So what does it mean if your senior couch potato of a cat suddenly loses a bunch of weight, is ravenously hungry and thirsty, and spends hours swinging from the curtains rather than gluing themselves to the nearest lap? It’s likely that your cat has hyperthyroidism.
Hyperthyroidism is the most common endocrine disease in cats, especially among those 13 years of age or older, and is caused by the overproduction of key metabolic hormones in the thyroid glands (located in the neck). While hyperthyroidism can have a negative impact on various bodily systems if it is left untreated, there are effective treatments available to alleviate symptoms and restore your cat’s health.
At Community Cat Clinic, your cat’s health is our number-one priority and we are proud to offer radioiodine therapy (also called I-131 therapy), the treatment of choice for cats suffering with hyperthyroidism. Radioiodine therapy is delivered with only one injection and boasts a 95% or higher success rate. No surgery or lifelong medication is necessary to restore your cat to good health.
Want to know more? Here are answers to the most frequently asked questions we receive about hyperthyroidism and radioiodine therapy:
What is hyperthyroidism?
Hyperthyroidism occurs when the thyroid gland produces more hormones than your cat’s body needs. These hormones regulate the body’s metabolism, growth, and development. The most frequent cause is a non-cancerous tumor on the gland, with very rare cases linked to malignant tumors. The disease revs up your cat’s metabolism and can be devastating to the heart, kidneys, and other bodily systems. Early treatment is key to avoiding secondary issues and ensuring a positive outcome.
How do I know if my cat has hyperthyroidism?
In addition to the symptoms mentioned above, hyperthyroidism may lead to
- Vomiting
- Diarrhea
- Rapid or difficulty breathing
- Abnormal heartbeat
- Aggression
- Excessive talking
- An enlarged thyroid gland, which feels like a lump on the neck
Fewer than 10% of cats with hyperthyroidism exhibit loss of appetite, depression, and weakness.
What tests need to be done to confirm if my cat has hyperthyroidism?
At Community Cat Clinic, we confirm the diagnosis with a blood chemistry profile that measures your cat’s T4 (thyroid hormone level). We also take a complete blood count (CBC), check your cat’s basic organ chemistry and urine, and screen for cancer and heart disease with a chest x-ray.
How does radioiodine treatment work?
Iodine plays a crucial role in hormone production by the thyroid gland. Radioiodine I-131, a radioactive form of iodine, selectively accumulates in abnormal thyroid tissue while sparing other body tissues. This targeted action allows it to effectively destroy overactive thyroid tissue without causing excessive radiation exposure to the rest of the body.
When your cat undergoes treatment for hyperthyroidism at Community Cat Clinic, they receive a single injection of radioiodine and are then monitored closely for any side effects. Some cats experience a temporary worsening of clinical signs (such as increased vocalization or lethargy) shortly after the administration of radioiodine. This is usually short-lived and resolves on its own. After treatment, the irradiated thyroid cells gradually die off and the blood levels of thyroid hormone normalize in most cats.
Will the treatment make my cat sick?
Radioiodine treatment for hyperthyroidism in cats is generally well-tolerated, and severe side effects are rare. Unlike traditional radiation therapy or chemotherapy for humans, radioiodine treatment in cats is highly targeted and focused on the thyroid tissue. That means your cat will not experience debilitating symptoms such as intense fatigue, hair loss, or vomiting
While uncommon, cats occasionally develop hypothyroidism (underactive thyroid gland) after treatment. This is easily controlled with thyroid supplementation and may not be permanent.
Why does Community Cat Clinic prefer radioiodine treatment?
Community Cat Clinic prefers radioiodine treatment for hyperthyroidism over other options due to several compelling reasons. Unlike medical therapy, where daily administration of oral drugs like Tapazole (methimazole) is required for the rest of the cat’s life, radioiodine treatment offers a one-time intervention with the potential for a cure. Not to mention, pilling a cat daily can be challenging and stressful for both the pet and the owner.
Medical therapy can lead to serious blood or liver problems, necessitating regular blood tests to monitor the cat’s overall health. Radioiodine treatment is a safer, more straightforward treatment approach because it avoids these complications.
