Hyperthyroidism in Cats – Signs, Symptoms, & When to See a Vet

As cats get older, they’re prone to more health issues. One of the most common in older cats is hyperthyroidism, which is a type of endocrine disorder that affects the thyroid gland and leads to an overproduction of thyroid hormones. This condition can cause a range of health issues, including rapid weight loss, increased appetite, hyperactivity, and heart problems.

While hyperthyroidism is manageable or even curable with proper treatment, early detection can help prevent serious complications. If you can identify the signs and symptoms of hyperthyroidism early enough, you can seek veterinary care and help your furry friend get the help they need. By understanding this condition, you can help make sure your cat stays healthy and comfortable throughout their senior years.

What is Hyperthyroidism in Cats?

Hyperthyroidism is a condition where the thyroid gland, located in the neck, becomes overactive and produces too much thyroid hormone (thyroxine). This hormone plays an important role in regulating your cat’s metabolism, which affects everything from energy levels to organ function.

In most cases, hyperthyroidism is caused by a benign (non-cancerous) tumour on one or both of the thyroid glands. This tumor leads to an overproduction of thyroid hormones, which causes your cat’s metabolism to speed up, which can lead to various symptoms.

Although hyperthyroidism is more common in older cats, it can occur in younger cats too. Early diagnosis and treatment are key to managing hyperthyroidism and helping maintain a good quality of life for your cat. However, if left untreated, the condition can lead to serious complications, including heart disease, high blood pressure, and kidney damage.

Common Signs & Symptoms to Look Out For

There are various noticeable signs to look out for which will help you identify hyperthyroidism in your cat. As the thyroid hormone levels increase, your cat’s metabolism will speed up, causing changes in their behavior, appetite, and overall health.

Despite eating more, hyperthyroidism affects how cats put on weight. You may notice they are suddenly eating excessively but are losing weight rather than putting it on. Your feline may also seem exceptionally thirsty and is urinating more frequently. As per the PDSA, your cat may also start exhibiting noisy and demanding behavior or seem lethargic and tired.

In some cases, you may notice one or two small lumps on your cat’s neck or that your cat has a very fast heartbeat or is panting, even if they are lying or sitting still. Your cat may also have a dry or untidy coat or hair loss, particularly on their tail.

Some cats may experience gastrointestinal issues too like vomiting, diarrhea, or an upset stomach as a result of the hormone imbalance.

Causes & Risk Factors of Hyperthyroidism

The most common cause of hyperthyroidism in cats is the growth of non-cancerous tumors called adenomas on their thyroid glands. These tumors cause the glands to overproduce thyroid hormones, which leads to a faster metabolism. In rare cases, hyperthyroidism may also result from cancer, but this is less common.

Hyperthyroidism is more frequent in older cats of either gender, typically those over the age of 10. As the cat gets older, the risk increases, although younger cats can sometimes suffer from hyperthyroidism too.

Any breed of cat is susceptible to hyperthyroidism, but certain breeds, such as Siamese and Burmese, may have a higher chance of developing it.

When to See a Vet

If you notice any of the symptoms listed above, you should contact your vet as soon as possible to express your concerns. Even if your cat isn’t showing any noticeable signs, you should still seek advice from your vet as catching the illness early could significantly help your cat’s health. You know your cat best, so trust your gut if you think they may be suffering or could be developing a health issue.

Having a suitable pet insurance policy that covers ongoing health conditions from insurers such as Petgevity can help you cover vet bills and medication for your beloved pet. While not common, you can also get insurance for pre-existing health conditions (such as hyperthyroidism), which covers your cat even if they already have the condition. It’s best to research different policies to ensure you find one that suits you and your cat's exact needs.

Treatment Options for Hyperthyroidism

As per the Blue Cross, hyperthyroidism in cats is easily treated with a daily dose of anti-thyroid medication. It works by blocking the thyroid gland’s ability to produce excess thyroid hormones and can provide immediate relief of symptoms. While the anti-thyroid medication won’t cure the condition, it can help keep it under control and let your cat live a long, happy life.

The medication is available in liquid and tablet form and is typically administered two or three times throughout the day at regular intervals. Your cat will also need regular trips to the vet so that their condition can be monitored.

In some cases, the solution is surgery. The affected tissue is surgically removed in an operation called thyroidectomy, which can provide a long-term or permanent cure. While this option is suitable for cats with a single thyroid tumor, it might not be an option if your cat has cancer or if both their thyroid glands are affected. And, as with any invasive surgery, there are risks associated with anesthesia, particularly for older cats.

As per The Hyperthyroid Cat Centre, radio-iodine therapy is typically the best low-risk permanent cure for cats. This treatment involves injecting a small, controlled amount of radioactive iodine into the cat’s bloodstream. The iodine is absorbed by the thyroid tissue, where it destroys the overactive thyroid cells while leaving the rest of the thyroid and surrounding tissues unharmed. It has minimal side effects and there’s no need for long-term medication. However, it is an expensive solution and may not be suitable for cats with other serious health conditions like kidney disease or heart problems.

Managing Hyperthyroidism at Home

While it can be scary to hear your beloved pet has an issue with their thyroid gland, you can help your cat lead a comfortable, healthy life with the right care. Once your cat is diagnosed with hyperthyroidism and treatment is underway, managing the condition at home is an important part of caring for their well-being.

If your cat is on medication, it’s essential that you give the prescribed dose consistently and on time. This could be in the morning, lunchtime and evening, or whatever frequency your vet advises you to give the medication. You should monitor your pet for side effects such as vomiting or changes in their appetite, as this could be a sign that the medication dosage needs adjusting.

Keeping Your Cat Healthy & Happy

You’ll want to keep your cat healthy while managing their hyperthyroidism, so it's important to follow your vet's treatment plan, whether that involves medication, diet changes, or other therapies. Monitoring your cat’s weight, symptoms, and behavior regularly, will ensure they receive proper nutrition with a consistent feeding schedule.

It’s important to get your cat regularly checked by the vet so they can adjust treatments or check for any complications. By monitoring your furry friend and checking for symptoms, you can help your cat live a healthy, happy life.