Hashimoto's thyroiditis

Hashimoto's thyroiditis, the most common form of thyroiditis, is an autoimmune disease where the body's own antibodies fight the cells of the thyroid. Also known as Hashimoto's disease, it is named after the Japanese physician, Hakaru Hashimoto (1881–1934) of the medical school at Kyushu University, who first described the symptoms in 1912. This disorder is believed to be the most common cause of primary hypothyroidism in North America. It is more prevalent (8:1) in women than in men, and its incidence increases with age. A family history of thyroid disorders is common, with the HLADR5 gene most strongly implicated conferring a relative risk of 3 in the UK. The genes implicated vary in different ethnic groups and the incidence is increased in patients with chromosomal disorders, including Turner's, Down, and Klinefelter's syndromes.

In many cases, Hashimoto's thyroiditis usually results in hypothyroidism, although in its acute phase, it can cause a transient hyperthyroid state.

Physiologically, antibodies to thyroid peroxidase and/or thyroglobulin cause gradual destruction of follicles in the thyroid gland. Accordingly, the disease can be detected clinically by looking for these antibodies in the blood. It is also characterised by invasion of the thyroid tissue by leukocytes, chiefly T-lymphocytes.

Treatment is with daily thyroxine, with the sodium salt of thyroxine liothyronine given when the need to raise levels of circulating thyroxine is urgent.

Symptoms of Hashimoto's thyroiditis include symptoms of hypothyroidism and a goitre.

In European countries an atrophic form of autoimmune thyroiditis (Ord's thyroiditis) is more common than Hashimoto's thyroiditis.