremely good about daily updates. Karma sailed through the procedure and came home two weeks later.

Dr. Ralph did another echocardiogram after the treatment. Radioactive iodine treatment worked well for Karma — her heart slowed, her thyroid levels came down to normal, and she began to put on weight again. Karma lived for a few years after her treatment. Dr. Ralph kindly let me stretch out payments for the until I was able to pay off the balance.

2. Kali’s story

My sweet and passionate Kali started showing symptoms of hyperthyroidism about a year after Karma’s treatment. It was a little different — Kali didn’t show an increase in vocalization. But she did lose weight, and like Karma, she was already a very small cat. By the time we realized what was going on (she had other health issues, as well), her weight was very low, and we decided to simply do the radioactive iodine treatment again because it had worked well for Karma. Kali got through quarantine and recovery very well. In truth, it’s probably harder for the humans than the cats.

Is this treatment for everyone?

Cost was a huge factor for us, and the treatment wouldn’t have been possible if Dr. Ralph hadn’t been willing to let us pay in increments. Cost is a barrier for many. But Dr. Ralph says that the radioactive iodine treatment may be the most economical of all the options, in the long run. With other treatments there are additional costs of routine and repeated lab work, and possible costs for special food.

“I try not to make cost a factor for my clients. It is roughly $1,300 for the treatment, two echocardiograms, and some follow-up lab work. Most people will spend that on medication and lab work in 14 to 16 months or less and still have a hyperthyroid cat,” he says.

Letting clients make payments at a rate they can handle also makes the cost (over time) more comparable to other treatments. Dr. Ralph, who has treated 3,300 cats over 15 years, says that he’s found that the treatment is actually saving people money if the cats live more than 14 to 16 months after the treatment.

Commenting on other treatment options, Dr. Ralph says, “Methimazole is OK, but watch very carefully for adverse reactions ÔÇô- they are much more frequent than is reported in the veterinary literature.” If the cat lives long enough, there will be a point in which you cannot give enough medication to be effective without it being toxic (and thus you’ll have to go to the Iodine to save them). And with surgery, expect to repeat it in about a year, in most cases.

Dr. Ralph believes that radioactive iodine therapy is the best approach for feline hyperthyroidism, because it is the only true cure. All other treatments are only managing the clinical signs of the underlying tumor, which continues to grow; the medication is highly toxic in many cats; the food actually is quite expensive and accelerates the underlying growth of the tumor; and surgery has a tumor recurrence rate of as high as 80 percent.

Have you had experience with feline hyperthyroidism? Share your insights in the comments!

Read more on feline hyperthyroidism:

More by Catherine Holm:

About Catherine Holm: Told that she is funny but doesn’t know it, accused of being an unintentional con artist by her husband, quiet, with frequent unannounced bursts into dancing liveliness, Cat Holm loves writing about, working for, and living with cats. She is the author of The Great Purr (cat fantasy novel out June 1), the cat-themed memoir Driving with Cats: Ours for a Short Time, the creator of Ann Catanzaro cat fantasy story gift books, and the author of two short story collections. She loves to dance, be outside whenever possible, read, play with cats, make music, do and teach yoga, and write. Cat lives in the woods, which she loves as much as really dark chocolate, and gets regular inspiration shots along with her double espresso shots from the city.

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