Nonaneurysmal Subarachnoid Hemorrhage: A Review of Clinical Course and Outcome in Two Hemorrhage Patterns

Linda L. Herrmann; Joseph M. Zabramski


J Neurosci Nurs. 2007;39(6):135-142. 

In This Article

Nonaneurysmal Subarachnoid Hemorrhage

For the purposes of this article, nonaneurysmal subarachnoid hemorrhage is defined as nontraumatic, spontaneous SAH of unknown etiology. The term angiographically negative SAH, often used interchangeably with NASAH, refers to the fact that conventional cerebral angiography fails to reveal a source for the hemorrhage. Patients with NASAH are often divided into two groups on the basis of the pattern of SAH—perimesencephalic or aneurysmal—seen on the initial computed tomography (CT) scan (Alexander et al., 1986; Brilstra et al., 1997; Greenberg, 2001; Rinkel, Wijdicks, Hasan, et al., 1991). In both groups, the clinical presentation may be indistinguishable from that of a patient with a ruptured intracranial aneurysm.