title: Angiogram-negative subarachnoid hemorrhage: outcomes data and review of the literature.
abstract: Spontaneous subarachnoid hemorrhage (SAH) is most commonly caused by rupture of a saccular aneurysm or other structural pathologies. Occasionally, no structural cause for the hemorrhage can be identified by radiographic imaging. These hemorrhages, termed angiogram-negative SAH, are generally considered to have a better prognosis than aneurysmal SAH. Angiogram-negative SAH subgroups include benign perimesencephalic SAH (PMH) and aneurysmal-type SAH. Outcome data for these subgroups differ from those for the group as a whole. We report data for 31 patients who presented to our institution from 2006 to the present. We performed a retrospective chart review, and report outcome data that include rates of rehemorrhage, hydrocephalus, vasospasm, permanent ischemic deficits, headaches, and outcomes based on modified Rankin Scale scores. We also performed a review of the literature and meta-analysis of the data therein. We compared rates of complications in the PMH subgroup and the diffuse-type hemorrhage subgroup. The chart review revealed no poor outcomes and no rehemorrhages in the patients with PMH. In the diffuse hemorrhage subgroup, 1 patient had a rehemorrhage and 2 patients had a poor outcome. Our literature review found an OR of 6.23 for a good outcome for PMH versus diffuse-type hemorrhage, and an OR of 2.78 for rehemorrhage in PMH versus diffuse-type hemorrhage. Angiogram-negative SAH is not a benign entity. Complications are present but are significantly reduced, and outcomes are improved, compared with aneurysmal SAH.
authors.affiliation: Section of Neurosurgery, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA. smboswel@unmc.edu
authors.forename: Scott
authors.initials: S
authors.lastname: Boswell
authors.forename: William
authors.initials: W
authors.lastname: Thorell
authors.forename: Steve
authors.initials: S
authors.lastname: Gogela
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Lyden
authors.forename: Dan
authors.initials: D
authors.lastname: Surdell
mesh_terms: D002545:Brain Ischemia / Q000209:etiology; D002533:Cerebral Angiography; D018450:Disease Progression; D005260:Female; D006261:Headache / Q000209:etiology; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging*; D013997:Time Factors; D020301:Vasospasm, Intracranial / Q000209:etiology