Acute infectious thyroiditis
（重定向自Acute thyroiditis）
Acute infectious thyroiditis (AIT) also known as suppurative thyroiditis, microbial inflammatory thyroiditis, pyrogenic thyroiditis and bacterial thyroiditis.
The thyroid is normally very resistant to infection. Due to a relatively high amount of iodine in the tissue, as well as high vascularity and lymphatic drainage to the region, it is difficult for pathogens to infect the thyroid tissue. Despite all this, a persistent fistula from the piriform sinus may make the left lobe of the thyroid susceptible to infection and abscess formation. AIT is most often caused by a bacterial infection but can also be caused by a fungal or parasitic infection, most commonly in an immunocompromised host.