Post-Streptococcal autoimmune neuropsychiatric disease presenting as paroxysmal dystonic choreoathetosis

Paroxysmal dystonic choreoathetosis (PDC) is an episodic, non‐kinesogenic, extrapyramidal movement disorder. It is postulated that PDC is an ion channel disorder. We describe a sporadic case of paroxysmal dystonic choreoathetosis occurring after streptococcal pharyngitis. The episodes were characterized by abrupt‐onset dystonic posturing, choreoathetosis, visual hallucinations and behavioral disturbance. Each episode lasted between 10 minutes and 4 hours, and occurred up to 4 times per day. In between attacks, examination was normal. The episodes waxed and waned in frequency during a 6‐month illness. Magnetic resonance imaging of the brain was normal. Post‐streptococcal neuropsychiatric disease has a proposed autoimmune etiology, which is supported by the presence of serum antibasal ganglia antibodies. Western immunoblotting of this case's serum demonstrated antibody binding to a basal ganglia antigens of molecular weight 80 kDa and 95 kDa. Immunohistochemistry examination demonstrated specific antibody binding to large striatal neurones. We propose that autoantibodies produced in post‐streptococcal neuropsychiatric disease cause alteration in neurotransmission, possibly secondary to ion channel binding. © 2002 Movement Disorder Society