Last revised by Frank Gaillard on 26 Apr 2023

A stroke is a clinical diagnosis that refers to a sudden onset focal neurological deficit of presumed vascular origin.

Stroke is generally divided into two broad categories 1,2:

  1. ischemic stroke (87%)
  2. hemorrhagic stroke (13%)


The term "stroke" is ambiguous and care must be taken to ensure that precise terminology is used. This is particularly the case for "hemorrhagic stroke" which although is often used synonymously with intracerebral hemorrhage, has a broader definition to many authors and organizations to also include subarachnoid hemorrhage 1. Additionally, "hemorrhagic stroke" can easily be confused with "hemorrhagic transformation of an ischemic stroke". An argument has been made to abandon the term "hemorrhagic stroke" entirely 3.

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Cases and figures

  • Figure 1: cerebral vascular territories
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  • Case 1: MCA territory infarction
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  • Case 2: pontine infarct
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  • Case 3: thalamic lacunar infarct
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  • Case 4: basal ganglia ICH
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  • Case 5: lobar ICH
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