Hyperthyroidism in Cats: What Every Cat Owner Needs to Know

Thyroid diseases can happen in cats just as it happens in people. Having a middle-aged to senior kitty may mean keeping a closer lookout for Hyperthyroidism. Keep reading to find out what you need to know about hyperthyroidism in cats.

What is Hyperthyroidism?

If we break the word down, “hyper” means high and if we pair it with the thyroid it means that the thyroid gland, which is located at the base of the neck, is overactive, or it is producing too much thyroid hormone. This hormone is responsible for controlling the metabolic rate of the body. In this case, increasing the metabolic rate in a cat. This disease in cats results from a typically benign tumor in the thyroid gland. According to VCA Hospitals, fewer than 2% of hyperthyroid cases in cats involve malignant thyroid gland tumors. Hyperthyroidism in cats is a treatable condition and usually not a death sentence. 

A feline with hyperthyroidism

Who is at risk and what signs do I need to watch for?

Hyperthyroidism is more common in middle-aged to senior cats, and most cases are seen at 10 years of age and older.

Most cats that test positive for hyperthyroidism generally have lost weight quickly and no matter how much the cat eats, they just can’t gain any weight. Keep an eye on your cat’s weight and if they just seem too skinny, call your veterinarian. Personality changes are also common in new hyperthyroid cats, they may seem grumpy or even become aggressive. The fur of these cats also takes on an unkempt appearance. Increased water intake, excessive urination, vomiting, and diarrhea are also common. And don’t be surprised if your usually calm cat becomes hyperactive or experiences changes in their normal good kitty behavior.

hyperthyroidism in cats

What do I do if I think my cat is hyperthyroid?

The first step with any medical problem is to call your veterinarian. Discuss what is going on at home, any changes in diet or appetite, and any behavioral or environmental changes. Your veterinarian will want to conduct some blood tests to see what the thyroid levels are. They may also want to check the urine to ensure the kidneys are working properly. Depending on the severity, your veterinarian may also want to check your cat’s blood pressure and possibly perform an ultrasound on the heart.

Above all, it’s very important to have your cat examined and to develop a plan to treat should they be diagnosed with hyperthyroidism. Dr. Kathryn Primm, owner and operator of Applebrook Animal Hospital in Chattanooga, TN says, “Untreated hyperthyroidism causes damage to the heart and these cats are at high of sudden cardiac death.”

Please do not send your cat into an early grave by forgoing treatment. It could mean the difference between life and death for your feline friend. 

How is hyperthyroidism treated?

Hyperthyroidism cannot be cured, however, it can be treated and maintained. After diagnosis, your veterinarian will want to prescribe medication for your cat. For the treatment to work, you need to be able to medicate your cat as prescribed. After a month or so, your veterinarian will most likely want to retest your cat’s bloodwork for thyroid levels to see if any dosing adjustments need to be made. Thyroid disease in cats is not a rare ordeal, so there are many different routes for medication administration, such as pills, liquid, and a handy cream that can be administered topically to the inside of a cat’s ear. Specific food may also be recommended by your veterinarian.

Radioiodine Therapy, also referred to as Radioactive Iodine Treatment, is another method used for treating hyperthyroidism in cats.

PetMD.com shares that most cats that undergo the I-131 treatment are cured of the disease with a single treatment. The radioactive iodine is used to specifically target and kill off the diseased tissue located in the thyroid gland. However, this treatment is costly and not an ideal option for every cat owner.

Image Courtesy of Cornell University

The best way to stay informed about your cat’s health is to keep up with their appointments with a veterinarian. Once your cat reaches the age of seven, ask for routine senior bloodwork to establish a baseline to include the kidney and thyroid levels, this way if there are any changes, you and your veterinarian have a reference point. Be attentive to changes and listen if your kitty tries to tell you something is happening with their body! After all, you know them best!

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