[Hemiballism. Description of a clinical case in childhood]

Biballism is an infrequent hyperkinetic disorder characterized by involuntary, intermittent, violent, uncontrollable contractions of the proximal muscles of the limbs. Biballism is classically ascribed to a lesion in the controlateral subthalamic nucleus or its connections but other causes have been reported. These include infections (bacterial, viral parasitic), cerebrovascular lesions, tumors, toxics, and systemic disease (systemic lupus erythematosus). Although poorly understood, the pathophysiology of hemiballism is widely believed to involve hyperactivity of the dopaminergic system. The prognosis of these abnormal movements, formerly poor, has been improved by the use of neuroleptics and drugs acting on the different neurotransmitter systems. A unique case of biballism at resolution of a febrile coma in a 4 1/2 year old is reported. The EEG showed diffuse slow waves. A hyperdense lesion was visible in the right thalamic region on the cerebral CT scan. The magnitude of the abnormal movements decreased under haloperidol. The etiology of this case of biballism is discussed.