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What is hyperthyroidism in cats?

The thyroid is a gland responsible for producing hormones that assist with the function of the body. An excess of these hormones is referred to as hyperthyroidism. Today, our Turlock vets talk about hyperthyroidism in cats including diagnosis and treatment options.

What is hyperthyroidism in cats?

The thyroid glands reside in your cat's neck and produce a range of hormones that regulate numerous body processes and control your cat's metabolic rate. If the thyroid gland produces an excessive or insufficient amount of these hormones, your cat will actively display symptoms of either hypothyroidism (insufficient hormone levels) or hyperthyroidism (excessive hormone levels).

In the case of hyperthyroidism, your cat's metabolism will actively accelerate. This means your cat will burn energy too rapidly, resulting in weight loss, even if you observe that your kitty is consuming considerably more food than usual.

What are the symptoms of hyperthyroidism?

While hyperthyroidism can affect any cat breed, it primarily afflicts older cats, typically those aged between 12 and 13 years. Male and female cats are equally at risk of developing this condition.

The symptoms of hyperthyroidism in cats often start subtly but progressively worsen over time. Additionally, other underlying health problems can complicate or conceal these symptoms. Therefore, it is crucial to consult your veterinarian promptly if your cat displays any of the following symptoms, indicative of an excess of thyroid hormone production:

  • Increase in thirst
  • Irritability
  • Restlessness
  • Mild diarrhea and vomiting
  • Increase in heart rate
  • Poor grooming habits
  • Hearty or increased appetite
  • Low heat tolerance 

When advanced, hyperthyroidism can cause cats to pant when stressed. Although most cats suffering from hyperthyroidism have a good appetite and are restless, others may feel weak, lethargic or experience a lack of appetite. 

What causes hyperthyroidism in cats?

A non-cancerous tumor located somewhere on the thyroid gland most often causes hyperthyroidism. However, in rare cases, the tumor can progress into thyroid cancer.

How can hyperthyroidism be diagnosed?

If your cat is older then diagnosing hyperthyroidism may be difficult. Your vet will conduct a physical examination and examine your cat's neck area to detect signs of an enlarged thyroid gland. At Community Veterinary Clinic, our veterinary team employs diagnostic testing to diagnose your pet's condition and deliver advanced care.

Because several conditions share the clinical symptoms of hyperthyroidism, various tests may be employed to diagnose your cat's condition. A complete blood count (CBC), urinalysis, and chemistry panel can help eliminate kidney failure and diabetes as potential causes. A straightforward blood test that reveals elevated T4 levels in the bloodstream may suffice for a definitive diagnosis. Your vet may also assess your cat's blood pressure or conduct an electrocardiogram, chest x-ray, or ultrasound.

How to Treat Hyperthyroidism in Cats

Depending on the specifics of your cat's conditions they can be treated in several different ways. They may include:

  • Radioactive iodine therapy (likely the safest and most effective treatment option)
  • Antithyroid medication
  • Surgery to remove the thyroid
  • Modified diet

How can a modified diet help manage my cat's hyperthyroidism?

Cats with hyperthyroidism can often manage the condition by following a prescription diet with restricted iodine, prescribed by your vet. Thyroid hormones require iodine for their production, so the therapeutic diet with reduced iodine aims to decrease the production of thyroid hormones in your cat's body.

To ensure the effectiveness of this treatment, it is crucial to adhere strictly to the low-iodine diet. This can be challenging for some pet parents and their cats. In addition to feeding your cat the prescription food, you must closely monitor your cat's treats and prevent them from hunting for their meals outdoors.

Studies indicate that following a prescription hyperthyroidism diet for three weeks can lead to a decrease in thyroid hormone levels. Within a few months, these levels may even return to normal.

How long do cats with hyperthyroidism live?

If diagnosed early and properly managed, cats with hyperthyroidism can live for many years with a very good quality of life.

What are the long-term complications of hyperthyroidism?

If left untreated, hyperthyroidism can affect your cat's heart function and potentially lead to heart failure. Hyperthyroidism may also induce high blood pressure in your cat. Although we observe this less frequently, high blood pressure in cats is associated with other severe health issues, including brain, kidney, heart, and eye damage. If your kitty is diagnosed with hypertension in addition to hyperthyroidism, they will require medication to control their blood pressure.

In older cats, hyperthyroidism and kidney disease often coexist. When both of these conditions are present, they require close monitoring and management, as the management of hyperthyroidism can sometimes negatively impact kidney function.

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 suffering from hyperthyroidism, our vets can help. Contact our Turlock vets today to book an appointment for your feline friend.

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