What is chorea?
Chorea, also called St. Vitus's dance, is the acute disturbance of the central nervous system characterized by involuntary muscular movements of the face and extremities. Chorea is the ceaseless occurrence of rapid, jerky involuntary movements. The face, tongue and limbs may all be involved. There is associated hypotonia and inability to maintain a posture. Choreiform movements generally occur at right angles to the axis of a limb. Chorea is brief, purposeless
involuntary movements of the distal extremities and face, which may merge imperceptibly into purposeful or semipurposeful acts that mask the involuntary motion. Chorea usually affects both sides of the body, but in some instances only one side of the body is involved. This is referred to as hemichorea.
The disease, known also as Sydenham's chorea (not to be confused with Huntington's disease, a hereditary disease of adults that is sometimes called Huntington's chorea), is usually, but not always, a complication of rheumatic fever. Sydenham's chorea, a disease of children, especially females, usually appears between the ages of 7 and 14. Facial grimacing and jerking movements persist for 6 to 10 weeks and sometimes recur after months or even years. Eventually the symptoms disappear. Although there is no specific treatment, sedatives and tranquilizers are helpful in suppressing the involuntary movements. Technically, it is sometimes called chorea minor or juvenile chorea to distinguish it from several less common choreas, chorea also being a general term for continuous, involuntary jerking movements.
Chorea and athetosis often occur together (choreoathetosis). The most important cause of chorea is Huntington's disease. Other causes include thyrotoxicosis, SLE affecting the CNS, and drugs (eg, antipsychotics). Chorea and athetosis are manifestations of dopaminergic overactivity in the basal ganglia--the antithesis of Parkinson's disease. The role of cholinergic and other systems is less clear in the pathophysiology of the dyskinesias than in that of Parkinson's disease.