As our dogs age, it is common for them to put on some weight. In most cases, the cause is simply over feeding, too many treats, or a lack of proper exercise. In some cases, however, unexpected weight gain, along with other symptoms, may be due to a low production of thyroid hormone, a condition known as hypothyroidism. Hypothyroidism, though rare in cats, is the most common hormone abnormality we diagnose in dogs.

Thyroid hormone is produced by the two-lobed thyroid gland located on the underside of a dog’s neck near the larynx. This hormone helps regulate vital body functions such as heart rate, breathing, the nervous system, body weight, muscle strength, temperature and cholesterol levels. Symptoms associated with hypothyroidism include weight gain, lethargy, mental dullness, exercise intolerance, and hair loss. The typical hypothyroid dog is 2 and 9 years old when the symptoms first develop and males and females are equally affected. Hypothyroidism is more common in certain breeds such as Golden Retrievers, Doberman Pinschers, Great Danes, Irish Setters, Miniature Schnauzers, Dachshunds and Boxers.

If your middle age or older dog is showing any of the typical signs of hypothyroidism, we can run tests here at Beaverton Pet Clinic to measure thyroid and cholesterol levels. In some cases, confirming tests sent to our reference lab may be necessary to ensure a proper diagnosis. Treating hypothyroidism is simply a matter of giving a synthetic thyroid hormone tablet (L-Thyroxine) twice daily and doing periodic follow up blood work.

– Dr. Chris Wilson