Hyperthyroidism is a common condition in older cats where the thyroid glands, located in the neck, produce too much thyroid hormone. This overproduction accelerates your cat’s metabolism, leading to a variety of health issues.
It’s most frequently seen in cats over the age of ten, but it can occur in younger cats as well. Early detection and proper treatment are essential to managing hyperthyroidism and ensuring your cat remains healthy and comfortable.
Causes of Hyperthyroidism in Cats
Primary Causes
The most common cause of hyperthyroidism in cats is a benign (non-cancerous) tumour on one or both of the thyroid glands, known as an adenoma. This tumour causes the thyroid glands to enlarge and produce excessive amounts of thyroid hormones.
Although these tumours are usually non-cancerous, they significantly disrupt the body’s normal regulation of metabolism.
Other Causes
In rare cases, hyperthyroidism in cats can be caused by a malignant (cancerous) tumour called thyroid carcinoma. While this is much less common, it can lead to more severe symptoms and may require different treatment approaches.
Environmental factors and diet have also been suggested as potential contributors, though the exact cause of hyperthyroidism remains not fully understood.
Recognising the Symptoms of Hyperthyroidism
Common Symptoms
The symptoms of hyperthyroidism can be quite noticeable, particularly if your cat is usually calm and easy-going. One of the most common signs is weight loss, even though your cat may have an increased appetite and eat more than usual.
You might also notice your cat drinking more water and urinating more frequently. Other symptoms include restlessness, hyperactivity, a rapid heartbeat, and vomiting.
Your cat’s fur might also start to look unkempt or matted, as they might stop grooming themselves as much.
More Serious Symptoms
If hyperthyroidism is left untreated, it can lead to more serious health issues, such as high blood pressure (hypertension), heart disease, and kidney damage.
Some cats may develop a condition known as thyrotoxic cardiomyopathy, where the heart muscle thickens due to the increased workload.
This can lead to heart failure if not managed promptly. Additionally, severe weight loss and muscle wasting can occur, significantly impacting your cat’s quality of life.
How is Hyperthyroidism Diagnosed?
What to Expect at the Vet
When you bring your cat to the vet with suspected hyperthyroidism, the vet will start by discussing your cat’s symptoms and medical history. A physical examination will be conducted, where the vet may feel for an enlarged thyroid gland in your cat’s neck. This enlargement is often detectable in cats with hyperthyroidism.
Blood Tests
The primary method for diagnosing hyperthyroidism is through blood tests that measure the levels of thyroid hormones in your cat’s blood, particularly the hormone T4 (thyroxine). Cats with hyperthyroidism usually have elevated levels of T4. In some cases, additional tests, such as free T4 (a more sensitive test) or imaging tests like ultrasound, might be recommended to assess the thyroid glands more closely.
Treatment Options for Hyperthyroidism in Cats
Medication
One of the most common treatments for hyperthyroidism is medication that helps reduce the amount of thyroid hormone produced by the glands. This medication, usually given daily, can effectively manage the condition, but it doesn’t cure the underlying problem.
It’s important for your cat to take the medication regularly, and regular vet visits will be needed to monitor thyroid hormone levels and adjust the dosage if necessary.
Radioactive Iodine Therapy
Radioactive iodine therapy is considered a definitive treatment for hyperthyroidism. It involves a one-time injection of radioactive iodine, which targets and destroys the overactive thyroid tissue while sparing the normal tissue. Most cats tolerate this treatment well, and it often results in a cure. However, it requires a stay at a specialised facility, as your cat will be radioactive for a short period afterward.
Surgery
Surgical removal of the affected thyroid gland(s) is another option, particularly if only one gland is involved. This surgery, called a thyroidectomy, can be curative, but it carries some risks, especially in older cats or those with concurrent health issues. Post-surgery, your cat will need monitoring to ensure the remaining thyroid tissue functions properly.
Dietary Management
In some cases, a special diet that is low in iodine can help manage hyperthyroidism. By reducing the amount of iodine in the diet, the thyroid gland’s ability to produce excessive hormones can be limited. This option may be recommended for cats that cannot tolerate medication or as an adjunct to other treatments.
What to Expect Long-Term
With proper treatment, the prognosis for cats with hyperthyroidism is generally good. Cats that undergo radioactive iodine therapy or surgery may be cured and live a normal lifespan. Those on medication can also live well, provided they receive regular monitoring and adjustments to their treatment. Early diagnosis and consistent management are key to maintaining your cat’s quality of life.
Caring for Your Cat
Ongoing care for a cat with hyperthyroidism includes regular vet visits to monitor thyroid hormone levels and adjust treatment as needed. If your cat is on medication, you’ll need to be diligent about giving it daily. A balanced diet that supports overall health is also important. If your cat has had surgery or radioactive iodine therapy, follow-up care will be necessary to ensure they recover fully and do not develop other thyroid issues.
Frequently Asked Questions (FAQs)
Can hyperthyroidism in cats be cured?
Yes, hyperthyroidism can often be cured, especially with treatments like radioactive iodine therapy or surgery. Medication and dietary management, while effective, manage the condition rather than cure it.
What happens if hyperthyroidism is untreated?
If left untreated, hyperthyroidism can lead to serious health problems such as heart disease, high blood pressure, and severe weight loss. It can also cause significant discomfort and reduce your cat’s quality of life.
Is there a special diet for cats with hyperthyroidism?
Yes, a low-iodine diet can help manage hyperthyroidism by reducing the thyroid gland’s ability to produce excess hormones. Your vet can recommend a suitable diet if this approach is appropriate for your cat.
How quickly will my cat improve after starting treatment?
Most cats start to show improvements within a few weeks of beginning treatment. Symptoms like hyperactivity and increased appetite typically subside first, followed by stabilisation of weight and heart rate.
Is hyperthyroidism common in older cats?
Yes, hyperthyroidism is quite common in older cats, particularly those over the age of ten. Regular vet check-ups are important for early detection and treatment.
Want to provide the best care for your senior pet? Subscribe to our Grey Muzzle Lovers newsletter and get the latest news and tips straight to your inbox. Subscribe today.
Comments