Anti-thyroid drugs act by reducing the production and release of thyroid hormone from the thyroid gland. Risks unrelated to radioiodine therapy: Cats treated with radioactive iodine for their hyperthyroidism have several risks unrelated to the radioiodine therapy itself. If the disease involves both lobes of the thyroid gland, two surgeries may be required, depending on the surgeon's choice of procedures. You may also be advised to suck on sour candy after treatment to help the radioactive iodine come out in your saliva. This single treatment will cure 95-98% of cats. And, if you destroy your thyroid gland, it turns out that that may have consequences on your metabolism. . Many older cats with overactive thyroids have actual enlargement of the gland which can be felt in the neck by your veterinarian. Because of these rare but serious side effect risks, your cat will need to be closely monitored by having simple blood tests performed every three to six months when using this medication. In most cases, only enough radioiodine is given to destroy that part of the gland that is functioning . This can be accomplished in several ways: Radioactive iodine therapy. Clinical signs include lethargy, dullness, obesity, oily skin, and matted fur. With your cat's diseased thyroid, after methimazole treatment failed, large doses of iodine might have proven effective. Surgical patients may become hyperthyroid again if abnormal cells are missed during surgery or if new abnormal cells develop. 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. It takes several weeks for methimazole to restore thyroid hormone levels to normal. Hence for a transient period following radioiodine therapy, the patient's urine contains excreted radioiodine which will emit beta particles as it continues to decay. There are several hypothesized causes of hyperthyroidism. In a study of 524 hyperthyroid cats treated with I-131, only 11/524 (2.1%) developed 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. 1. Treatment for Hypothyroidism in Cats. For example, some families cant medicate cats every day, so a more permanent solution such as radioactive iodine treatment or surgery may be best. The advantages of radioactive iodine therapy are that the procedure most often cures hyperthyroidism, has no serious side effects, and does not require anesthesia. Even after treatment it may take a long time to reverse weight loss and muscle loss that occurred before your cat's diagnosis. 3. The three ways that we control exposures to external sources of radiation are time, distance, and shielding. The study followed people for 26 years after two or more treatments. The treatment options for hyperthyroidism are: Oral medication. 2. Many times the only symptoms these other conditions cause are weight loss. Too cold? . 101(4 Pt 1): p. 717-9. 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. Studies have shown that cats treated with I-131 live longer than those treated with pills, added Mosenco, citing a study where I-131-treated cats lived an average of four to five years following treatment, versus an average of only two years for cats on medication.Dec 19, 2016. What are other nutritional concerns for my hyperthyroid cat? The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. Copyright 2023 Leaf Group Ltd. / Leaf Group Media, All Rights Reserved. If hypertension is diagnosed along with hyperthyroidism, drugs may be needed to control the blood pressure and reduce the risk of damaging other organs. 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. In some cases, the cat will develop a heart murmur associated with cardiomyopathy. The chronic elevation of circulating thyroid hormone levels in cats with hyperthyroidism leads to changes in their heart muscle that predispose them to developing heart failure. Depending on the dose, radioactive iodine can kill a portion, or all, of your thyroid. Why isn't there a study directly linking medical imaging and cancer? Subscribe to always know when we add new material! When an injection of radioactive iodine is given, it destroys the abnormal thyroid tissue without endangering other organs. The outcomes following most hyperthyroid therapies are usually excellent, and most cats have a very good chance of returning to a normal state of health. 8. Toxicology and Applied Pharmacology, 2004. Pediatrics, 1998. Follow up blood work is essential to ensure kitty does not become hypothyroid which is too little thyroid. The first step is determining the blood level of one of the thyroid hormones calledtotal thyroxine (TT4). GFR results are used to determine the functional status of the kidneys, and identify cats with subclinical renal disease. Miles K.G., Simpson S.A., Zimmerman R.B., et al. Calabrese E.J., Hormesis: From Marginalization to Mainstream: A Case for Hormesis as the Default Dose-Response Model in Risk Assessment. Upon discharge from PVESC (after an average of 4 to 7 days after treatment), treated cats will still be excreting radioiodine in their urine, saliva, and feces. 4. 