A Systematic Approach to the Definition of Stroke

The 24-hour time-line for symptomsin the current definition of stroke is arbitrary. Moreover, this definition does not include silent stroke, encourage acute stroke therapy and consider dramatic recovery after successful therapy. Silent stroke, which is five times more common than symptomatic stroke, is a risk factor for future stroke and is associated with adverse neurological and cognitive functions. Whilst pathological confirmation remains the gold standard in defining stroke and its underlying etiology, widely available neuroimaging has greatly obviated the need for post-mortem examination. Modern multimodal neuroimaging permits confirmation of infarction and/or hemorrhage in the central nervous system, reveals the location and size of the vascular lesion, excludes the stroke mimics and evaluates the relevant cerebrovascular anatomy. Nevertheless, neuroimaging may be limited to anunenhanced computed tomography of the brain. Furthermore, stroke symptoms may resolve either spontaneously or upon successful thrombolysis despite development of new infarction or hemorrhage. It was timely for the American Heart Association and American Stroke Association to publish an updated definition of stroke in July 2013. This updated definition of stroke incorporates both clinical and tissue criteria and comprises of ten possible definitions of stroke. The latter include silent infarction and silent hemorrhage. One problem of the updated definition is major overlaps among the definitions. Another problem is the non-systematic nature of the definitions. This editorial proposes a comprehensive and systematic approach to the definition of stroke by incorporating the following factors: level of certainty, presence and nature of symptoms, duration of symptoms, pathological types, and underlying etiologies.