Hashimoto's Thyroiditis

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Also known as: Chronic thyroiditis; autoimmune thyroiditis

What is it?
Hashimoto’s thyroiditis is an inflammation of the thyroid gland (thyroiditis) that frequently results in hypothyroidism, or decreased thyroid gland function. It is the most common form of thyroiditis and most frequent cause of hypothyroidism.

This disorder is caused by a reaction of the immune system against the thyroid gland. When the immune system targets part of the human body such as the thyroid gland, this is called an autoimmune disease. It may occur in people with a family history of thyroid diseases or with other autoimmune diseases, especially type 1 diabetes or reduced adrenal gland function. Lymphocytes (a type of white blood cell) move into the gland. These and thyroid antibodies slowly destroy the gland eventually leading to symptoms though this process can take many years. Symptoms are those of hypothyroidism, such as weight gain, increased sensitivity to cold, and fatigue; in addition, the thyroid may be markedly enlarged, in many cases causing a visible goitrefirm and rubbery but is not usually tender. It affects about 1 in 100 people in the population and is about 10 times more common in women than in men, most commonly affecting women in middle age.

Laboratory tests used to diagnose the disorder (in addition to thyroid function tests: TSH, T4, T3):

  • Anti-thyroid peroxidase (anti-TPO) antibody (positive; detects the presence of antibodies against a protein found in thyroid cells). These antibodies are not normally present, so a high value usually indicates autoimmune damage to the thyroid, including Hashimoto's thyroiditis and Graves’ disease

The treatment of Hashimoto's thyroiditis and any other cause of an underactive thyroid gland is with thyroid hormone, usually in the form of thyroxine. This treatment is called replacement therapy and is tailored and modified to meet the individual patient's requirements, guided by how the symptoms respond and the results of blood tests. Symptoms caused by an underactive thyroid gland usually respond well to thyroid hormone replacement therapy but in patients over 50 years or in those with heart disease it is usual to start on a very low dose and very slowly increase it until the appropriate dose is reached. It is usual to take thyroxine in the morning on an empty stomach although one recent study suggested that more thyroxine is absorbed in to the body if it is taken at bedtime.

Related Pages

On This Site
Conditions: Autoimmune disorders, Thyroid Diseases

Elsewhere on the Web
The National Library of Medicine Medlineplus article on Hashimoto’s thyroiditis