Canine Hypothyroidism

Reprinted From

What Is Hypothyroidism?

All mammals have a thyroid gland. It is located in the neck and constantly produces thyroid
hormone which speeds up metabolism. Hypothyroidism occurs when the gland stops
functioning and producing thyroid hormone. It is one of the most common hormonal diseases.

What causes Hypothyroidism?

"Hypothyroidism usually happens for unknown reasons," says Dr. Leslie Henshaw, a
> dermatology resident and veterinarian at the University of Illinois College of Veterinary
> Medicine Teaching Hospital at Urbana. "Most of the other cases are caused by a
destruction of the thyroid gland by the immune system."

What Dogs Are Most Likely To Be Affected?

This disease usually affects middle-aged dogs and while it is seen frequently in Golden
Retrievers, Irish Setters, and Dobermans, it can manifest in any breed.

What Are Some Of The Symptoms?

"The first symptom that is usually seen is hair loss," remarks Dr. Henshaw. "It is usually not
associated with other skin problems." Other symptoms may include weight gain, muscle
loss, lethargy, and a tendency to seek heat (especially in winter). Pet owners usually
attribute many of these symptoms to the pet's aging process.

Is This Disease Life -Treatening?

"This is not a life-threatening disease," says Dr. Henshaw. "If it is left untreated however, the
lethargy will get worse, the dog may experience a mental dullness, and the heart rate can be slow."
"The symptoms with hypothyroidism are usually subtle at first," she observes. "It is a gradual
process which takes months to one year to develop."

How Can I Find Out If My Dog Has Hypothyroidism?

Diagnosis of this disease is done by a series of blood tests. These tests are fairly common
> and can be conducted by your veterinarian.

Is There A Cure For This Disease?

While hypothyroidism is not a curable disease, notes Dr. Henshaw, it is very treatable. "The
> treatment consists of oral supplementation of the thyroid hormone on a daily basis. It is very
> safe, life-long, and relatively inexpensive. Treatment often rejuvenates a dog." Many dog
owners are familiar with hypothyroidism because it is a disease which also occurs in people.
Although there are many similarities, owners of hypothyroid dogs should follow the advice
of their veterinarian, as the dosage of thyroid hormone supplementation is very different for
dogs..

Complications?

Dr. Henshaw remarked that hypothyroidism can complicate other skin diseases and, if left
untreated, will affect the quality of life. Once diagnosed, there are virtually no side effects
from the drug therapy and there is very little monitoring needed. Once the hypothyroidism is
controlled with drug therapy, a dog will no longer be predisposed to other disease
conditions. Dog owners are often pleasantly surprised that their "old dog" is acting
"younger."

For Further Information:
If you would like further information or would like to have your dog tested for
hypothyroidism, contact your local veterinarian.

Common Symptoms of hypothyroidism

Lethargic behavior such as a lack of interest in play, frequent napping, tiring out on long walks
Weight gain, sometimes without an apparent gain in appetite
Bacterial infections of the skin
Dry skin
Hair loss, especially on the trunk or tail (“rat’s tail”)
Discoloration (darkening) or thickening of the skin where hair loss has occurred
Cold intolerance/seeking out warm places to lie down
Slow heart rate
Chronic ear infections
Severe behavioral changes such as unprovoked aggression, head tilt, seizures, anxiety and/or compulsivity
Depression
> Reproductive difficulty (although it does not always affect reproductive success) It is, however, also important to remember that hypothyroidism is considered to be a heritable condition, which should be factored into breeding decisions.