Chapter 38 - Midbrain infarcts and hematomas

Summary

The arterial system supplying the midbrain is terminal for the midbrain itself, arising from the basilar artery and from the bifurcation of the basilar artery. According to magnetic resonance imaging (MRI)-based stroke registries, the midbrain was involved in 0.9% of strokes and 3% to 8% of posterior circulation infarcts. Oculomotor palsies are frequent in midbrain strokes and dominate the neurological picture. Combined upward- and downward-gaze palsy has been related to bilateral or unilateral midbrain infarcts. A lacunar infarct of the lateral midbrain affecting the pyramidal tract in the cerebral peduncle can cause pure motor stroke. Midbrain hematomas or infarcts that involve the sensory lemniscus have been reported as causes of pure sensory strokes. Bilateral, isolated small infarcts in the lateral midbrain involving the corticospinal tracts have been responsible for tetraplegia and mutism, leaving conscious patients with only gaze movements as a means to communicate.