A case of acute suppurative thyroiditis caused by a mixed infection of Actinomyces and viridans streptococci

Actinomyces and viridans streptococci are very rare causes of acute suppurative thyroiditis. To date, mixed infections of Actinomyces and viridans streptococci have not been reported in the literature. Here, we describe a case of acute suppurative thyroiditis caused by a mixed infection of Actinomyces and viridans streptococci, and present a review of the literature. Briefly, a 20-year-old female was admitted to the hospital with anterior neck swelling, pain, and a fever that lasted for 2-days following an upper respiratory tract infection. A neck CT scan revealed a lobulated low-density mass in the thyroid gland. The mass was presumed to be an abscess, and aspiration cytology was performed, which showed neutrophillic exudate with Actinomyces. Surgical drainage was then completed, and viridans streptococci were cultured in the pus. After systemic antibiotics were administered for 10 days, the patient was discharged with symptomatic improvement. At the 6-month follow-up, ultrasonographic findings of the thyroid revealed no persistent lesions.