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. What they are trying to prevent is the intake (ingestion, etc.) I-131 therapy does not require anesthesia and eliminates the need for daily medication. Clients owning hyperthyroid cats undergoing radioiodine therapy are always considered members of the general public. All rights reserved. In cats, an underactive thyroid is extremely rare. . Weight gain was similar for patients who received antithyroid drugs or radioiodine treatment but was significantly greater for patients who had been treated with thyroidectomy (5 kg vs 10 kg; P = 0.007). Amazingly despite over 35 years of veterinary experience treating hyperthyroid cats with radioiodine there are virtually no reported side effects. What are the risks of my cat becoming hypothyroid? Removal of the thyroid glands, called surgical thyroidectomy, is a relatively straightforward surgical procedure that has a good success rate. The "radiation badge" worn by x-ray techs for example is good for measuring external exposure to radiation but does nothing to measure intakes of radioactive materials which is the primary concern in the case of a cat treated with radioactive 131I. Usually, the TT4 level is so high that there is no question about the diagnosis (see the handout "Thyroid Hormone Testing in Cats"). Note that the reference above excluding licensee's from considering "exposure to individuals administered radioactive material" in their compliance with the NRC regulartions does not apply to animals. Looking for a convenient way to access your pets health records, refill prescriptions, view upcoming appointments and more? About 25% of cats with hyperthyroidism become hypertensive. A small number of cats will remain hyperthyroid after treatment, if this is the case your cat will need . The radioactive iodine is administered as a single injection . Of 135 patients with documented pubertal status . Some cats develop side effects from methimazole, such as vomiting, lethargy, anorexia, fever, liver damage, anemia, and a decrease in white blood cells. However once the diagnosis of hyperthyroidism has been made, and no other illnesses are identified, the motivation to perform further diagnostics, especially those that require the need for anesthetics or are invasive may be lost. The majority of cancers occur later in life and the average lifetime risk of dying from cancer is 25%. 2000-2023 TheCatSite.com. radioactive iodine All three treatments will reduce thyroid hormone levels and the signs of hyperthyroidism. The ALARA recommendation follows the classic "less is more" argument and hence adherence to this philosophy suggests that exposures to ionizing radiation should be minimized whenever possible. 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. The most common clinical signs of hyperthyroidism are weight loss, increased appetite, and increased thirst and urination. The 1-month level thyroid may be slightly high, low or normal. In more serious cases, surgical removal of the thyroid glands may be required. Surgical removal of the gland under general anesthetic was another option. 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. Since fewer than 2% of cats with hyperthyroidism have cancerous growths of the thyroid gland, treatment is usually very successful. The medication can be given life-long or to stabilize the cat before other treatment. It has to do with how important your thyroid is in regulating your metabolism and your weight. Treatment for hypothyroidism in cats is . He's radioactive, so it's not safe even for humans wearing protective clothing to spend too much time around him. Domestic airline pilots are exposed to an additional 2.2 mSv per year, about the same dose as a brain CT. As you can see from the table below, the estimated risk of developing cancer from exposure to 0.1 Gy (= 100mSv), while it varies with the age of the individual, is something less than 1% for adults. Want to read more information on feeding your pet? The good news is that there are many treatment options available to our hyperthyroid cats. Protein and Carbohydrate Sources of Home-cooked Pet Diets, Deborah E. Linder, DVM, MS, DACVIM (Nutrition), Diet-associated dilated cardiomyopathy: The cause is not yet known but it hasnt gone away, Too hot? However, since wild-caught flaked Alaskan salmon is the first ingredient, it provides a lot of moisture. I might even suggest using disposable gloves when handling the litter box duties and when caring for the cat during the isolation time. Clients frequently have the following 2 questions when considering radioiodine therapy for their cat's hyperthyroidism. However, these options tend to be expensive and not possible for all pet owners. So in this case the targeted radiation exposure is actually increasing survival for these patients. Jeff Brunette, CHP, Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. Thyroid hormone regulates the metabolic rate of an animal. Feeding Hyperthyroid Cats Iodine restriction may help; weight loss is a . 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. There are four treatment options for feline hyperthyroidism: medication, radioactive iodine therapy, surgery, and dietary therapy. Learn more about radioiodine therapy for hyperthyroidism, Learn about radioiodine therapy for thyroid carcinoma, Learn more aboutSamariumtherapy for primary or metastatic bone tumors. Jane Meggitt has been a writer for more than 20 years. Try mixing baby food chicken or turkey in with some Fancy Feast. A swollen or tender neck and feeling flushed. 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. To convert these to traditional units we have prepared a. It is given one to three times daily and must be continued for the remainder of the pet's life. Surgical removal of the affected thyroid gland(s) may be very effective. 