One of the reasons the cat was held for four days was to allow for much of the radioactive 131I to be excreted in urine so that the amount of external radiation exposure is significantly reduced. The current Nuclear Regulatory Commission radiation dose limits for individual members of the public are listed below. Despite the extensive blood and urine tests, chest x-rays and physical exams that we require before . Most cats respond to treatment within weeks, although some take up to 6 months to gain the full benefit. Did she have stage 1 prior to treatment for hyperthyroidism or did the stage 1 unmask after treatment started and then jump to stage 4? Since hyperthyroid cats are usually over eight years of age, there is a degree of risk involved. Clients frequently have the following 2 questions when considering radioiodine therapy for their cat's hyperthyroidism. There are three common forms of treatment for hyperthyroidism in cats: medication, radioactive iodine therapy and surgery. The thyroid takes up the radioactive iodine, which destroys cells in the thyroid. Radioactive Iodine Therapy - Advanced Techniques - Specialist Referrals 7 Things You Need to Know About Hyperthyroidism in Cats In cats > 95% of the radioiodine is excreted in the urine. They will then need to take a thyroid supplement. If surgery is the chosen treatment method, the anti-thyroid medication methimazole (Tapazole, Felimazole) may be prescribed for several weeks before the operation. How to choose the right food for your cat. Another significant risk for hyperthyroid cats is not actually related to their thyroid disease. The Disadvantages of Radioiodine Therapy Treatment for Cats, American Veterinary Medical Imaging: Feline Hyperthyroidism, Washington State University College of Veterinary Medicine: Radioactive Iodine Treatment of Hyperthyroid Cats, Washington State University College of Veterinary Medicine: Hyperthyroidism in the Cat, Cornell University College of Veterinary Medicine: Hyperthyroidism in Cats. Laura Porter / Verywell As stated above, it may also be used for a few weeks to stabilize a cat at increased surgical risk because of cardiac complications. Older cats are at greater risk for developing hyperthyroidism. Hair loss. Depending on the dose, radioactive iodine can kill a portion, or all, of your thyroid. The clinical significance of weight gain from the time of diagnosis of hyperthyroidism to 2 years after radioactive iodine therapy is unclear. Hypothyroidism, is a condition resulting from a deficiency of thyroid hormone. Other therapeutic monitoring. 122(6): p. 2444-61. Nuclear Medicine Patient Issues Questions Concerning Domestic Animals. More specific information on what to expect when your cat is treated with radioactive-iodine therapy at Cornell can be found here. The treatment options for hyperthyroidism are: Oral medication. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. Elevated thyroid hormones stimulate an increased heart rate and a stronger contraction of the heart muscle, and can cause thickening of the left ventricle of the heart over time. These positive ions, or free radicals, can cause damage to DNA. You can't visit Fluffy during his stay at the veterinary facility. Some hyperthyroid cats have thyroid cells in abnormal locations calledectopicthyroid tissue (thyroid tissue under the tongue, further down the neck, or all the way to the base of the heart), and they may remain hyperthyroid after surgery. The treatment a cat receives for hyperthyroidism will depend on specific circumstances, including the patients overall health status, the owners ability and willingness to medicate the cat regularly, and financial considerations. You'll need to consider whether to have radioactive iodine (RAI) vs. other treatments for hyperthyroidism and Graves' disease (an immune system disorder that can cause hyperthyroidism). What happens after radioactive iodine treatment for cats? This surgery requires general anesthesia, however, and there might be added risks if older cats have heart, kidney, or other problems that could cause complications. Always check with your veterinarian before changing your pets diet, medication, or physical activity routines. With your cat's diseased thyroid, after methimazole treatment failed, large doses of iodine might have proven effective. . Purraise. In order to produce thyroid hormone (thyroxine), the body needs a supply of iodine. Some people also feel flushed. I-131 therapy does not require anesthesia and eliminates the need for daily medication. Radioactive iodine therapy is a very effective way to treat hyperthyroidism (I-131). The risks associated with low level ingestion of radioactive iodine relate to an increased risk of developing thyroid cancer. Answer posted on 30 March 2019. Radioiodine treatment avoids surgery, anesthesia, and anti-thyroid drugs. These include surgical removal of the thyroid gland (thyroidectomy) or treatment with radioactive iodine. Once his radiation levels come down and you can bring him home, you still have to keep him away from young children and pregnant women, as he'll pass small amounts of radioactive iodine through his urine for approximately two weeks. Cats treated with radioactive iodine for their hyperthyroidism have several risks unrelated to the radioiodine therapy itself. The dose of radioactive iodine is taken orally. Hyperthyroid cats suffer overactive thyroid glands, circulating too much thyroid hormone through their system and affecting nearly every organ. 2000-2023 TheCatSite.com. Slater M.R., Komkov A., Robinson L.E., et al., Long-Term Follow-up of Hyperthyroid Cats Treated with Iodine-131. Because each cat is different, your veterinarian will advise you on the best treatment for your cat. (For example, for human patients we provide instructions such as "sleep in separate beds" and "stay at least 1 meter away from others as much as possible.") These medications do not provide a cure for the disease, but they do allow either short-term or long-term control of hyperthyroidism. (8,9) Replacement hormone products currently on the market, both synthetic and glandular, are not comparable to our own hormone, and in some people, never feel "right". Medication and radioactive iodine therapy are just as effective at treating hyperthyroidism in cats as surgery and are less invasive, so surgical treatment is rarely chosen for treating this condition. The risks of ingesting radioactive iodine and the risks of being around a patient that has been