Thyroiditis refers to either acute or slowly developing inflammation of the thyroid gland, a small butterfly-shaped gland in the front of the neck, below the Adam’s apple. This gland produces hormones (thyroid hormones) that play an important role in controlling the body’s metabolism. When the thyroid becomes inflamed, it can become enlarged (goiter) and overactive (hyperthyroidism), or it can shrink (atrophy) as it loses activity and function (hypothyroidism). Thyroiditis is often characterized by a period of excessive thyroid hormone production followed by a period of inadequate thyroid hormone production. In some cases, thyroid function is not affected.
There are three main types of thyroiditis:
- Chronic thyroiditis (from autoimmune origin)
- Subacute thyroiditis (from viral infection)
- Acute suppurative thyroiditis (from bacterial infection)
The most common type of chronic thyroiditis is Hashimoto’s disease, an autoimmune disease in which the immune system attacks the body’s own tissues; in this case the tissues of the thyroid gland are being attacked by antithyroid antibodies produced by the immune system. As a result, the thyroid gland becomes unable to produce enough hormones.
Hashimoto’s disease is often not diagnosed until it has suppressed thyroid production, resulting in hypothyroidism. As in other autoimmune diseases, stress is believed to be a factor in Hashimoto’s disease, but the condition is also associated with other autoimmune diseases such as type 1 diabetes, pernicious anemia, Addison’s disease, rheumatoid arthritis, lupus, chronic hepatitis, hypoparathyroidism, hypopituitarism, and vitiligo. It is also linked to genetic conditions such as Down syndrome, Turner’s syndrome, and Klinefelter’s syndrome.