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Brainstem strokes

Learning objectives

  • Types of Brainstem strokes


The brainstem is vulnerable to both ischaemic and haemorrhagic strokes. Out come is very variable depending if strokes are unilateral or bilateral. What is important to note is that despite the narrow brainstem the arterial supply is usually from the vertebral or basilar arteries and lesions tend to respect and not cross the midline. It is however possible for a very diseased basilar and especially a top of the basilar syndrome to cause multiple bilateral and asymmetrical strokes. Brainstem stroke is not a term to be used only in its most general sense. Cranial nerves and other signs should help one to localise to midbrain, pons and medulla and MRI will support this and the specificity of the location - ventral or dorsal pons etc. Upper or lower midbrain, medial or lateral medulla. In the 19th century when stroke location and clinical appearance could only be precisely diagnosed by post mortem french neuroanatomists described and named a collection of brainstem strokes and their clinical signs. These are often used in texts. However the eponymous terms are not important if the understand how the anatomy and clinical correlate.

Midbrain: Weber syndrome
  • Anterior brainstem infarction
  • Contralateral hemiparesis
  • ipsilateral IIIrd nerve palsy
Midbrain:Benedikt syndrome
  • Paramedian midbrain (red nucleus)
  • Contralateral cerebellar dysfunction
  • Partial ipsilateral IIIrd nerve nucleus
Midbrain:Nothnagel syndrome
  • Dorsolateral midbrain lesion
  • Complete contralateral loss of sensation
  • Ipsilateral Horner's syndrome
  • Ipsilateral IIIrd nerve palsy
  • Ipsilateral cerebellar signs
Basilar artery branches to Medial Midbrain
  • ? IIIrd nerve palsy
  • C|L hemiparesis and hemiataxia or tremor
P1 segment of PCA supply
  • Lateral Midbrain ? C|L hemi-sensory loss
  • Vertical gaze palsies
Pons - Millard-Gubler syndrome
  • Pontine lesion involving VIth and VII
  • Contralateral hemiparesis
  • Ipsilateral 6th and 7th
Medulla: Medial Medullary Syndrome
  • Ipsilateral paralysis and tongue atrophy
  • C/L arm and leg weakness
  • C'L loss of Proprioception and touch sensation
Medulla: Lateral Medullary Syndrome
  • Ipsilateral pain and numbness to face
  • Ipsilateral limb ataxia, hiccough
  • Vertigo nausea and vomiting
  • Dysphagia, hoarseness
  • Ispilateral limb and trunk senation reduced
  • C/L loss of temperature sensation

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