Feline Hyperthyroidism: Symptoms and Stages of Hyperthyroidism in Cats

Cat at Vet for Feline Hyperthyroidism

As a devoted cat parent, you know your feline friend better than anyone else. You've been there through the good times and the challenging moments, always striving to provide the best care possible. This close bond allows you to identify even subtle changes in their health and well-being. If you suspect your cat may be experiencing hyperthyroidism, a common endocrine disorder, this guide can provide valuable information. Understanding the signs, diagnosis, and treatment options will empower you to work with your veterinarian to ensure your cat receives the best possible care and maintains a good quality of life.

What is Hyperthyroidism in Cats?

Hyperthyroidism is an endocrine disease caused by the overproduction of hormones by the thyroid gland, a small, two-lobed organ located in the middle of the neck. These hormones help regulate the body's metabolism, affecting heat production and the body's use of nutrients like protein, carbohydrates, and fat. The main hormone produced by the thyroid gland is called thyroxine, or T4.

Endocrine systems are hormone-secreting organs. Other examples of endocrine diseases are diabetes mellitus, which is caused by a malfunctioning pancreas, and hyperadrenocorticism, also known as Cushing disease, which is caused by malfunctioning adrenal glands.

Hyperthyroidism is the most common endocrine disease of cats. Hyperthyroidism can also occur in people and is called Grave's disease or toxic nodular goiter.

Causes of Feline Hyperthyroidism

Hyperthyroidism in cats is most commonly caused by an enlargement of the thyroid or a noncancerous thyroid tumor. In rare cases, it can also be caused by thyroid gland cancer.

While the exact cause of feline hyperthyroidism is not fully understood, researchers believe that certain environmental factors may play a role. Chemicals found in flame retardants are being studied for their potential connection to hyperthyroidism in cats exposed to high levels. Other factors that may contribute to the development of the condition include certain types of cat litter, canned food, and fish flavors in food.

Breeds Least Affected by Hypothyroidism

While the cause for this association is not fully understood, some studies suggest certain factors may increase the risk of developing hyperthyroidism in cats. Cats with long hair appear to be more susceptible to the condition compared to their short-haired counterparts. Additionally, female cats and mixed-breed felines may have a higher chance of developing hyperthyroidism.

It's interesting to note that some cat breeds seem to have a lower risk of developing hyperthyroidism , including Siamese, Burmese, Persian, British Shorthair, Abyssinian, and Tonkinese. This doesn't mean these breeds are immune, but it suggests a possible genetic influence.

Early detection is crucial for all cats. If you notice any changes in your cat's behavior or appetite, schedule a visit with your veterinarian for a proper diagnosis. Early detection and treatment can significantly improve your cat's quality of life and prevent potential complications.

Symptoms of Hyperthyroidism in Cats

Hyperthyroidism can manifest in various ways, and some signs might be subtle at first. However, being familiar with the common symptoms allows for early detection and treatment, significantly improving your cat's well-being. Here's a list of signs to watch out for:

  • Weight loss despite an increased appetite

  • Restlessness and hyperactivity

  • Increased vocalization, especially at night

  • Increased thirst and urination

  • Vomiting and diarrhea

  • Unkempt or matted coat

  • Rapid heartbeat and breathing

  • Muscle weakness or lethargy in late-stage hyperthyroidism.

  • A lump on the cat's neck where the thyroid gland is located may also be noticeable.

Complications of Feline Hyperthyroidism

If left untreated, hyperthyroidism can lead to serious health issues in cats. The increased hormone levels can affect the heart, causing altered rhythm, murmurs, and a rapid heart rate. This can lead to heart disease and high blood pressure. Cats with untreated hyperthyroidism may experience trouble breathing, coughing, and collapse due to these complications.

Diagnosing Hyperthyroidism in Cats

To diagnose hyperthyroidism, your veterinarian will perform a complete blood count and chemistry panel to assess your cat's overall health and check for signs of dehydration and liver changes. Thyroid tests will be run to measure the levels of T4 in the blood. If these tests are normal, but your vet still suspects hyperthyroidism, additional thyroid hormone tests, such as a T3 suppression test, may be conducted.

