Acute Infectious Thyroiditis (Acute Suppurative Thyroiditis)
Acute infectious thyroiditis is a rare inflammatory thyroid disease that is caused by bacterial or fungal infection. Pyriform sinus fistula is an underlying abnormality most commonly found in patients with acute infectious thyroiditis, and this is the route of the infection in such patients. This congenital fistula is considered an embryonic remnant related to the migration of the C cells from their anlage, the ultimobranchial body, to the thyroid. In detecting pyriform sinus fistulae, barium swallow studies are more sensitive than any other modality. A careful search of the hypopharynx discloses an internal fistula originating from the apex of the pyriform recess. The abscess or acute inflammation present in patients with a pyriform sinus fistula readily subsides, if adequate drainage is performed and intravenous empiric broad-spectrum antibiotics are given. Because recurrence of the inflammation is very common, a definitive treatment such as fistulectomy or chemocauterization should be performed. As acute infectious thyroiditis through a pyriform sinus fistula may mimic subacute thyroiditis in early period of the inflammation, differential diagnosis is important to refrain from erroneous prescription of prednisolone, which aggravates the inflammation. Other rare types of acute infectious thyroiditis include infected thyroid nodules and injury or perforation of the cervical esophagus.
KeywordsAcute infectious thyroiditis Acute suppurative thyroiditis Pyriform sinus fistula Thyrotoxicosis Chemical cauterization C cell Ultimobranchial body Embryonic remnant Route of infection Trumpet maneuver Fistulectomy Nonomura method Infected thyroid nodule Foreign body Esophageal cancer