Hemiballismus

Hemiballismus is a hyperkinetic movement disorder characterized by violent, flinging movements of one side of the body. Etiology is most commonly ischemic or hemorrhagic lesions of the contralateral subthalamic nucleus. Pathophysiology involves disruption of basal ganglia circuits, leading to loss of inhibitory pallidal output. Diagnosis is clinical, supported by neuroimaging. Management includes dopamine-depleting agents, antipsychotics, and supportive care; prognosis often improves as lesions stabilize.