While surgery is generally an effective treatment for hyperthyroidism, the required sedation poses some risks. Since cats with hyperthyroidism often have heart issues as well, the risks of sedating them are even higher. The surgery itself likewise poses potential risks such as damage to the adjacent parathyroid glands, which can lead to a life-threatening risk of low blood calcium. Lastly, there is a small risk that surgery may not completely cure hyperthyroidism or that the condition might recur over time.
The biggest drawback of radioiodine treatment is that your cat will have to stay with us at Community Cat Clinic for several days following their treatment so we can monitor their response. Patients are hospitalized in our nuclear medicine ward for four nights, during which time they will be cared for by our dedicated vet staff. You will receive regular progress reports by telephone or email, ensuring transparency and communication throughout the treatment process.
Why does my cat need to stay in the hospital after the treatment?
Your cat must stay with us in our nuclear medicine ward until levels of radioiodine in their bodies fall below state guidelines. For this reason, you will not be able to visit your cat during this time period though you will receive daily updates. In addition, once therapy has commenced clients are unable to discontinue treatment or request an early release. These guidelines are in accordance with federal regulations governing radiation safety.
You will receive thorough instructions before your cat’s admission to the Community Cat Clinic, including written guidelines for handling your pet during the two-week period following release from therapy.
What happens when my cat is released from your clinic?
Upon discharge, your cat will still be minimally radioactive. Even though the level of radioactivity is very low, you should still take precautions during this period, including isolating your cat in a spare room for two weeks. During this period you will have to limit close contact such as snuggling and sleeping together. Your cat also cannot sleep in your bedroom.
Because your cat eliminates any residual radioactivity through their urine and feces, you may use flushable litter for one week. Wear disposable gloves while cleaning the litter pan and wash your hands thoroughly afterwards. If you prefer to use litter that cannot be disposed of in the toilet, you must store the dirty litter for two weeks, when it is safe to discard.
There are a few additional restrictions about handling your cat if you are pregnant or nursing, or if there are small children in the household, and we are happy to discuss these with you prior to deciding on treatment.
What aftercare will my cat need?
The vast majority of cats require no specific aftercare. However, Community Cat Clinic requires a recheck of your kitty’s T4 and kidney values 90 days after radioiodine therapy is completed.
Does radioiodine treatment always cure hyperthyroidism?
Radioiodine treatment is highly effective, curing hyperthyroidism in greater than 90% of treated cats. Even those not completely cured after one treatment show improvement in thyroid hormone concentrations and clinical symptoms. If hyperthyroidism persists beyond six months post-treatment, re-treatment is recommended and virtually ensures a cure. Following the first treatment, 96% of cats do not require medication, except for those with large tumors, who may need L-thyroxine supplementation. Additional treatment may be necessary if underlying diseases are present.
Can hyperthyroidism ever come back?
Although it is uncommon, hyperthyroidism can recur after radioiodine treatment. Reoccurrences usually develop three years or longer after the first treatment. Relapses may indicate the development of a new thyroid tumor, rather than a relapse from the first tumor treated with radioiodine.
What should I do on the day of treatment?
On the day of treatment, bring your cat to Community Cat Clinic at the scheduled time, ensuring they have been fed (fasting is not necessary). If your cat has specific dietary preferences, bring the preferred food for their hospitalization. Avoid bringing personal items like blankets or toys due to contamination concerns. Leave a carrier with us for the ride home, as your cat must be transported in it.
Additionally, bring any X-rays taken of your cat (we will want to see these ahead of time at our pre-treatment consultation visit). Our vet team will provide a comprehensive explanation of hyperthyroidism and I-131 treatment, addressing any remaining questions you may have during the appointment.
How much will the treatment cost?
The cost for radioiodine therapy varies depending on a number of factors, the cost of the radioiodine itself plus fees for the pre-treatment exam and labs, hospitalization fees and treatment of any additional underlying health issues.
Payment is required when you bring in your cat for treatment). Method of payment may include cash, check or charge cards (Visa, Master Card, Discover, or American Express); we also can provide you with information if you need help covering the cost.
Contact us for more information about how Community Cat Clinic can help your hyperthyroid cat get back to his old self again.
