medial medullary syndrome; inferior alternating syndrome; hypoglossal alternating hemiplegia; Dejerine syndrome

Epidemiology

• rare
• < 1% of vertebrobasilar strokes

Pathology

• brainstem infarction of the medial medulla supplied by the anterior spinal artery
  • ipsilateral medullary pyramid, the medial leminiscus, & hypoglossal nerve fibers that pass through the medulla
  • the spinothalamic tract is spared (supplied by vertebral arteries & posterior inferior cerebellar arteries)
  • the trigeminal nucleus is also spared

Clinical manifestations

• ipsilateral deviation of the tongue on attempted protrusion
• contralateral limb weakness or hemiplegia
• contralateral loss of light touch, proprioception & vibration sense
• facial palsy (either side)
• ataxia, vertigo, nystagmus, dysphagia
• palatal & pharyngeal weakness are rare

More general terms

• syndrome
• brainstem infarction