Hypothyroidism in dogs is, as the title says, a result of thyroid problems in dogs, namely an underactive thyroid gland. This can be due to a decrease in production of the hormones or secretion of the hormones. Canine hypothyroidism is the most common endocrine problem in dogs.
The Thyroid
The endocrine system is made up glands that produce hormones. The whole system is comprised of complex interactions. One such system is called the hypothalamic-pituitary-adrenal axis. This axis is very important for thyroid function because the hormones produces by the hypothalamus controls the thyroid.
The thyroid gland performs very important functions in the body. It produces many hormones, the two most important are called called triiodothyronine and thyroxine. It’s easier to call them by their shortened names, T3 and T4. These hormones act all over the body, including in cardiac function and metabolism.
Hypothyroidism in Dogs
There are two types of hypothyroidism in dogs: primary and secondary. The most common for is primary canine hypothyroidism, which means that the thyroid is destroyed by something. Most often this is caused by a tumor. The second most common cause is an immune mediated disease that attacks the thyroid. Secondary hypothyroidism is caused by a decrease in the hormone that is responsible for thyroid control. This is discussed above in The Thyroid section.
Signs and Symptoms Canine Hypothyroidism
Since thyroid hormones effects various systems, there is practically an infinite number of possible symptoms, many of which will be undetectable without tests.
The dog will be lethargic, gain weight, show a reluctance to exercise, always feel cold and have skin problems such as dry coat, seborrhea, alopecia and dark coloration. These are all due to a decreased metabolism.
Diagnosis of Hypothyroidism
Because canine hypothyroidism can mimic many, many other diseases, diagnosis is basically based on tests. These tests include a thyroid function test or levels of the thyroid hormones. There are actually a number of tests that your local veterinarian or animal hospital can perform. If you would like to know more details, ask your vet. There are also sites that offer online vet advice where you can find more information out about these tests.
Treatment of Hypothyroidism
The treatment of this disease involves administering synthetic hormones, namely L-thyroxine. Usually a dog is given a certain dosage twice a day until improvement is seen and then the dosage is usually lowered. The dog will probably need to be treated for the rest of his or her life. You will need to involve your local veterinarian as well because the dog will probably need testing to make sure that the dosage is correct. Most often dogs will return to normal after treatment for hypothyroid.
Final Thoughts
Hypothyroidism in dogs is a disease that affects the entire furry body but in subtle and discrete ways that mimic many diseases. If you want to learn more about this disease, there is a book called The Canine Thyroid Epidemic: Answers You Need for Your Dog.
