Sydenham's chorea.

Sydenham's chorea (SC) is the neurologic expression of acute rheumatic fever (ARF). Despite the declining incidence of ARF worldwide, it remains the most common cause of acute chorea in children. It is characterized by a combination of motor and nonmotor features. In addition to chorea, among the first are decreased muscle tone and tics. Nonmotor features include obsessions, compulsions, attention deficit, emotional lability, decreased verbal fluency, and executive dysfunction. Most patients present with nonneurologic features of ARF, such as carditis and arthritis. The pathogenesis is thought to involve streptococcus-induced antibodies which cross-react with antigens of the basal ganglia. The diagnosis is made on purely clinical grounds since there is no biological marker of the illness. The management is based on use of antichoreic agents, such as valproic acid and neuroleptics, and prophylaxis of new bouts of streptococcus infection with antibiotics. Although the motor features of SC come into spontaneous remission in the majority of patients, a significant proportion of individuals remain with persistent chorea.