How To Spot Hyperthyroidism In Your Cat

3 min read

Cats are masters at hiding illness, which makes early detection of health problems a real challenge for pet owners. One condition that’s especially sneaky—but common in older cats—is hyperthyroidism. Left untreated, it can lead to serious heart, kidney, and weight-loss issues. The good news? If you know what to look for, you can catch the signs early and work with your veterinarian to manage it effectively.

In this post, we’ll cover what hyperthyroidism is, the key signs to watch for, how your vet will confirm the diagnosis, and why early detection can make all the difference in your cat’s long-term health.

What Is Hyperthyroidism in Cats?

Hyperthyroidism occurs when the thyroid glands (located in your cat’s neck) produce too much thyroid hormone. This speeds up your cat’s metabolism, causing their body to essentially “run in overdrive.”

It’s most common in cats over 10 years old and can be caused by benign growths on the thyroid gland. While the condition is treatable, catching it early is critical to preventing irreversible organ damage.

Common Signs of Hyperthyroidism in Cats

While every cat is different, here are some of the most frequent symptoms owners notice:

• Weight loss despite a healthy (or even increased) appetite

• Increased thirst and urination

• Restlessness or hyperactivity

• Unkempt or matted coat

• Vomiting or diarrhea

• Rapid heartbeat or labored breathing

🔍 Tip: Many owners mistake early hyperthyroidism for “normal aging.” If your older cat seems to have more energy but is losing weight, it’s worth a vet check.

How Your Vet Will Diagnose Hyperthyroidism

Diagnosis usually involves a physical exam (the vet may feel an enlarged thyroid gland) and a simple blood test to measure thyroid hormone (T4) levels.

💡 Good to know: Because hyperthyroidism can mask kidney disease, your vet may also recommend additional lab work to check kidney function.

Why Early Detection Matters

Catching hyperthyroidism early can:

• Prevent heart damage from prolonged overactive metabolism

• Preserve kidney health

• Make treatment more effective and less costly

• Help your cat maintain a healthy weight and quality of life

  
  

Treatment Options

Once diagnosed, your veterinarian may recommend one or more of the following:

1. Medication – Daily oral tablets or transdermal gel to control hormone production

2. Special Diet – Iodine-restricted food to limit thyroid hormone production

3. Radioactive Iodine Therapy – A one-time treatment that can cure the condition

4. Surgery – Removal of the affected thyroid gland

📣 Your vet will help you decide which option is best based on your cat’s age, overall health, and lifestyle.

Key Takeaways

💵 Costs add up – Hyperthyroidism often requires lifelong treatment or monitoring, so budget accordingly.

🏪 Convenience matters – Some medications for hyperthyroidism, like methimazole, can be filled at human pharmacies—often at a lower price with a prescription discount card.

📱 Stay proactive – Regular vet visits for senior cats are the best way to catch this and other age-related conditions early.