What is hyperthyroidism in cats?
Hyperthyroidism is a condition usually seen in cats middle-aged or older.
If your cat is suffering from hyperthyroidism their metabolism will speed up. This means that your cat will burn energy too quickly, resulting in weight loss even if you notice that your kitty is eating considerably more food than usual. They will also be restless and cranky, and may even drink more water and urinate more often.
What are the symptoms of hyperthyroidism in cats?
In the beginning, signs of hyperthyroidism in cats are usually subtle, and will gradually become more severe over time. Other underlying health issues can also complicate or mask symptoms of hyperthyroidism, so it’s important to see your vet early if your cat shows any of the symptoms listed below. Cats producing too much thyroid hormone may show one or more of the following symptoms:
- 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?
For most cats, hyperthyroidism is caused by a non-cancerous tumour located somewhere on the thyroid gland.
In rare cases, the tumour can develop into thyroid cancer.
What are long-term complications of hyperthyroidism?
Left untreated, hyperthyroidism can impact the function of your cat's heart and possibly lead to heart failure.
Your cat may also develop hypertension (high blood pressure) as a result of hyperthyroidism.
Hyperthyroidism and kidney disease often occur at the same time in older cats. When both these conditions are present, they need to be closely monitored and managed as managing hyperthyroidism can sometimes adversely affect kidney function.
How is hyperthyroidism diagnosed?
Diagnosing hyperthyroidism in older cats can be somewhat tricky. Your vet will complete a physical exam and palpate your cat’s neck area to look for signs of an enlarged thyroid gland.
Because there are a range of conditions that share the clinical symptoms of hyperthyroidism, a variety of tests may be used to diagnose your cat's condition.
A complete blood count (CBC) urinalysis and chemistry panel can help rule out kidney failure and diabetes. A simple blood test showing elevated T4 levels in the bloodstream may be enough for a definitive diagnosis. Your vet may also check your kitty’s blood pressure or perform an electrocardiogram, chest x-ray or ultrasound.
How will my vet treat my cat’s hyperthyroidism?
Depending on the results of your cat's tests, your vet may choose one of several treatment options for your cat’s hyperthyroidism. 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 hyperthyroidism be treated with a modified diet?
Hyperthyroidism in cats can often be managed through a diet for cats with hyperthyroidism, which is an iodine-restricted prescription diet from your vet.
Iodine intake is necessary for the production of thyroid hormones, so the goal of an iodine restricted therapeutic diet is to help reduce the production of thyroid hormones by reducing iodine in your cat's diet.
Strict adherence to the low-iodine diet is necessary for this treatment to be effective, which can prove challenging for some pet parents and their cats. Along with feeding your cat food for hyperthyroidism, you will need to strictly monitor your cat's treats, and prevent them from eating anything other than the specific iodine-restricted food.
Some studies show that after three weeks of following a prescription hyperthyroid diet, cat's thyroid hormone levels begin to decrease, and within a few months, they may even return to normal levels.
What is the prognosis for cats with hyperthyroidism?
If the condition is diagnosed and treated early, the prognosis for cats suffering from hyperthyroidism are generally good. In some cases where the condition has become more advanced, complications with other organs can worsen 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.