In late October Chamonix was diagnosed as hypothyroid, a condition in dogs where where the thyroid gland is not secreting normal amounts of thyroid hormone, is the most common endocrine gland disorder in the dog.

She presented with symptoms of lethargy, vomiting and poor appetite. Her Doc ran a blood panel and noticing that her cholesterol was elevated also ran tests for thyroid function. Her tests indicated she was producing antibodies at an extremely elevated rate that were, in effect, attacking and killing her thyroid cells.

Fortunately we were able to catch this condition early and she had not suffered loss of her coat or any skin complications. She is now on thyroxine and will be retested regularly for medication effectiveness.

So...what is hypothyroidisim and what are the symptoms.....

Hypothyroidism results from the impaired production and secretion of thyroid hormone. The production of thyroid hormone is influenced by the pituitary gland, the hypothalamus and the thyroid gland. Although dysfunction anywhere in the complicated hypothalamic-pituitary-thyroid pathway can result in hypothyroidism more than 95% of all cases occur as a result of destruction of the thyroid gland. About half of the causes of thyroid gland destruction are suspected to be caused by the dog's own immune system killing the cells of the thyroid gland. The other half is caused by atrophy of the thyroid tissue and resultant infiltration of the tissue by fat. The cause for this form of the disease is unknown.

Thyroid hormone is needed for normal cellular metabolic function. A deficiency of thyroid hormone affects the metabolic function of all organ systems. As a result the symptoms are usually variable and non-specific. There is not a specific symptom that is diagnostic for hypothyroidism. There are however several symptoms that when combined together make the veterinarian more suspicious of the likelihood of the animal having the disease. A study on hypothyroid dogs revealed the following information on the variety and frequency of symptoms seen with the disease: lethargy, coat loss, weight gain (or obesity) and dry coat. Other symptoms might include; hyperpigmentation of skin, cold intolerance, slowed heart rate high blood cholesterol and/or anemia.

One of the good things about this disease is that it is easily treated. Treatment consists of putting the dog on a daily dose of synthetic thyroid hormone called thyroxine (levothyroxine). There are numerous brand names of this drug. The dose and frequency of administration of this drug varies depending on the severity of the disease and the individual response of the animal to the drug. A dog is usually placed on a standard dose for his weight and then blood samples are drawn periodically to check his response and then the dose is adjusted accordingly. Once therapy is started the dog will need to be on treatment for the rest of its life. Usually after the treatment is started the majority of the symptoms resolve.