A new, practical classification of traumatic subarachnoid hemorrhage

Introduction: Traumatic subarachnoid hemorrhage (tSAH), an increasingly recognized concurrent intracranial diagnosis, demonstrates a distribution of blood that is markedly different from nontraumatic SAH. This study serves to identity patterns of tSAH and their relationships to outcomes, allowing definition of a predictive classification specific to tSAH. Methods: Fifty-one centers from 11 countries collaborated in prospective data collection of 404 adults with severe head injury (GSC 4-8), who were then followed for six months. The initial CT scans were re-examined, characterizing tSAH by site and quantity. Outcomes were evaluated using the Glasgow Outcome Score (GOS). Favorable outcome includes GOS of good or moderate. Results: Patients with tSAH had 26% (82) mortality, those without tSAH had 13% (11); likewise, those with tSAH had 51% (160) favorable outcome, those without tSAH 78% (68) (p < 0.001). When tSAH occurred at an isolated site, mortality was 18% (29) and favorable outcome 59% (94). The location of the site did not result in variation. If the site of tSAH had such a large quantity of blood as to fill that structure or if there were two nonfilled sites of tSAH, mortality was 25% (41) and favorable outcome 51% (83). The presence of tSAH at three or more sites resulted in a 44% (28) mortality, and 28% (18) favorable outcome. The combination of two sites of tSAH including the tentorium filled with hemorrhage produced mortality of 31% (52) and favorable outcome of 44% (74). Discussion and Conclusions: The presence of tSAH results in a significant difference in both mortality and favorable outcome. The patterns of distribution and quantity of tSAH vary. The number of sites displaying tSAH has a direct relationship with outcome. When filled with blood, and in combination with another site of tSAH, the tentorium has a worse prognosis. We propose a new, simple, graded classification of tSAH, allowing rapid classification using initial CT scan, and providing information to aid in accurate outcome prediction.