Internal fistula as a route of infection in acute suppurative thyroiditis.

Seven cases of acute suppurative thyroiditis are described. Six patients had a recurrent painful swelling of the left anterior neck and one was seen at her first episode of the disease. A barium meal revealed a fistula originating from the apex of the left pyriform sinus in all cases. The fistula, a remnant of the fourth pharyngeal pouch, thus seems to be a common route of infection in acute suppurative thyroiditis, allowing bacterial infection to begin in the perithyroidal space and spread to the thyroid gland. Complete extirpation of the fistula is required for a permanent cure.