Why isn't there a study directly linking medical imaging and cancer? Because the radioactive iodine used (known as iodine 131) may expose those around you to the effects of radiation (and theoretically negatively affect their thyroid glands), you will be given guidelines on how to prevent such exposure. What they are trying to prevent is the intake (ingestion, etc.) American Academy of Pediatrics. This treatment involves administering an injection of iodine with a radioactive substance attached. You should talk with your veterinarian about what diets may be best for him in this case. 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. No individual breed is known to have a greater risk, although Siamese, Burmese, Persian, Abyssinian, Tonkinese, and British shorthair breeds appear to have a somewhat decreased incidence of hyperthyroidism compared to other breeds. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. To answer these questions we have to separate the risks associated with internalizing (i.e., ingesting) radioactive iodine from the risks of being around a patient that has been treated with radioactive iodine. We found out about the radioactive iodine treatment and after lots.of research decided this was the way to go. Lack of appetite. This information is not a substitute for a vets opinion. Clients owning hyperthyroid cats undergoing radioiodine therapy are always considered members of the general public. Wet food is much better for him anyhow, so this is a good time to get him settled on it. The radioiodine is eliminated in urine and feces. Because of strict treatment guidelines, most facilities will not allow visitors during this quarantine period. 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. of the radioactive iodine into your body because, just like the cat, any 131I intake you have will result in an uptake by your thyroid and in larger quantities could result in significant thyroid dose. 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). Surgical removal of the gland under general anesthetic was another option. Try mixing baby food chicken or turkey in with some Fancy Feast. About 25% of cats with hyperthyroidism become hypertensive. Depending on the dose of radioactive iodine chosen, and the disease under treatment (Grave's vs toxic goitre, vs hot nodule etc), success rate in achieving definitive resolution of the hyperthyroidism . Weight change was analyzed in only 228 patients and 84% gained weight by 1 year after radioactive iodine therapy. Many organs are affected by hyperthyroidism, especially the heart. Most cats with hyperthyroidism have elevated levels of the thyroid hormone T4 in their bloodstream, but a small percentage of cats with hyperthyroidism have T4 levels within the normal range. Actually it is quite safe, because the radioactive iodine is absorbed only by thyroid cells; no other cells in the body are exposed to the radiation. Since hyperthyroid cats are usually over eight years of age, there is a degree of risk involved. Natural background radiation exposure accounts for an average of 3.1 mSv/yr with variations depending on where you live. To date the studies following hyperthyroid cats treated with radioiodine have not shown any increased incidence of cancer (thyroid or other types) associated with radioiodine therapy. Most hyperthyroid cats respond fully to a single injection with radio-iodine. The radioactive iodine is useful in treating the condition that your veterinarian has diagnosed in your cat. The veterinarian's recommendations are to isolate my cat for at least two weeks. Gained over three pounds! Hypertension develops due to the increased pumping pressure and elevated heart rate that occurs with hyperthyroidism. Many doctors recommend that women avoid becoming pregnant for 6 months to a year after treatment. The current Nuclear Regulatory Commission radiation dose limits for individual members of the public are listed below. The radioactive isotope, Iodine-131 ( 131 I), is administered as a one-off injection. Surgery will be performed if your cat successfully undergoes the initial treatment without complication. Some rare cases of hyperthyroid disease are caused by malignant tumors known as thyroid adenocarcinomas. Dr. Linder has received speaker fees or research fudning from Hills Pet Nutrition, Nestl Purina PetCare, Royal Canin, and Virbac, and has provided professional services for Mark Morris Institute. Radioactive iodine therapy is curative within three months of therapy in approximately 95 percent of all hyperthyroid cases. Iodine is an element normally taken up in large amounts by the thyroid gland, even more so in cats that are hyperthyroid. 