Thyroiditis is the inflammation of the thyroid gland. The thyroid gland is located on the front of the neck below the laryngeal prominence, and makes hormones that control metabolism. There are many different signs and symptoms for thyroiditis, none of which are exclusively limited to this disease. Many of the signs imitate symptoms of other diseases, so thyroiditis can sometimes be difficult to diagnose. Common hypothyroid symptoms manifest when thyroid cell damage is slow and chronic, and may include fatigue, weight gain, feeling "fuzzy headed", depression, dry skin, and constipation. Other, rarer symptoms include swelling of the legs, vague aches and pains, decreased concentration and so on. When conditions become more severe, depending on the type of thyroiditis, one may start to see puffiness around the eyes, slowing of the heart rate, a drop in body temperature, or even incipient heart failure. On the other hand, if the thyroid cell damage is acute, the thyroid hormone within the gland leaks out into the bloodstream causing symptoms of thyrotoxicosis, which is similar to those of hyperthyroidism. These symptoms include weight loss, irritability, anxiety, insomnia, fast heart rate, and fatigue. Elevated levels of thyroid hormone in the bloodstream cause both conditions, but thyrotoxicosis is the term used with thyroiditis since the thyroid gland is not overactive, as in the case of hyperthyroidism. Thyroiditis is generally caused by an immune system attack on the thyroid, resulting in inflammation and damage to the thyroid cells. This disease is often considered a malfunction of the immune system and can be associated with IgG4-related systemic disease, in which symptoms of autoimmune pancreatitis, retroperitoneal fibrosis and noninfectious aortitis also occur. Such is also the case in Riedel thyroiditis, an inflammation in which the thyroid tissue is replaced by fibrous tissue which can extend to neighbouring structures. Antibodies that attack the thyroid are what causes most types of thyroiditis.
Pierre Magistretti, Thibault Adrien Kuntzer