Hyperthyroidism Treatment for Cats in Monona and Madison
If your senior cat is eating more than ever but still losing weight, hyperthyroidism may be the reason. It is the most common hormonal disorder in older cats and is highly treatable when caught early. As a Cat Friendly and Fear Free practice, Four Lakes Veterinary Clinic offers gentle diagnosis and long-term care for hyperthyroid cats.
What Is Hyperthyroidism?
Hyperthyroidism occurs when the thyroid glands in the neck produce too much thyroid hormone, usually because of a benign growth called an adenoma. Thyroid hormone controls metabolism, so excess hormone causes the body to burn energy too quickly. Over time, this puts strain on the heart, raises blood pressure, and can mask or worsen kidney disease. Most affected cats are 10 years or older. The condition is rare in dogs.
Signs of Hyperthyroidism in Cats
- Weight loss despite a big appetite
- Increased thirst and urination
- Restlessness, hyperactivity, or nighttime yowling
- Vomiting or diarrhea
- A rapid heart rate or heart murmur
- An unkempt, greasy, or matted coat
Many of these signs overlap with diabetes and kidney disease, which is why bloodwork is so important for senior cats. If your cat shows these changes, schedule a sick pet visit.
How We Diagnose Hyperthyroidism
Your veterinarian will check your cat’s weight, heart, blood pressure, and neck for an enlarged thyroid gland. A blood test measuring total T4, the main thyroid hormone, confirms most cases and is processed through our in-house laboratory testing. A complete senior panel and urinalysis help us evaluate kidney function at the same time, since treating hyperthyroidism can reveal underlying kidney disease. Some cats also benefit from heart imaging through an ultrasound or specialist referral.
Treatment Options for Hyperthyroid Cats
There are several effective treatments, and we will help you choose the best fit for your cat and family:
- Daily medication: methimazole, given as a pill or a transdermal gel applied to the ear, controls thyroid hormone levels. It is available from our pharmacy.
- Prescription iodine-restricted diet: a food that limits the iodine the thyroid needs to make hormone. It must be the only food your cat eats and can be shipped through our online store.
- Radioactive iodine therapy: a one-time treatment that cures most cats, offered at specialty referral centers.
- Surgery: removal of the affected thyroid gland, which is less common today but appropriate for some cats.
Cats on medication or diet therapy need regular rechecks to monitor thyroid levels, kidney values, and blood pressure.
Senior Cat Screening Matters
We recommend wellness exams every six months and routine bloodwork for cats over age 10, since early detection makes treatment easier and protects the heart and kidneys. Keep up with vaccines and dental care during these wellness exams, and if your cat needs a place to stay while you travel, our cat boarding team can continue daily medications. Learn about other conditions we treat on our conditions page.
Hyperthyroidism in Cats FAQs
What causes hyperthyroidism in cats?
Most cases are caused by a benign, non-cancerous growth on one or both thyroid glands that produces too much thyroid hormone.
How is hyperthyroidism diagnosed?
It is usually diagnosed with a blood test that measures T4 thyroid hormone, along with a physical exam and senior bloodwork to check other organs.
Can hyperthyroidism in cats be cured?
Radioactive iodine therapy and surgery can cure most cats. Medication and prescription diets control the condition but do not cure it.
Is methimazole safe for cats?
Methimazole is safe and effective for most cats. Regular bloodwork helps monitor for rare side effects and makes sure the dose is right.
Can I give my cat thyroid medication without pills?
Yes. Methimazole is available as a transdermal gel that is rubbed onto the inside of the ear, which many cats tolerate more easily than pills.
What happens if hyperthyroidism is not treated?
Untreated hyperthyroidism can lead to severe weight loss, heart disease, high blood pressure, and blindness from retinal damage.
Can my hyperthyroid cat board with you?
Yes. Our cat boarding team can give medications and monitor your cat closely while you are away.
Help Your Senior Cat Feel Like Themselves Again
Unexplained weight loss in an older cat should always be checked. Call Four Lakes Veterinary Clinic at (608) 819-6750 to schedule a senior cat exam in Monona and Madison.