Thyroiditis

Thyroiditis is an inflammation of the thyroid gland caused by an autoimmune disorder or a viral infection. In its first phase, this inflammation leads to the release of thyroid hormone from within the gland, causing hyperthyroidism and, subsequently, to a decrease in thyroid function, leading to hypothyroidism. This can be permanent (chronic thyroiditis) or temporary (subacute thyroiditis, postpartum thyroiditis).  It can also be classified according to whether it is associated with pain or not, the presence of goitre, or altered thyroid function. 

Subacute postviral thyroiditis is the most common cause of pain in the thyroid area, followed by subacute postpartum thyroiditis.  Hashimoto's thyroiditis is chronic and is the most common cause of hypothyroidism in our society. 

Thyroiditis is more common in women, but its prevalence and the age of onset vary depending on the cause.