What is hyperthyroidism?

The thyroid gland, located in your cat’s neck, uses dietary iodine to make thyroid hormones that help regulate important body functions including your cat’s:

  • Metabolism
  • Body temperature
  • Blood pressure
  • Heart rate
  • Gastrointestinal (bowel) function

Hyperthyroidism is a common feline endocrine disorder, most often diagnosed in older cats over age 10. Left untreated, hyperthyroidism can have serious, sometimes fatal, consequences on vital organs like the heart and kidneys. The good news is, this disease is highly manageable and can be controlled with proper veterinary care.

If your cat has hyperthyroidism, her thyroid gland will be enlarged and produce excessive amounts of thyroid hormone. Left untreated, hyperthyroidism can have serious, sometimes fatal, consequences on vital organs like the heart and kidneys. The good news is, this disease i,s highly manageable and can be controlled with proper veterinary care.

Warning Signs and Symptoms of Feline Hyperthyroidism

Signs of hyperthyroidism can vary in severity depending on how long a cat has been ill. If your cat exhibits any of the following signs, contact your veterinarian immediately:

  • Weight loss
  • Increased appetite
  • Diarrhea and/or vomiting
  • Increased thirst
  • Poor skin and coat condition
  • Hyperactivity

Cats with chronic kidney disease and diabetes mellitus exhibit some signs similar to hyperthyroidism. Your veterinarian may also need to perform tests for these diseases to ensure an accurate diagnosis. If your cat has hyperthyroidism, her thyroid gland will be enlarged and produce excessive amounts of thyroid hormone.

Managing hyperthyroidism

Four potential options for managing cats with hyperthyroidism are:

  1. Daily nutrition: limiting dietary iodine intake reduces thyroid hormone production
  2. Daily medication: anti-thyroid drugs inhibit the production of thyroid hormones
  3. Radioactive iodine therapy: radiation to treat abnormal thyroid tissue
  4. Surgery: removal of diseased thyroid tissue

Treatment: The importance of nutrition

The food your cat eats plays an important role in her overall health and well-being. Balanced nutrition is an essential part of an active, healthy lifestyle. For accurate diagnosis and treatment options, always consult your veterinarian and ask them to recommend the best food for your cat’s thyroid health.

Check out this video about how Prescription Diet cat food can help.

Thyroid Health Questions to Ask Your Veterinarian

  1. What does the thyroid gland do and how can it impact the health of my cat?
  2. What are the different therapy options if my cat has thyroid health problems?
    • What factors do you consider before deciding the best way to manage this condition?
    • What if my cat has other health issues? How will that affect your therapy recommendation?
  3. What are the pros and cons of surgery or radioactive iodine therapy?
    • How will any potential complications be managed?
    • Where will the surgery or radioactive iodine therapy be performed?
    • How long before I can bring my cat home?
    • What do I need to know when I do bring my cat home?
    • Is there a chance the thyroid health problem will come back after either of these procedures?
  4. If anti-thyroid medication is recommended, how often will I have to medicate my cat?
    • What is the best way to administer the medication?
    • How long will my cat have to take the medication?
    • Are there potential side effects? How can these be managed?
  5. Can nutrition be used to manage thyroid health problems? Would you recommend a Hill’s® Prescription Diet® cat food for my cat’s thyroid health?
    • How do I transition my cat from her current food to the Prescription Diet® cat food?
    • Will I have to feed this food for the rest of my cat’s life?
    • Can I still give my cat treats? How will other medications or supplements affect the effectiveness of the nutrition?
    • Can my other cats eat this food? How do I make sure each of my cats eat the right food?
  6. How often will I need to bring my cat back to the clinic for check-ups?
    • What kinds of things will you be monitoring during these recheck appointments?
  7. What is the best way to reach you or your hospital if I have any follow-up questions?
    • Ask if you need a follow-up appointment
    • Ask if a reminder email or notice will be sent
Hills Author Hills Author
Staff Author

One of our staff authors prepared this article for you

Related articles

Cat Food Ingredients: What Should Go Into Your Cat's Food?

Unsure which ingredients are important to your cat's diet? Learn which types of cat food ingredients are necessary and how they benefit your cat's health.

Cat Metabolism: How it Affects Your Feline Friend

Learn from a Veterinarian: Discover how your cat's metabolism can affect her health, including weight fluctuations, and how metabolic cat food can help.

Benefits of Neutering a Cat

Learn about when the best time to spay or neuter your cat is, and the health benefits that accompany the surgery.

Cat Zoomies: Why Your Cat Gets Them & When to Call the Vet

Learn why your kitty gets cat zoomies, random bouts of energy that cause them to race through the house, and when zoomies could indicate a health issue.

Ways to Maintain Your Cat's Healthy Coat

Learn the visual signs that your cat is healthy including what to look for in her skin, ears, and eyes, as well as as signs you should call your vet about.

Keeping Your Cat Hydrated if She's Not Drinking Water

Learn why your cat is drinking less water than she used to, how much she should be drinking, and how to recognize and prevent her from getting dehydrated.

What Is My Cat's Body Language Telling Me?

Learn to decipher your cat's numerous non-verbal language queues, including the meanings behind expressions through her eyes, ears, tail and stance.

Reasons for Your Cat Vomiting

Learn the different causes of cat vomiting, from throwing up common hairballs to more serious health concerns, and how grooming & food can help prevent it.

Causes & Signs of Dental Disease in Cats

Recognize the importance of proper dental hygiene in your cat's overall health. Learn about causes of dental disease, and questions you should ask your vet.

DIY Cat Stain & Odor Remover That Actually Works

Learn how to make your own DIY cat stain remover, as well as how to remove cat odors from your home.

Recognizing Cat Obesity, Causes and Signs

Feline obesity puts cats at higher risk of several health concerns. Here's how to tell if you have an overweight cat so you can intervene early.

Cat Language: How Cats Communicate

Learn how your cat communicates with you as well as other cats in the house, and what their cat language might be telling you about them.

Knowing Your Cat's Special Anatomy

To provide the best care for your cat, it is important to know as much about them as possible. Read about a cat's specialized anatomy to learn more.

7 Tips for Newborn Kitten Care

Learn helpful care tips for your kitten in their first four months, including essential topics like bedding, food, using the litter box, grooming & more.

Why Do Cats Hate Water?

Discover the common reasons why cats don't tend to like water or getting wet, and better learn about their curious fascination with running water.

Fun DIY Beds for Your Cat

Learn how to create four different DIY cat beds that will provide your furry friend with a cozy space of her own & won't break your bank!

How to Talk to Cats (and Are They Really Listening?)

Learn tips for talking & communicating with your cat, including suggested gestures like blinking, as well as how to tell if they are actually listening.

Home Dental Care Methods for Your Cat

Use these 4 steps on how to properly brush and provide the right dental care for your cat's teeth.

Do Cats Fart?

While it may not be common, cats to indeed pass gas. Learn how your cat's food impacts their gassiness and whether you need to be concerned.

Your Cat Needs Attention? Here's What She'll Do to Get It.

When a cat wants attention, she'll pull out all the stops until she grabs your interest, such as these seven classic behaviors guaranteed to distract you.