*Q* What is the difference between hyperthyroidism, hypothyroidism and Hashimoto's Disease? How long would it take someone with Hashimoto's who is not getting treated for it to experience problems, and what kind of problems would she encounter?
*A* Hyperthyroidism results from overproduction of thyroid hormone, while hypothyroidism is inadequate formation of thyroid hormone. Hashimoto's is a specific disease of the thyroid gland that is one of the most common causes of hypothyroidism.
People with Hashimoto's have chronic inflammation of the thyroid gland (thyroiditis). Although its cause is unknown, it is thought to be due to an abnormality of the immune system that leads to the development of antibodies against thyroid cells. The earliest sign of Hashimoto's is a painless enlargement of the thyroid gland (goiter).
Most individuals still have normal thyroid function when Hashimoto's is first diagnosed on the basis of the thyroid enlargement. But continued antibody attack eventually can destroy the thyroid gland and cause hypothyroidism.
The time between detection of an enlarged thyroid and the onset of hypothyroidism is unpredictable.
Hashimoto's is more common in women than men, and there is often a history of other family members with Hashimoto's or other thyroid diseases.
No treatment is available to stop the production of antibodies or prevent the destruction of the thyroid. The goals of treatment with thyroid hormone are to shrink the size of the oversized thyroid gland and to prevent or treat the symptoms of hypothyroidism. Hormone treatment is lifelong.
When Hashimoto's is not treated, results can be striking. They include fatigue, lethargy, slow speech, hoarseness, sensitivity to cold, cold skin that is dry and coarse, hair loss, constipation, impaired memory, swelling of the eyelids, ankle swelling and excessive menstrual bleeding.
The earliest symptoms of hypothyroidism often are subtle and the cause may not be recognized. Once suspected, the diagnosis is readily made by measuring blood levels of thyroid hormone and thyroid stimulating hormone (TSH).
*Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for academic affairs at the school.