“…The normal angiographic findings in these instances are consistent with a venous origin of the bleeding, which can occur due to the rupture of a prepontine or interpeduncular vein (Hashimoto et al, 2000). Approximately 5% of SAH are associated with other medical conditions such as arteriovenous malformation, intracranial artery dissections, mycotic aneurysms, bleeding disorders, reversible cerebral vasoconstriction syndrome, vasculitis, moyamoya disease, cerebral amyloid angiopathy, or drug abuse (Cabral et al, 2013; Cuvinciuc et al, 2010; Rinkel et al, 1993; Santos Carvalho et al, 2013; Venti, 2012; Viswanathan et al, 2012). This review focuses only on current neurobiological knowledge of aneurysmal SAH.…”