Skip to Main Content
Ask About Financing

Prognosis for Cats With Hyperthyroidism

When the glands that regulate bodily functions and organs aren't working properly, it can lead to serious implications. Here, our veterinary internists in Cumming talk about the impact of hyperthyroidism in cats and how internal medicine can help manage and even cure their condition.

How long can cats live with hyperthyroidism?

Unfortunately, hyperthyroidism in cats can be fatal if left untreated. This happens because the thyroid affects the function of nearly every organ in the body.

With early diagnosis and treatment, you can expect your cat to recover and live a long and healthy life. The treatment will depend on your cat's specific situation. We will discuss these in more detail later in this post.

Is hyperthyroidism in cats painful?

Pain itself is not typically a symptom of hyperthyroidism. Even so, cats affected by hyperthyroidism usually develop uncomfortable symptoms that worsen as the condition advances.

If your cat is suffering from hyperthyroidism you may notice weight loss, increased appetite, and increased thirst and urination. Hyperthyroidism may also cause vomiting, diarrhea, and hyperactivity and their coat may appear unkempt, matted, or greasy.

What happens if hyperthyroidism goes untreated in cats?

Because the thyroid glands produce hormones that help regulate the function of the vital organs, cats with untreated hyperthyroidism may develop secondary problems, including heart disease and high blood pressure.

When the level of thyroid hormones increases, your cat may experience heart issues such as an increased heart rate, stronger contraction of the heart and thickening of the left ventricle of the heart. If continued to be left untreated, this can end with eventual heart failure.

Hypertension, or high blood pressure, may also be a result of unmanaged hyperthyroidism, potentially causing damage to several vital organs, including the eyes, kidneys, heart, and brain.

What can you give a cat for hyperthyroidism?

If your cat has been diagnosed with hyperthyroidism then you may wonder if there's something you can give them to make everything better. While there are some things you can do at home including dietary changes and administering medications, certain cases will require veterinary treatments and care.

There are four main treatment options for hyperthyroidism in cats. They are:


Your vet may recommend anti-thyroid medications to help reduce the production and release of the thyroid hormone. While this cannot cure the condition, it can help regulate it, allowing your cat to live life more comfortably.

While this medication is considered inexpensive, it may cause several side effects like vomiting, fever, anemia and lethargy. You will also need to administer this medication twice daily which may be a difficult schedule to keep up with.

Your cat will require regular veterinary exams to track treatment as well as diagnostics to monitor kidney function.

Radioactive Iodine Therapy

Radioactive iodine therapy is the most common type of treatment for cats experiencing hyperthyroidism.

To perform this treatment, your vet will inject radioactive iodine into your cat, which will be quickly absorbed into the bloodstream. This iodine makes its way to the thyroid gland where the radiation will destroy any abnormal thyroid tissue without damaging the surrounding tissues. After about two weeks your cat's hormone levels should be close to normal again and your cat may be cured after about three months.

The main benefit of this treatment is that it allows for your cat to be fully cured of hyperthyroidism. However, it may not be available at all veterinary clinics as it requires the handling and injection of a radioactive substance and the clinic would need to be specially licensed to use radioisotopes.

The resulting radioactivity will have no negative effect on your cat, but there will need to be measures to protect those who may come into contact with them. This means that your cat will need to stay in quarantine at the clinic for about three to five days after treatment.


In some cases, the vet may recommend the removal of the thyroid glands. This is called a surgical thyroidectomy. Some of the advantages of this surgical procedure are that it has a high success rate and is considered likely to cure hyperthyroidism in cats.

The surgery itself will require anesthesia which can be dangerous for senior cats, young cats or those with medical issues. There is also a risk of unintentional damage to the parathyroid glands, which are located near the thyroid gland and are crucial in maintaining stable blood calcium levels.

Because of these risks, radioactive iodine therapy is considered more often than surgery.

Dietary Therapy

Certain studies show that there may be some success with treating cats using a diet that is low in iodine. This may be considered if your cat has a medical condition that prevents the use of other treatments.

Even so, reducing iodine may have other negative implications that cause serious harm and this option should always be discussed in full with your vet before beginning.

Veterinary Internal Medicine in Cumming

Veterinary internal medicine involves treating diseases and disorders of animals' internal systems including the endocrine system (hormone-producing glands).

At Animal Medical Center of Cumming, we have a variety of diagnostic tools and treatment methods at our disposal.

We can manage patients with multiple diseases or disorders, and provide effective treatment alternatives for those who do not respond well to standard procedures.

If your pet is exhibiting symptoms of an internal condition, our internal medicine veterinarians in Cumming will perform a thorough physical exam to diagnose the problem and develop a detailed treatment plan tailored to their specific needs.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

If your cat is showing the signs and symptoms related to hyperthyroidism our team can help. Contact our veterinary internists in Cumming today to book an appointment for your feline friend.

New Patients Welcome

Animal Medical Center of Cumming is accepting new patients! Our experienced vets are passionate about the health of Cumming companion animals. Get in touch today to book your pet's first appointment.

Contact Us

Book Online (770) 886-8555