Chorea

Chorea is a hyperkinetic movement disorder that can manifest from a number of diseases. The Committee on Classification of the World Federation of Neurology describes chorea as a state of excessive, spontaneous movements that are irregularly timed, nonrepetitive, randomly distributed, and abrupt in character. These movements may vary in severity from restlessness with mild, intermittent exaggeration of gesture and expression, fidgeting hand motions, and unstable dance-like gait to a continuous flow of disabling, violent movements. Chorea, similar to choreography, refers to movements that resemble dancing. The causes of this symptom are extensive and include hereditary and acquired etiologies. A careful history, detailed examination, and some laboratory tests may narrow the list of differential diagnoses. Chorea is often accompanied by athetosis and, very rarely, ballism. Athetosis is a slower form of chorea. The slowed movements have a writhing or twisting motion. Chorea and athetosis are caused by lesions of the striatum, particularly the caudate or putamen. Ballism is a very severe form of chorea characterized by violent flinging of the extremities. The movements are involuntary and usually involve the limbs. Ballismus is usually unilateral and rarely bilateral. Hemiballismus classically results from an acute lesion in the contralateral subthalamic nucleus of the basal ganglia. Chorea is classified as "primary" when it is a feature of genetic conditions, most notably Huntington disease. The symptom is "secondary" when it is caused by other diseases affecting the basal ganglia, including toxic, metabolic, infectious, pharmacologic, neoplastic, vascular, autoimmune, and paraneoplastic disorders.