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What is hyperthyroidism in cats?

Your cat's body relies on hormones to regulate all of the functions allowing them to live long, healthy lives. Sometimes there is a dysfunction, like with hyperthyroidism where there is too much hormone being produced. Our Cumming vets share some vital information about hyperthyroidism in cats like the symptoms, causes, and possible treatment options.

What is hyperthyroidism in cats and what is its effect on their body?

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.

Symptoms of Hyperthyroidism in Cats

While hyperthyroidism can affect any cat breed, it primarily afflicts older cats, typically those aged between 12 and 13 years. Both female and male cats experience an equal impact.

With hyperthyroidism in cats, the symptoms 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 the condition becomes more advanced, some cats will pant when they are stressed, which is unusual for cats. 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?

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.

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.

How is hyperthyroidism diagnosed?

Diagnosing hyperthyroidism in older cats can pose some challenges. Your vet will conduct a physical examination and examine your cat's neck area to detect signs of an enlarged thyroid gland. At Animal Medical Center of Cumming, 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 will my vet treat my cat's hyperthyroidism?

If hyperthyroidism occurs in cats, the treatment options may vary depending on their unique situation. Some of the potential treatments may include:

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

What is the expected outcome of feline hyperthyroidism?

If veterinarians diagnose and treat hyperthyroidism in cats early, they generally have a good prognosis. In cases where the condition has advanced, complications with other organs can worsen the prognosis.

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 Cumming vets today to book an appointment for your feline friend.

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