[A patient with choreoathetosis of the left upper extremity due to acute cerebral infarction].

A 71-year-old woman was admitted to our hospital because of involuntary movement of the left upper extremity. MR image of the brain 15 days after the onset revealed the low intensity in right posterior limb of internal capsule. The lesion was surrounded by thalamus, subthalamic nucleus, and globus pallidus with enhancement by Gd-DTPA. Surface EMG revealed irregular grouped discharge in short duration and grouped discharge in long duration in the left upper extremity. Those features are compatible with one of choreoathetosis. Choreoathetosis due to cerebral infarction in acute phase is rare. We discussed pathophysiology of this involuntary movement due to lacunar infarction of posterior limb of internal capsule in acute phase.