Post-streptococcal autoimmune disorders of the central nervous system.

Group A Streptococcus can induce autoimmune disease in humans with particular involvement of the heart, joints, and brain. The spectrum of post-streptococcal disease of the central nervous system (CNS) has been widened recently and includes movement disorders (chorea, tics, dystonia, and Parkinsonism), psychiatric disorders (particularly emotional disorders), and associated sleep disorders. Neuroimaging and pathological studies indicate that the most vulnerable brain region is the basal ganglia. The immunopathogenesis of the disease is incompletely defined, and although there is some support for autoantibody-mediated disease, several conflicting studies cast doubt on the autoantibody hypothesis. It has been speculated that post-streptococcal autoimmunity has a role in common neuropsychiatric disease but the evidence is conflicting and routine screening of patients with Tourette syndrome and obsessive-compulsive disorder for post-streptococcal autoimmune abnormalities is not be recommended at present. However, post-streptococcal disorders of the CNS remain a useful model of neuropsychiatric disease, which may improve our understanding of abnormal movements and behaviours in children.