8. Cats treated with radioactive iodine for their hyperthyroidism have several risks unrelated to the radioiodine therapy itself. Of course some cats treated with radioiodine for their hyperthyroidism will go on to get cancer, but in the same proportion as hyperthyroid cats treated with methimazole or surgery. Mean baseline age was 12.7 3.0 years and mean baseline BMI SDS was 0.003 1.18 kg/m 2. Discuss these issues with your veterinarian when considering dietary iodine restriction as a treatment for hyperthyroidism in cats. About TheCatSite.com. Most cats with uncomplicated hyperthyroidism will live several years following treatment of hyperthyroidism, unless they develop another disease. Nuclear Medicine Patient Issues Questions Concerning Domestic Animals. Site Help | We fed him some Fancy Feast again last night and he ate it all without vomiting. So in this case the targeted radiation exposure is actually increasing survival for these patients. The beta particles, which are much more potent forms of radiation, travel an average distance of less than 1 mm. Supporting Cat Health with Information and Health Studies. If we restrict iodine, production of thyroxine decreases. 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. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society. Clients frequently have the following 2 questions when considering radioiodine therapy for their cat's hyperthyroidism. The treatment options for hyperthyroidism are: Oral medication. The good news is that virtually every client will already take steps to avoid this, even when radioactive iodine in their cat's urine is not the motivation. A large study found an increase in some cancer types in people who had radioactive iodine treatment for hyperthyroidism compared with the general population. Giving him medication once or twice a day isn't an option, although if it's a medication that can be mixed in with his food, it's something you could discuss with the veterinary staff at the facility. ), family history (genetics) or radiation exposure. Radioactive Iodine Therapy Occasionally cats will act like they may have a sore throat for a couple of days after the radioiodine therapy. In more serious cases, surgical removal of the thyroid glands may be required. The anti-thyroid pill is methimazole, also known as Tapazole. Part 20, Standards for protection against radiation Cats havetwo thyroid glands in the neck that are vital in regulating the body's metabolic rate. JavaScript is disabled. Looking for a convenient way to access your pets health records, refill prescriptions, view upcoming appointments and more? Some cats develop side effects from methimazole, such as vomiting, lethargy, anorexia, fever, liver damage, anemia, and a decrease in white blood cells. Methods: Therapy and body weight related data of 100 consecutive RITh-patients were retrospectively analysed from the time before up to three years after RITh. Once the correct dose of radioiodine has been determined and administered, most of the time the tumors responsible for causing the elevated thyroid levels resolve and the cats are cured. This treatment is appropriate for cats with more surgical risk due to other health problems or who are exceptionally old. Radioactive iodine therapy offers a cure through a simple injection that returns thyroid function to normal levels. What Treats Can I Give my Dog with CalciumOxalateStones? The most common clinical signs of hyperthyroidism are weight loss, increased appetite, and increased thirst and urination. In many cats, only one thyroid lobe is abnormal, so only one surgery is needed. A Multicompartmental Model for Iodide, Thyroxine, and Triiodothyronine Metabolism in Normal and Spontaneously Hyperthyroid Cats. Long-Term Health and Predictors of Survival for Hyperthyroid Cats Treated with Iodine 131. 2000-2023 TheCatSite.com. For a better experience, please enable JavaScript in your browser before proceeding. Interestingly, when higher doses are given, like those received by the patient treated for hyperthyroidism or thyroid cancer, then the injury to the cells is terminal and hence the cells do not survive to go on to become malignant. It has to do with how important your thyroid is in regulating your metabolism and your weight. Hypothyroidism, is a condition resulting from a deficiency of thyroid hormone. Regardless of the medication, blood tests should be conducted periodically during treatment to evaluate whether the therapy is effective and to monitor kidney function and for potential side effects. Oftentimes it takes decades for cancer to be detected following radiation exposure. Although the cause of feline hyperthyroidism is not known, possible contributing factors include deficiencies or excesses of certain compounds in the diet and chronic exposure to thyroid-disrupting chemicals in food or the environment. Ultimately of course, these conditions can be diagnosed. The other conditions that cats can develop at this age are numerous and varied. Usually this means that the cat will need to be hospitalized for between three and five days after treatment. The School of Veterinary Medicine's Ryan Hospital, however, is one of the few veterinary centers in the region to offer a treatment that can cure the disease: a single shot of radioactive iodine, I-131. (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". . If the nearest facility is far away, there's the stress or travel