Unilateral asterixis due to thalamic hemorrhage.

Unilateral asterixis involving the face, hand, and foot was caused by a contralateral hypertensive thalamic hemorrhage, confirmed by computerized tomography. In addition to the asterixis, loss of upward gaze and pupillary abnormalities suggested secondary midbrain compression. These findings raise the possibility that asterixis may be due to mesodiencephalic dysfunction, and suggest that unilateral asterixis can be used to localize focal lesions of this region of the brain.