Hypothyroidism

« Back to Glossary Index

Hypothyroidism is underactivity of the thyroid gland, a butterfly shaped gland in the neck. Inadequate amounts of thyroxine (the hormone produced by the thyroid gland) is called hypothyroidism which can sometimes be an auto-immune disorder. Thyroxine is hematopoeitic. i.e. it encourages the production of red blood cells & it is therefore very important in cases of anemia to check for hypothyroidism. Many vets recommend giving thyroxine in cases of AIHA/IMHA to stimulate red cell production (erythropoeisis), even if thyroxine levels are “normal”. AIHA/IMHA may damage the thyroid gland.

Thyroxine, the hormone produced by the thyroid gland, plays a large role in controlling the whole of the metabolism of the body, including food metabolism, resistance to infection, development & growth, oxygen utilization, also reproduction.Symptoms in dogs include chronic infection, especially of the skin & ears, lack of energy & extreme fatigue, exercise intolerance, dry flaky skin, weight gain despite eating the same amount, hair loss, slow heart rate & inability to tolerate the cold. Other important symptoms include depression, to the point of anxiety, aggressiveness, tilting of the head, compulsive behaviour & seizures (which can obviously be life-threatening).

Some breeds are genetically pre-disposed to hypothyroidism, such as Irish Setters, Airedale Terries, Greyhounds, Golden Labrador/Retrievers, Dobermans & Cocker Spaniels. Other causes are drugs (particularly corticosteroids), toxins, vaccines & lack of exercise. Hypothyroidism is uncommon in smaller dogs. Unlike humans, male & female dogs appear to acquire this disease at around the same rate, but spayed females are more susceptible to developing hypothyroidism than males & unspayed females.

Thyroid test – A blood test can be undertaken to see if your dog is hypothyroid. It is advisable to compare results with results of the same or similar breed of dog if possible, due to variation in breed profile.

Hypothyroidism can sometimes be a secondary disease (as symptom) to an adrenal gland problem (e.g. Cushings Disease) and tests should be done for adrenal gland function too. If adrenal gland therapy is necessary, the thyroid problem will often improve or even resolve itself completely.

« Back to Glossary Index