for both you and Fluffy, as well as possible hotel and other travel expenses. Your cat can receive methimazole, a medication that inhibits thyroid hormone production. She has spoken at national and international conferences and a Capitol Hillbriefing, and is an expert in pet obesity, nutrition communication, and in the human-animal bond. Several complications of hyperthyroidism can be significant, includinghypertension(high blood pressure) and a heart disease called thyrotoxic cardiomyopathy. Jeff Brunette, CHP, Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. People may take RAI . The most common clinical sign of hyperthyroidism is weight loss due to the increased rate of metabolism despite an increased appetite. For the same reasons as surgical treatment, your cat will likely be started on methimazole for about a month before radioactive iodine therapy. The effectiveness of this transdermal gel is acceptable in most cases. 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. These tests are needed to evaluate your cats overall health and predict the likelihood of complications with the chosen treatment protocol. The coat of affected cats may appear unkempt, matted, or greasy (see Figure 1). J Vet Intern Med, 2001. By Log in 24/7 to access your pets health care information. However, it may not be the best treatment for your particular cat. The first step is determining the blood level of one of the thyroid hormones calledtotal thyroxine (TT4). Hyperthyroidism is a common condition in older cats. Radioactive iodine targets the thyroid tissue - as this is the only tissue in the body that uses significant quantities of iodine. Affiliate of Mars Inc. 2023 | Copyright VCA Animal Hospitals all rights reserved. Because metabolism is altered in hyperthyroidism, it's important to monitor your cat's weight and muscle mass. When this occurs, a second test, usually afree T4 by equilibrium dialysis (FT4 by ED)or aT3 suppression test,is performed. Thank you! As in the case of heart disease, after the hyperthyroidism has been successfully treated, high blood pressure will often resolve, and permanent treatment for it may not be required. Learn more about the Clinical Nutrition Team at Tufts. Even after treatment it may take a long time to reverse weight loss and muscle loss that occurred before your cats diagnosis. While the concept of radiation hormesiswould suggest a potential benefit from exposure to low levels of ionizing radiation by stimulating the immune system's ability to repair DNA, any potential benefit is poorly defined and hence the current recommendations surrounding radiation exposure follow the As Low As Reasonably Achievable (ALARA) concept. It is important to drink fluids after your treatment and for the next 2 days. I have a cat also and I know when she is happy and purring while sitting on my lap getting strokes, she drools. Pediatrics, 1998. TheCatSite.com participates in select affiliate advertising programs, including the Amazon Services LLC Associates Program. Hyperthyroidism & Liver Function in Cats, Intervals of Depo-Medrol Injections for Cats. Nera just had her 3 month checkup and her T4 level is down to 2.3! If these tests are not diagnostic, athyroid scan (thyroid scintigraphy)can be performed at a veterinary referral center, or the TT4 can be measured again in a few weeks. Only certain facilities perform this procedure, which consists of giving your cat a shot of radioactive iodine, which gets rid of abnormal thyroid cells without harming normal ones. Follow up blood work is essential to ensure kitty does not become hypothyroid which is too little thyroid. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Radioactive iodine therapy. 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). Should we just cut him off "cold turkey" (pun intended) and hope he finds fulfillment and eventual weight gain with his old diet of dry food? By 14 days after treatment, the radioactivity will have decayed to a very low level. If the total GFR is below this number, medical therapy for hyperthyroidism may be recommended, although I-131 treatment may still be an option in specific patients. Calabrese E.J., Hormesis: From Marginalization to Mainstream: A Case for Hormesis as the Default Dose-Response Model in Risk Assessment. RAI is a form of radioactive nuclear medication that permanently destroys thyroid tissue. There are two types of radiation exposure that your vet is trying to minimizeexternal exposure from the radioactive material within the cat's body, and the radioactive materials in the cat's urine and other bodily fluids released by the cat that you may come into contact with and may end up being ingested or absorbed by you accidentally. With this therapy, you take radioactive iodine (radioiodine) by mouth. 