Famished felines: Recognising and managing cat hyperthyroidism

If your cat is eating ravenously yet losing weight, it may have hyperthyroidism, a common condition in middle-aged to older cats. This guide explains its causes, symptoms, diagnosis, and modern treatments available in the UK to help your feline live comfortably and healthily.

What is the thyroid gland and why does it matter?

The thyroid gland is a small, double-lobed organ located in your cat's neck that regulates metabolism by producing thyroid hormones. These hormones control how quickly your cat’s body uses energy, influencing everything from activity levels to bodily functions. Iodine from their diet is essential for producing these hormones.

What causes hyperthyroidism in cats?

Hyperthyroidism usually arises from a benign enlargement called an adenoma on the thyroid gland, causing excess thyroid hormone production. While the exact cause is unknown, risk factors include indoor living and feeding primarily canned food. Both male and female cats are equally affected. Siamese cats seem less prone to this disease. Rarely, a malignant tumour called thyroid adenocarcinoma causes the problem, requiring specialist veterinary care.

How does hyperthyroidism affect your cat?

The enlarged thyroid gland produces too much hormone, speeding up metabolism. This means your cat feels hungrier and more active but simultaneously burns fat faster, leading to weight loss despite eating more. High blood pressure and heart complications may also develop if untreated, possibly causing blindness or heart failure over time.

Recognising symptoms early

• Increased appetite: Your cat seems insatiable, begging for food frequently.
• Weight loss: Despite eating more, your cat becomes thin.
• Increased thirst and urination: Drinking and peeing more than usual.
• Digestive issues: Occasional vomiting or diarrhoea.
• Poor coat condition: Dull or greasy fur indicating health changes.
• Behavioural changes: Restlessness, irritability, or heat intolerance.
• In some cases: Panting or excessive vocalisation may be seen.

Note that these signs can also appear in other illnesses like diabetes or kidney disease, so professional veterinary assessment is important.

Diagnosing hyperthyroidism

Suspecting hyperthyroidism means timely vet consultation for a thorough check-up. Diagnosis mainly relies on a blood test measuring thyroid hormone levels, supported by urine and blood tests assessing kidney and other organ health. Since hyperthyroidism can mask kidney disease, rechecking after treatment starts is common. Heart function may also be assessed if abnormalities appear, using ultrasound or ECG, along with blood pressure monitoring.

Sometimes the test may give false negatives, especially in early stages or concurrent illness, so repeating tests or alternative methods could be necessary.

Treatment options available in the UK

Four main treatments exist, each with pros, cons, and considerations for your cat’s lifestyle and health:

1. Medication (Tablets)

Thyroid hormone synthesis blockers normalise hormone levels, relieving clinical signs. Most cats take medication once or twice daily indefinitely, with regular vet visits and blood checks to monitor response and side effects. Stopping medication risks relapse.

2. Surgery (Thyroidectomy)

Removal of the thyroid gland, partially or totally, can permanently cure the condition. Due to anaesthetic risks in hyperthyroid cats, stabilising medication before surgery is advised. Recurrence is possible if ectopic thyroid tissue exists elsewhere.

3. Radioactive iodine therapy

Administered at specialist UK centres, this destroys overactive thyroid tissue selectively. Cats require several weeks hospitalisation for safety but treatment boasts a 95% cure rate with a single injection.

4. Prescription diet (Hill's y/d)

A low-iodine diet that normalises hormone levels within weeks. Strict dietary compliance is essential to avoid iodine intake from other foods. Your cat will stay on this diet lifelong as a non-invasive treatment option.

Supporting your cat’s health

Managing hyperthyroidism involves not just treating the thyroid but monitoring and supporting other organs, especially the kidneys and heart. Regular vet check-ups and blood pressure monitoring help detect complications early. Responsible ownership includes adhering to prescribed treatments and communicating promptly with your vet about any changes.

When to see your vet

If your older cat shows increased appetite with weight loss, increased thirst, behavioural changes, or coat deterioration, make a veterinary appointment promptly. Early diagnosis and treatment improve quality of life and prognosis.

Responsible pet ownership and ethical considerations

When caring for cats with chronic conditions like hyperthyroidism, commitment to ongoing care and veterinary advice is essential. Avoid self-medicating or sudden treatment changes. Ensure any diet changes or medications come under professional guidance.

Remember, adopting cats from reputable sources and providing them a stable, varied diet can reduce health risks and promote a long life.

Conclusion

Hyperthyroidism is a common but manageable condition in older cats. Recognising key symptoms early, working with your vet for diagnosis, and considering available treatments can ensure your cat continues a happy, healthy life. Whether through medication, surgery, radioactive iodine, or diet, options exist to suit many cats and owners. Prompt veterinary care combined with responsible ownership provides the best outcome.

For cats showing signs of hyperthyroidism, visit your vet early to discuss diagnosis and management tailored to your feline’s needs.