Chorea

Chorea sancti viti (Latin for "St. Vitus' dance") is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias. The term chorea is derived from a Greek word khoreia (a kind of dance), as the quick movements of the feet or hands are vaguely comparable to dancing or piano playing.

Presentation
Chorea is characterized by brief, irregular contractions that are not repetitive or rhythmic, but appear to flow from one muscle to the next.

These 'dance-like' movements of chorea (from the same root word as "choreography") often occur with athetosis, which adds twisting and writhing movements.

Causes
Chorea can occur in a variety of conditions and disorders.
 * Chorea is a primary feature of Huntington's disease, a progressive, hereditary movement disorder.
 * Twenty percent of children and adolescents with rheumatic fever develop Sydenham's chorea as a complication.
 * Chorea may also be caused by drugs (levodopa, anti-convulsants, anti-psychotics), metabolic disorders, endocrine disorders, and vascular incidents.

Ballism
When chorea is serious, slight movements will become thrashing motions; this form of severe chorea is referred to as ballism. Walking may become peculiar, and include odd postures and leg movements. Unlike ataxia and dystonia, which affect the quality of voluntary movements or parkinsonism, which is a hindrance of voluntary movements, the movements of chorea and ballism occur on their own, without conscious effort.

Treatment
There is no standard course of treatment for chorea. Treatment depends on the type of chorea and the associated disease.