Hemiballismus.

Hemiballismus is a rare movement disorder that can be life threatening in the absence of a rational treatment approach. The pathologic abnormality lies in the subthalamic nucleus and its afferent or efferent connections. Before the advent of effective pharmacologic treatments, patients with hemiballismus had a dismal prognosis, with physical exhaustion, injuries, and medical complications often leading to death. Advances in pharmacologic management and emphasis on supportive measures have improved the outlook for these patients, with most now surviving. Hemiballismus tends to diminish or resolve spontaneously over several months. Treatment approaches should be vigorous during the acute phase but often may be discontinued after 6 months to 1 year. Surgical treatment of hemiballismus appears promising and should be reserved for the patient with persistent movements whose disease is refractory to medical management.