Hashimoto thyroiditis is a chronic inflammation of the thyroid gland. The thyroid gland is in the front of the neck just below the Adam's apple. It secretes thyroid hormone, which is important in metabolism throughout the body.
Hashimoto thyroiditis is considered an autoimmune disease. This means that a person's immune system attacks his or her own body. No one knows why this happens. With this disease, the immune system attacks the thyroid gland. This can cause thyroid hormone imbalances. Hashimoto thyroiditis is one of the most common causes of a low thyroid hormone level, called hypothyroidism.
The exact cause of Hashimoto thyroiditis is not known. As with all autoimmune disorders, the immune system abnormally attacks the body. Hashimoto thyroiditis also occurs more often in people who have other autoimmune disorders and diabetes.
Symptoms of Hashimoto thyroiditis may include:
Most people who have Hashimoto thyroiditis will have a low level of thyroid hormone. So, these symptoms are primarily related to this low level. Symptoms from low thyroid hormone are usually what cause a person to see the doctor.
In other cases, the thyroid hormone level may be high, which causes almost opposite symptoms. For example:
The doctor will take a medical history and complete a physical examination. He or she will usually order blood tests, including:
Additional blood tests or special X-ray tests can usually confirm the diagnosis of Hashimoto thyroiditis.
Sometimes a thyroid fine needle biopsy may be needed. To do a biopsy, the doctor will take a small sample of the thyroid gland with a special needle that he or she inserts through the skin. The doctor can look at this sample under a microscope to make the diagnosis.
Nothing can be done to prevent the disease because the exact cause is not understood.
Hashimoto thyroiditis often causes low thyroid hormone levels, called hypothyroidism. This condition may be permanent. This means that the person may need to take thyroid hormone replacement medicine for the rest of his or her life.
There are no risks to others, as this disease is not contagious.
Treatment generally focuses on managing the level of thyroid hormone. If the level is low, as it is in most cases, the doctor will prescribe thyroid hormone pills. If the thyroid level is high, the doctor will prescribe medicines that block thyroid hormone from working in the body. Rarely, surgery may be needed if the thyroid gland gets too big.
All medicines have side effects. If too much thyroid medicine is given, the levels can become toxic. Medicines used to treat abnormal thyroid levels may cause:
Surgery carries the following risks:
A person with Hashimoto thyroiditis often requires monitoring and treatment for life.
Periodic thyroid function tests and visits to the doctor are recommended to monitor the course of the disease. Any new or worsening symptoms should be reported to the doctor as well.
Author:Adam Brochert, MD
Date Written:
Editor:Crist, Gayle P., MS, BA
Edit Date:02/08/02
Reviewer:William M. Boggs, MD
Date Reviewed:01/31/02
Cecil's Textbook of Medicine, 1996, Bennett et al.