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How Will My Veterinarian Check My Cat for Hyperthyroidism?

Reviewed by Dr. Peter Kintzer, DVM, DACVIM on Monday, August 3, 2015
Posted August 27, 2014 in Cat Diseases & Conditions A-Z

Cat getting a checkup at the vet

Hyperthyroidism, like many diseases of cats can be somewhat unclear in onset. Clinical signs, according to Washington State University, can sometimes be clear and other times are very hard to evaluate.

[Editor’s Note: Click here for a basic explanation of hyperthyroidism or continue reading to learn how your veterinarian may test for it.]

Is my cat hiding hyperthyroidism?
Sometimes, symptoms of hyperthyroidism will be so subtle they will be missed entirely. In those cases, the disease is often caught because a cat is considered to be at risk due to age. As a result, tests are run to prove or disprove an abnormal thyroid level. A diagnosis of hyperthyroidism is made when the level of thyroid hormone is increased in the blood. Most hyperthyroid cats have very high levels of hormone but some cats will have signs of hyperthyroidism with normal or only slightly increased levels of thyroid hormone1.

How will my veterinarian check my cat’s thyroid?
Your veterinarian will start with a thorough, physical examination and will probably weigh your cat--most cats will lose significant amounts of weight. Your veterinarian will listen carefully for abnormal heart rate and rhythm. Cats with hyperthyroidism, typically, have a rapid heart rate and many will have an abnormal heart rhythm. 

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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.