Sydenham chorea: An acute neurologic disorder that emerges several months following a streptococcal ("strep") infection, most frequently in children between the age of 5 and 15. There may be a history of a strep throat or a strep skin infection. There may similarly be a history of another sequel of a strep infection such as scarlet fever, glomerulonephritis or, especially, rheumatic fever.
The body movements, called chorea, in Sydenham disease are typically twisting. They are involuntary (not on purpose) and may involve jumping and dancing. They can become quite severe and interfere with normal walking and normal use of the arms as well as talking. The chorea tends especially to involve the distal limbs (the forearms and hands and the lower legs and feet) and is associated with hypotonia (decreased muscle tone) and emotional lability. Improvement usually occurs over a period of weeks or months but exacerbation (worsening) may occur without the recurrence of the strep infection. Sydenham's chorea can be treated with drugs.
There are various forms of Sydenham chorea: one form that just involves one side of the body (hemichorea), another form that involves muscular rigidity (termed paralytic chorea), etc. Sydenham chorea is also known as acute chorea, chorea minor, juvenile chorea, rheumatic chorea and postrheumatic chorea.
The word "chorea" refers to ceaseless rapid complex body movements that look well coordinated and purposeful but are, in fact, involuntary. Chorea was thought suggestive of a grotesque dance. The term "chorea" is derived from the Greek word "choreia" for dancing (as is choreography).
Thomas Sydenham (1624-1689) first described the condition. Sydenham left Oxford to fight in the English Civil Wars during which he met Thomas Coxe, a physician serving in the army, who inspired him to enter medicine. At the age of 38 he was licensed by the College of Physicians of London to practice medicine full-time and at 52 years of age he belatedly received his M.D. degree from Cambridge. He is considered the "English Hippocrates."
Sydenham chorea was also called St. Vitus dance.