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Feline Hyperthyroidism

Your veterinarian has diagnosed your cat with hyperthyroidism.  What can be done to help your furry friend?

First, let’s learn a bit more about the condition. Feline hyperthyroidism is the most common endocrine disorder in middle aged and geriatric cats. Symptoms can include behavioral changes, hyperactivity, weight loss, increased appetite, increased thirst and urination, vomiting, diarrhea, and rapid heart rate. Often affected cats may have an unkempt coat that appears matted and/or greasy. Most cats respond quite well to treatment and have a good prognosis. Cats with severe disease or those that have developed further complications may have a more guarded prognosis.

Your veterinarian may diagnose hyperthyroidism through physical examination as well as through routine laboratory findings indicating elevated thyroid hormone levels in the blood.  Once a diagnosis of hyperthyroidism is made, your veterinarian will discuss options for treatment, which may include anti-thyroid medications, diet, surgery or radioactive iodine (I-131).

How Do I Know if Radioactive Iodine is the Right Treatment for My Cat?

Your veterinarian can help you decide if radioactive iodine (oftentimes called I-131) is a good option for your cat.  If so, a few pre-screening tests will need to be performed prior to administering the treatment.  These tests allow for further evaluation of the severity of the disease and determine if any other organ systems are involved.  These screening tests include: 

  • blood chemistry profile to screen for underlying illnesses such as kidney disease.  This routine blood test can be performed by your veterinarian. 
  • urinalysis is an additional screening test for kidney disease that can be performed by your veterinarian. 
  • thyroid scan (nuclear scintigraphy) is performed at Animal Imaging to evaluate the thyroid itself and give us a better understanding of the disease.  The thyroid scan will allow us to evaluate how much of the thyroid gland is affected and help us determine if the disease is benign or malignant 
  • Chest and abdominal radiographs (x-rays) are also performed at Animal Imaging as part of the thyroid work up to screen your cat for any overt problems with the heart, lungs or abdominal organs that may warrant additional diagnostics prior to treatment.

Once these tests are completed, our board-certified radiologists can determine if your cat is a good candidate for the treatment of hyperthyroidism with radioactive iodine.  If so, Animal Imaging can provide this safe and effective treatment in a comfortable environment.   

What is involved with radioactive iodine treatment? 

The treatment involves a subcutaneous injection (under the skin, like a vaccination) of the radioactive iodine.  Your cat will then need to stay in the comfort of our special kitty room until the level of radiation is low enough for your cat to safely return home (5 days).  The accommodations are comfortable and quiet.  You may and are encouraged to bring an item or two from home to give your cat a sense of familiarity; however, these items will not be returned to you following your cat’s stay as they continue to remain radioactive.  Many of our cat patients arrive with an old t-shirt or pillowcase that will no longer be needed at home.  You are also encouraged to bring your cat’s regular diet.  Our goal is to keep our patients as comfortable and happy as possible during their stay with us.   

When Your Cat Returns Home  

Once your cat is discharged, there are a few minor precautions listed below that will need to be followed in order to keep you and your family safe, as your cat will still have a low level of radioactivity for an additional two weeks post discharge.  Keep in mind these are temporary changes and in a short period of time you can return to your normal daily routine.  It is important to follow the precautions below for two weeks after discharge: 

  • Your cat should be confined in your home at all times.  This is the case even for cats who are otherwise primarily outdoors.   
  • Limiting your cat to a room in your home not frequently used, such as a guest bedroom or bathroom is strongly recommended.  This will limit your exposure to radioactivity.  Adult exposure should be limited to 20 minutes per person, per day.  Kissing your cat and/or allowing your cat to lick your face should be avoided.  Always wash your hands after contact with your cat or its litter.   
  • No persons under the age of 18 or any pregnant woman should come in contact with your cat.   
  • Your cat should not come into contact with any other household pets during this time. 
  • A separate litter box, food and water bowls should be provided for your cat.  Scoop the litter each day into a plastic bag and dispose of the sealed bag in an outside trash can not accessible by any children.  A litter box liner may also be used.  The person cleaning the litter box should wear disposable gloves. 
  • If your cat happens to vomit or soil outside of the litter box, household cleaners may be used.  Please be sure to wear gloves and dispose of the cleaning materials in the same manner as you would the litter.   
  • At the end of the two week period, discard any remaining litter and clean the room.  You and your cat may now return to your normal routine.   

Comments (3)

  1. Hello, I know you are closed today. Yesterday my vet said my 10 year old cat has feline hyperthyroidism. He mentioned radioactive iodine therapy. I am trying to figure out what to do. Can you tell me how much this treatment costs?

  2. Which form is the referral form that our vet needs to fill out for Hyperthyroid Radioactive Treatment?

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Animal Imaging – Veterinary Radiology

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