A case of acute suppurative thyroiditis caused by Streptococcus suis infection

Introduction: Acute suppurative thyroiditis (AST) is an uncommon but potentially life-threatening condition. The majority of AST cases are caused by bacterial infection. Streptococcus suis is a swine pathogen that mostly causes meningitis and septicemia. To date, AST caused by Streptococcus suis has not yet been reported.

Case report: A 64-year-old Thai female presented with rapid enlargement of a preexisting large left thyroid nodule without compressive symptoms for one week. She had a fever and purulent discharge spontaneously drained from her fluctuated mass. Her thyroid function workup revealed elevated serum thyroid hormone levels with suppressed thyrotropin levels. Thyroid scan and uptake showed functioning thyroid tissue in the left lobe of the thyroid. Prompt antibiotic therapy and drainage were performed, and this led to significant improvement. However, thyroid cancer was suspected, and the patient underwent lobectomy. Pus cultures grew Streptococcus suis. She had a history of raw pork product consumption.

Conclusions: This case highlights the importance of correct identification of pathogens for proper antibiotic therapy. AST caused by Streptococcus suis should be included in the differential diagnosis, especially in areas with a high prevalence of Streptococcus suis diseases.