treated with radioactive iodine are very different. Usually, the TT4 level is so high that there is no question about the diagnosis (see the handout "Thyroid Hormone Testing in Cats"). There are no studies that directly link cancer to the low dose radiation used in current medical imaging. Nera just had her 3 month checkup and her T4 level is down to 2.3! Radioactive iodine for cats - is it worth it? - Vet Help Direct 35(3): p. 204-209. Risks unrelated to radioiodine therapy: Unfortunately, 131I has a rather high-energy gamma emission that is difficult to shield. Out little Nera was diagnosed with hyperthyroidism about 4-5 months ago. However, an overactive thyroid is quite common. Iodine-131, Hyperthyroidism, and Radioactive Iodine Therapy Iodine-131 (I-131) is a radioisotope of iodine with a physical half-life of 8.02 days; its primary decay emissions include a 606 keV - particle with 89.6% abundance and a 364 keV -ray with 81.5% abundance (Knolls Atomic Power Lab 2010). The advantages of radioactive iodine therapy are that the procedure most often cures hyperthyroidism, has no serious side effects, and does not require anesthesia. Only about 5% of hyperthyroid cats are younger than 10. Prior to the onset of symptoms he was eating a high quality dry cat food but when he started losing weight and begging for food we were told we could give him some baby food and wet cat food. Committee on Environmental Health. Ten patients (6.4%) had DS (Down Syndrome) and 33 (21.0%) had received ATDs before RAI ablation. Subpart D-Radiation Dose Limits for Individual Members of the Public Also called thyrotoxicosis, hyperthyroidism is caused by an increase in production of thyroid hormones (known as T3 and T4) from an enlarged thyroid gland in a cats neck. There are several treatment options, and your veterinarian will determine the best choice for your cat. Will my cat gain weight after radioactive iodine treatment? The medication can be given life-long or to stabilize the cat before other treatment. Hyperthyroidism is a common condition in older cats. This can be accomplished in several ways: Radioactive iodine therapy. Effect of long-term continuous methimazole treatment of - PubMed Also, you might get some good ideas about what to feed him on Dr. Lisa Pierson's web site. Of course, some people receive no radiation and others much, much more. Since hyperthyroidism can predispose a cat to other conditions, it is important to evaluate general health, with particular focus on the heart and kidneys. Because of the short distances they travel they never exit the patient and as a result no one other than the patient is at risk from exposure to the beta particles unless they internalized the radioiodine excreted by the patient. Malcolm Weir, DVM, MSc, MPH; Krista Williams, BSc, DVM; Robin Downing, DVM, CVPP, CCRP, DAAPM; Ernest Ward, DVM. Due to the damaging effects of hyperthyroid-induced hypertension on your cats kidneys, blood kidney values must be reassessed once the thyroxine level has normalized, even if they were normal on initial blood tests. For the first two weeks after I-131: Keep your cat indoors or supervised when outside to prevent contact with other people. If the disease involves both lobes of the thyroid gland, two surgeries may be required, depending on the surgeon's choice of procedures. All bodily fluids in the cat will have trace amounts of radioactive material within them, but it will be most prevalent within the urine. This may be particularly useful in cats with medical conditions that make other treatment options impossible. Usually this means that the cat will need to be hospitalized for between three and five days after treatment. MyThyroid.com: Radioactive Iodine [Body weight gain after radioiodine therapy in hyperthyroidism] Radioactive Iodine Therapy for Hyperthyroidism - EndocrineWeb The word "individuals" in this context means "people". This treatment is appropriate for cats with more surgical risk due to other health problems or who are exceptionally old. Standards for Protection against Radiation. Objective: To investigate the long-term effects of continuous methimazole (MMI) therapy. Exposure limitations: Because the thyroid needs iodine to produce hormones, the thyroid takes the radioiodine into the thyroid cells and the radiation destroys the overactive thyroid cells over time. How does the risk from medical radiation compare to background radiation exposure? Lifelong administration of methimazole can control the effects of an overactive thyroid gland. It requires two round-trips for you. While I do not know the amount of radioactive 131I that was administered to your cat, the recommendations that your veterinarian has given you are very standard for the industry. The food isnotmedicated. Currently, there's only one FDA approved medication to treat feline hyperthyroidism called methimazole. The brand name of methimazole is called Felimazole. The dosage may vary but typically a cat is given this oral medication twice a day, every 12 hours. . However, because your cat will be radioactive for several days after receiving the shot, precautions must be taken during and after the treatment. Subscribe to always know when we add new material! Toxicology and Applied Pharmacology, 2004. If your cat is showing signs of illness or depression, please contact PVESC. Methimazole blocks excess thyroid hormone production rather than destroying the abnormal thyroid tissue, so the medication must be given for the rest of the cat's life. 2007 07/19/2011; Available from: http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/. What is not taken up by the thyroid will be present in the cat's bodily fluids and will primarily be voided in the cat's urine (in those first four days at the vet hospital). As for your dose, my primary concernespecially if you were allowing the cat to have direct, prolonged contact within the first week of releasewould be the potentially contaminated materials that could result in your intake of radioactive 131I. Surgical removal of the gland under general anesthetic was another option. Anti-thyroid drugs act by reducing the production and release of thyroid hormone from the thyroid gland. How does airline travel expose me to radiation? 5 Best Cat Foods for Hyperthyroidism in 2023 - Hepper When this occurs, a second test, usually afree T4 by equilibrium dialysis (FT4 by ED)or aT3 suppression test,is performed. However, these options tend to be expensive and not possible for all pet owners.