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

It is divided into two broad categories:

  • ischemic stroke  (80% )
  • hemorrhagic stroke (15%)
  • Hemorrhage may be primary (usually as a result of hypertension or cerebral amyloid angiopathy) or secondary (the result of an underlying lesion such as a vascular malformation or tumor).


    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 can easily be confused for "hemorrhagic transformation of an ischemic stroke". In fact, an argument can be made to abandon the term "hemorrhagic stroke" entirely .