The two broad categories of stroke, hemorrhage and ischemia, are diametrically opposite conditions: hemorrhage is characterized by too much blood within the closed cranial cavity, while ischemia is characterized by too little blood to supply an adequate amount of oxygen and nutrients to a part of the brain .
Each of these categories can be divided into subtypes that have somewhat different causes, clinical pictures, clinical courses, outcomes, and treatment strategies. As an example, intracranial hemorrhage can be caused by intracerebral hemorrhage (ICH, also called parenchymal hemorrhage), which involves bleeding directly into brain tissue, and subarachnoid hemorrhage (SAH), which involves bleeding into the cerebrospinal fluid that surrounds the brain and spinal cord .
This topic will review the classification of stroke. The clinical diagnosis of stroke subtypes and an overview of stroke evaluation are discussed separately. (See "Clinical diagnosis of stroke subtypes" and "Overview of the evaluation of stroke".)
Stroke is classified into two major types:
●Brain ischemia due to thrombosis, embolism, or systemic hypoperfusion