[Hemiballism-hemichorea caused by a putaminal hemorrhage with worsening after smoking--a case report].

A 65-year-old hypertensive man was admitted because of abnormal involuntary movements which had an onset one month prior to the admission. Neurological examination revealed an alert and intelligent male in no acute distress. Cranial nerves appeared intact except for dysarthria. His gait was wide-based. He had hemiballism-hemichorea in his left upper and lower extremities. Cranial CT scans revealed a high density area confined to the right putamen. After admission, his involuntary movements slowly improved without medication. After near complete disappearance of his abnormal movements two weeks after admission, he noted that smoking induced choreic movement in his left side transiently. The involuntary movement ceased soon after upon stopping smoking. This was repeatedly observed not only by him but also by us. Our observation may indicate that the inhibition of the subthalamic nucleus as the result of the decrease of the putaminal output to the external segment of the globus pallidus will induce hemiballism. The effect of smoking on his involuntary movements can be understood as a result of increase in the dopamine release from the nigrostriatal terminals induced by nicotine.