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? You must log in or register to reply here. 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. It will take about a month for thyroid levels to return to normal in most cats. Tiki Cat Hanalei Luau Wild Salmon Wet Cat Food. This is because the parathyroid glands (responsible for calcium balance in the body) are near the thyroid gland and may be damaged or accidentally removed during surgery. The goal of hyperthyroidism treatment is to lower the levels of thyroid hormones in the body. We found out about the radioactive iodine treatment and after lots.of research decided this was the way to go. 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. Let's tackle the external exposure first as it is the simplest concept. For the same reasons as surgical treatment, your cat will likely be started on methimazole for about a month before radioactive iodine therapy. Ten patients (6.4%) had DS (Down Syndrome) and 33 (21.0%) had received ATDs before RAI ablation. Lifelong administration of methimazole can control the effects of an overactive thyroid gland. This is why one of the first signs of thyroid disease may be a change in weight weight gain if the thyroid is underactive and weight loss if the thyroid is overactive. The recommended food for cats with thyroid problems is high in protein yet low in carbohydrates, iodine (around 0.32 ppm) and phosphate. Diagnosis Excessive weight gain. J Vet Intern Med, 2001. Hyperthyroidism may also cause vomiting, diarrhea, and hyperactivity. under the skin, like a vaccine) and the radioactive iodine is quickly absorbed into the bloodstream. Cornell University College of Veterinary Medicine, Cornell Ruffian Equine Specialists, on Long Island, Cornell Veterinary Experts Address Feline Nutrition. Most of the extra radioactive iodine is eliminated in your urine. Hair loss. The veterinarian's recommendations are to isolate my cat for at least two weeks. AAFCO Doesnt Approve Pet Foods, A broken heart: Risk of heart disease in boutique or grain-free diets and exotic ingredients, Its Not Just Grain-Free: An Update on Diet-Associated Dilated Cardiomyopathy. That was part of the problem we had before treatment. A blood chemistry panel and urinalysis will provide information about other organs and provide your veterinarian with an overall picture of your cats health. 1. Radioactive iodine treatment is a therapy that your veterinary surgeon may recommend if your cat is diagnosed with hyperthyroidism. The remainder is gone in about the next two months or so. These tests are needed to evaluate your cats overall health and predict the likelihood of complications with the chosen treatment protocol. Other therapeutic monitoring. Radioactive Iodine Therapy Dr. Heinze is an employee of Mark Morris Institute and has provided professional serviceshas done consulting for Lafeber and WellPet, given sponsored talks for Nestl Purina PetCare and the Pet Food Institute, and provided professional services to Balance IT.com and Mark Morris Institute. Because of strict treatment guidelines, most facilities will not allow visitors during this quarantine period. Endocrinology, 1988. 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? Surgery or radioactive iodine therapy to regulate overactive hormone production can sometimes leave cats with the opposite problem: their levels of thyroid hormone are now too low. 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. 20.1301 Dose limits for individual members of the public. After treatment, the normal thyroid tissue will regain full function within 1-3 months. Your cat can receive methimazole, a medication that inhibits thyroid hormone production. 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. 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. During treatment, radioactive iodine is administered as an injection and is quickly absorbed into the bloodstream. All three have risks and benefits. 5. How does the risk from medical radiation compare to background radiation exposure? Copyright 2019 Advanced Veterinary Medical Imaging. Committee on Environmental Health. 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). 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. In cats > 95% of the radioiodine is excreted in the urine. If left untreated and unmanaged, these changes may eventually compromise the normal function of the heart and can even lead to heart failure. Surgery. Scaly skin. Hypocalcemia can be life-threatening and may require either short-term or long-term medication postoperatively should it occur. The effectiveness of this transdermal gel is acceptable in most cases. This can best be done by monitoring your cat's body condition, muscle condition, and weight. 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. What is the biggest concern with nuclear meltdown and why? People may take RAI . Radioactive iodine therapy is becoming the treatment of choice for felines with hyperthyroidism. Dietary Therapy This usually leads to permanent destruction of the thyroid, which will cure hyperthyroidism. I-131 is normally a health concern after the . The advantage of surgery is that it is likely to produce a long-term or permanent cure in most cats, and therefore eliminates the need for long-term medication.