228(4): p. 559-63. (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.") This can be accomplished in several ways: Radioactive iodine therapy. Of course, some people receive no radiation and others much, much more. Hyperthyroidism is a common condition in older cats because of an excess of circulating thyroid hormone, called thyroxine. The thyroid gland, located in the neck, is responsible for the bodys metabolism. Out little Nera was diagnosed with hyperthyroidism about 4-5 months ago. An anti-thyroid medication, like methimazole. Feeding Hyperthyroid Cats Iodine restriction may help; weight loss is a . Some people also feel flushed. Having said that, the clients who own the cats we treat with radioiodine should make every effort to avoid ingesting any contents from the litter box. This means that our radioactive materials license requires our practice ensure that our clients receive less than 1 mSv of radiation exposure as the result of our treatment of their hyperthyroid cat with radioiodine. . Title 10, Code of Federal Regulations The normal thyroid cells will therefore not take up any radioactive iodine. This is due to increased stimulation in the nervous system which is a common occurrence in cats with feline hyperthyroidism. Too cold? In some of these cats, blood pressure can become so high that retinal bleeding or retinal detachment will occur, resulting in sudden blindness. The information posted on this web page is intended as general reference information only. Generally, about 5 to 10 pounds of excess weight can likely be attributed to the lack of thyroid hormones that occurs in people diagnosed with hypothyroidism. These include weight loss, increased activity, and kitten like behaviour. 2004. This cat is showing weight loss and poor coat - typical signs of hyperthyroidism. The total effective dose equivalent to individual members of the public from the licensed operation does not exceed 1 mSv in a year, exclusive of the dose contributions from background radiation, from any administration the individual has received, from exposure to individuals administered radioactive material. Reduce the time near a source, increase the distance from the source, or use some sort of radiation absorbing shielding between you and the source of radiation and you will reduce your radiation dose. The risks of ingesting radioactive iodine and the risks of being around a patient that has been treated with radioactive iodine are very different. What is taken up by the thyroid will be released slowly over the next days/weeks to the other bodily fluids which is why they have the precautions that you describe. There are fundamental differences between a continuous dose over a year (background radiation) and a dose that occurs over a few seconds like in CT, but these are helpful comparisons. Side effects may include fluid retention, weight gain, elevated . In the US, the average person is exposed to an additional 3.0 mSv/yr from medical sources (predominantly CT scans). Luckily these risks will diminish in time following successful radioiodine therapy and a return to a persistently normal thyroid level. Radioiodine treatment avoids surgery, anesthesia, and anti-thyroid drugs. Environmental risk factors have been investigated and may predispose some cats to hyperthyroidism, although the specific mechanisms are unknown. Surgical patients may become hyperthyroid again if abnormal cells are missed during surgery or if new abnormal cells develop. 35(3): p. 204-209. Fewer than 2% of hyperthyroid cases in cats involve malignant thyroid gland tumors. After treatment, the normal thyroid tissue will regain full function within 1-3 months. You may gain weight after you undergo radioactive iodine treatment. When the dose of radiation to the thyroid is very low, like might occur by accidental ingestion of litter box contents, then mutations leading to cancer can ensue. However, because your cat will be radioactive for several days after receiving the shot, precautions must be taken during and after the treatment. Amazingly despite over 35 years of veterinary experience treating hyperthyroid cats with radioiodine there are virtually no reported side effects. So excited we decided to go this route and cure her instead of just treating with daily medication. 2007 07/19/2011; Available from: http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/. Certain studies suggest that in some hyperthyroid cats, limiting the amount of iodine in the diet may be a viable option for treating this disease. Cats exclusively fed the prescription diet will remain normal, but if the diet is discontinued, they will once again become hyperthyroid. When a radioactive form of iodine is given to hyperthyroid cats, the radiation destroys a portion of the thyroid gland. There are no studies that directly link cancer to the low dose radiation used in current medical imaging. You can't visit Fluffy during his stay at the veterinary facility. Subscribe to always know when we add new material! This helps us offset the costs of running this site, so thank you for your support! Now that he's back home, he still exhibits the behavior of wanting food all the time but I wonder if it's a habit he picked up before treatment or perhaps the symptoms won't completely gone away until the treatment has time to take hold.