Canine Hypothyroidism, a Dog Owner’s Guide to Cause, Symptoms and Treatment

As in humans, hypothyroidism is a disorder of the thyroid gland with a most distinct symptom of weight gain. So true, also, with man’s best friend. In your dog, hypothyroidism exhibits the same, if not worse, symptoms but can be treated resulting in a normal and healthy lifespan. The thyroid gland in both dogs and humans provides the same hormonal and metabolic balance and function. Understanding the causes of canine hypothyroidism, symptoms and treatment options, will guide you into the proper method for diagnosing and treatment options which leads to a full and productive life.

The canine thyroid gland is similar to that found in humans. As a dual butterfly shaped lobe located in the neck, the thyroid gland serves the same hormonal and metabolic function in dogs as is found in humans. Statistics have shown that almost 90% of new canine hypothyroidism cases develop from a decrease in the canine’s immune system resulting in an attack of the healthy thyroid tissue. As in humans, the condition is often genetic but can be brought on by pollution and allergens with larger dog breeds suffering more often than smaller breeds and spayed females more often afflicted than any other type of dog. Additionally, pure breed dogs tend to be more often afflicted than mixed breed types.

If struck with hypothyroidism, your dog will show a variety of symptoms which could easily be mistaken for other conditions such as heat exhaustion, parvo or influenza. Symptoms range from lethargy, paralysis, drooping eyelids, some weight gain, hair loss, slowed heart rate to even ear infections. You may also begin to notice what appears to be signs of depression and notice some seizure activity in your dog. Constipation, diarrhea and vomiting have also been seen as common symptoms of the disorder.

If you believe your dog may be suffering from hypothyroidism, your veterinarian will conduct a series of thyroid hormone tests which are similar to those conducted on humans. If positively diagnosed, your dog may be required to take a daily dose of a synthetic thyroid hormone which usually begins with a double dose for the first six to eight weeks and then tapers to one dose per day. Because the thyroid medications “half life” occurs over a 12 hour period, double dosing may extend beyond the initial eight week period. In rare cases, removal of the thyroid gland may be required. Following an examination and positive diagnosis, your physician will discuss the best treatment options available.

For pure breed female dogs, the dog owner will need to carefully consider the surgical treatment options versus the medication hormone replacement therapy. Because the synthetic thyroid medication may result in birth defects, for dog breeders, the option for surgical removal of the thyroid gland versus continued partial medication therapy should be strongly considered. Once the thyroid gland is removed, your dog will be on medication for the remainder of her lifespan. Whereas, deferring surgery may provide the thyroid gland an opportunity to regain function with a partial medication period. Thus, pure dog breeding can proceed at a safer level.

So, when interacting with your dog on a daily basis, watch for signs in behavior. When the onset of symptoms begin, encourage your veterinarian to begin extensive blood work to rule out a thyroid disorder. If postively diagnosed, early treatment may lead to full recovery and, even if not fully recovered, will provide your dog with a full and productive lifespan.