Historically called St Vitus's dance, this type of CHOREA is a disease of the central nervous system that occurs up to six months after RHEUMATIC FEVER. It is probably an inflammatory complication of a β-haemolytic streptococcal infection (see STREPTOCOCCUS). The patient presents with jerky, purposeless, involuntary movements of a limb and tongue typically lasting 6–8 months with full recovery.