Escondido, CA
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What do I need to know about Thyroid disease?

Ask the Vet

Thyroid disease is a very common problem in the older cat and dog. As a cat ages, their thyroid gland tends to develop a functional tumor that causes it to produce extra thyroid hormone (hyperthyroidism). Meanwhile, a dog’s thyroid gland tends to slow production as he or she ages (hypothyroidism). As a result of these differences, cats and dogs have very different physical and physiological responses.

The thyroid gland is key to the metabolic functioning of the animal’s body. It regulates the body’s ability to break down food and convert it to energy. In cats, hyperthyroidism most commonly manifests as complaints that the cat is eating like a horse and still losing weight. The cat’s coat is frequently dry and unkempt. If unmanaged, the cat’s health will deteriorate and multiple organs can be affected. Hypothyroidism, in dogs, is frequently seen as the dog slowing down and getting fatter even though the quantity of food hasn’t changed. The coat is similarly dry and unkempt. If untreated, hypothyroidism can also affect multiple body systems of the dog.

Diagnosis is usually quite simple. It usually takes a quick blood test to determine the thyroid levels. Treatment of hypothyroidism, in dogs, is as easy as supplementing thyroid hormone. Treatment of hyperthyroidism in cats has more options. The most common treatment course is administering a medication to suppress the excessive thyroid production. Another excellent treatment is to have the thyroid gland treated so that the tumor cells in the thyroid are killed, thereby decreasing the thyroid levels. A third option is to feed a special diet that has a severely restricted iodine content. All of these, with the exception of killing the tumor cells, require life long treatment.

Both conditions are very manageable but require periodic monitoring to make sure the levels are correct.  Both conditions can be diagnosed fairly early in the disease process to prevent the pet from physically declining. I talk about lab work a lot, but that’s only because it’s really important.

Let your vet help you! It’s what we do.


“Ask the Vet” is a monthly feature of the Times-Advocate brought to you by Dr. David Knox of Companion Animal Clinic. If you have a question for the Vet, please submit it to:

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