Depending on the severity of your cat's condition, your veterinarian may also recommend X-rays and an ultrasound to evaluate their heart and other organs.

Treatment Options for Feline Hyperthyroidism

Medications: The most common treatment for hyperthyroidism in cats is the use of anti-thyroid drugs like methimazole, usually given twice daily in pill form. Compounded oral liquids or topical medications applied to the inside of the ear may also be available. Regular blood tests will be necessary to monitor T4 levels and ensure the proper dosage. Thyroid medication will need to be given for the rest of your cat's life.

Prescription Diets: Special prescription diets, such as Hill's y/d, are available for cats with hyperthyroidism. These diets work by reducing the amount of iodine consumed, as iodine is necessary for the thyroid gland to produce T4. While prescription diets can be effective, they may not work for all cats and can be expensive. They are also not recommended for cats with certain other health issues, like kidney disease.

Surgery: Surgical removal of one or both thyroid gland lobes may be an option for some cats. Before surgery, thyroid medication is usually given to ensure the heart and circulatory system are healthy enough for the procedure. Thyroid gland removal is a delicate surgery and may require a specialized surgeon. Some cats may require medication for hypothyroidism after surgery, as the thyroid gland will no longer be producing hormones.

Radioactive Iodine Therapy: Considered the best way to cure hyperthyroidism, radioactive iodine therapy involves the injection of radioactive iodine, which targets and destroys the diseased thyroid tissue without harming the surrounding structures. This treatment is safer and more effective than surgery but can only be performed at specialized veterinary institutions and is more expensive. Following treatment, your cat will need to remain hospitalized for several days to weeks until the radioactive material has cleared from their body. During this time, they will need to be isolated due to their radioactivity.

Cat Eating Prescription Diet for Feline Hyperthyroidism

Cost of Treating Feline Hyperthyroidism

The cost of treating feline hyperthyroidism varies significantly depending on the chosen treatment method. Initial diagnosis typically falls within the range of $75 to $350. Medication costs can range from $20 to $50 per month, depending on the specific prescription. Additionally, if a special prescription diet is recommended, expect to pay $30 to $90 per month depending on the amount and type of food needed.

For a more definitive solution, surgical removal of the affected thyroid gland or radioactive iodine therapy are options, but they also carry a higher price tag. Surgical intervention can range from $750 to $3,000, while radioactive iodine therapy typically falls between $2,500 and $3,000 for the procedure itself. It's important to note that these costs might not include additional expenses like pre-surgical testing, boarding during treatment, or follow-up care. Finally, recheck T4 testing, usually around $50, is typically needed only once or twice a year after the optimal treatment plan is established.

Remember, discussing treatment options and associated costs with your veterinarian is crucial to making the best decision for your cat's health and your budget.

How to Afford Treating Hypothyroidism in Cats

The cost of treating feline hyperthyroidism can be substantial, but cat insurance can help alleviate the financial burden, including the costs of diagnostic tests, medications, and treatments for conditions like hyperthyroidism.

Optional wellness plans can help budget for routine care, such as annual check-ups and blood work, which can aid in the early detection and management of thyroid issues in cats. If you don't have pet insurance, some veterinary clinics offer financial assistance programs or payment plans to help make treatment more affordable.

Life After a Diagnosis of Hypothyroidism in Cats

Receiving a diagnosis of hyperthyroidism for your cherished cat can be challenging, but it's important to remember that you're not alone in this journey. With the guidance of your veterinarian and a deeper understanding of this common feline endocrine disorder, you can make informed decisions about your cat's care and treatment.

While the exact cause of hyperthyroidism in cats is not yet fully understood, providing your feline companion with a healthy environment, a balanced diet, and regular check-ups can help with early detection and management. If you suspect your cat may have hyperthyroidism, reach out to your veterinarian for support and guidance. With proper treatment and care, many cats with hyperthyroidism can go on to live happy, healthy lives, continuing to bring joy and love into your home for years to come.