Isolated spinothalamic sensory impairment of the left arm following contralateral medullary infarction: a case report.

Cerebral MRI with thin brainstem slices (thickness 2 mm) detected a small ischemic lesion in the right dorsolateral and ventral medulla ( fig. 1 ). MR angiography showed occlusion of the right vertebral artery ( fig. 2 ), as did duplex sonography. Sensory evoked potentials from the median and tibial nerves were not delayed, providing evidence of normal lemniscal sensation. The patient was discharged with the diagnosis of a lacunar brainstem stroke following occlusion of the right vertebral artery. Medication with aspirin and simvastatin was initiated for the purpose of secondary prevention.