Sydenham chorea and Hashimoto thyroiditis: an unusual association.

Sydenham chorea is an immune-mediated neuropsychiatric disorder associated with group A beta-hemolytic streptococci infection. The authors present a 12-year-old female patient with Sydenham chorea and Hashimoto thyroiditis. Although Hashimoto thyroiditis has been associated with other autoimmune disorders, the association of Sydenham chorea and Hashimoto thyroiditis has not been previously reported. Immunological processes are suggested to be implicated in the pathogenesis of this association; however, the exact mechanism remains unclear.