New Avenues in the Pathogenesis of Subarachnoid Hemorrhage

Background ̶Subarachnoid hemorrhage (SAH) remains a disease without any definitive treatment options. Research, to date, has concentrated on the pathophysiology of vasospasm. Recent evidence supports the concept of Early Brain Injury (EBI), a phenomena which may help to explain the complex pathophysiology seen in patients after a SAH. Summary ̶EBI aims to describe the pathophysiological events that occur in the brain within the fi rst seventy two hours after a SAH, before the onset of vasospasm. A number of pathways have been identifi ed which may play a role in the etiology of EBI. This review provides a brief synopsis of EBI and its implications for the future. Conclusions ̶EBI may represent a key event in the development of both vasospasm and Delayed Ischemic Neurological Deficit (DIND) after subarachnoid hemorrhage. Additional studies are required to determine the pathophysiology of EBI and to examine its role as a possible precursor to both vasospasm and DIND. Hirosaki Med.J. 61, Supplement:S157―S163,2010