This post deals with Canine Hypothyroidism because except in a few very extreme circumstances Feline Hypothyroidism does not exist. The thyroid gland is a small gland in the neck adjacent to the windpipe. It is considered a master gland and is responsible for producing thyroid hormones which have an effect on many parts of the body, including the skin and hair coat, metabolism, behaviour, attitude and even bone marrow function. Hypothyroidism occurs when the gland does not produce enough thyroid hormone.This deficiency is can be caused by immune-mediated destruction of the thyroid gland, by natural atrophy of the gland, by dietary iodine deficiency, or as a congenital problem. In dogs, the first two causes listed account for almost all cases.
Hypothyroidism generally develops in middle aged or elderly dogs. Breeds with definite predisposition to develop hypothyroidism include: the Doberman pinscher, the Golden retriever and Labrador Retriever, the Irish Setter, the Great Dane, the Dachshund, the Boxer, and the Beagle. That said, it can develop in just about any breed including mixed breed dogs.
Clinical signs of Hypothyroidism include poor haircoat or loss of hair particularly along the sides, obesity, lethargy, anemia and elevated blood cholesterol. Thickened skin is also a classical sign of this disease. A slower than normal heart rate is also seen. Neurological signs such as weakness, aggression and muscle atrophy can be seen but are not common. Megaesophagus ( an enlarged esophagus) and laryngeal paralysis ( a cause of roaring in dogs) as well as infertility have also been linked with hypothyroidism.
Hypothyroidism is diagnosed with a blood test or a series of blood tests that measure T4 or T3 or Antibodies. The conventional treatment of this condition is replacement of the hormone with a synthetic hormone and this treatment usually works quite well. There is a natural canine thyroid glandular from Standard Process which may or may not be effective. There is also a natural thyroid supplement that is used for humans but it is considerably more expensive than the synthetic hormone. Chinese herbs and homeopathy can also help. Most of the thyroid supplements should have Kelp in some form, Astragalus and Eleutherococus Senticosus. These are contained in the herbal supplement Thyro-Up and it can help if the thyroid has not been totally destroyed. However if the thyroid has been totally destroyed, supplement with the hormone L-thyroxine has proved the most effective treatment. I always like to supplement these dogs’ diets with Seaweed as this is helpful.