Multifocal Atraumatic Convexity Subarachnoid Hemorrhage.

Background Multifocal convexity subarachnoid hemorrhage (cSAH) has generally been described in the setting of traumatic brain injury, however, it has also been reported in the absence of trauma in conditions such as with reversible cerebral vasoconstriction syndrome. We describe the clinical and radiographic characteristics of multifocal cSAH in an academic center. Methods We analyzed our single-center retrospective database of nontraumatic convexity subarachnoid hemorrhage from January 2015-January 2018. Convexity subarachnoid hemorrhage was defined as blood in one or more cortical sulci in the absence of trauma; patients with blood in the cisterns or Sylvian fissure were excluded. Multifocal location was defined as at least two distinct foci of hemorrhage occurring in two or more lobes. Clinical and neuroimaging data were collected. Results Out of 70 total patients with convexity subarachnoid hemorrhage, 13 cases were of multifocal convexity subarachnoid hemorrhage, occurring in 18.6% of all cases. The mean age was 58 years (SD = 14.7). Eleven patients were female. Seven patients had reversible cerebral vasoconstriction syndrome (RCVS)/posterior reversible encephalopathy syndrome (PRES), two had cerebral amyloid angiopathy (CAA), three had intrinsic coagulopathy, and one patient had endocarditis as the etiology of multifocal cSAH. Headache was the most common complaint, in eight (61.5%) patients. Conclusion Multifocal cSAH occurs in approximately 18.6% of all cSAH and can occur in the absence of trauma. In our larger cohort of all cSAH, CAA was the most common cause; however, multifocal cSAH is more commonly caused by RCVS/PRES spectrum. Clinicians should be aware that multifocal cSAH can occur in the absence of trauma, and may be a harbinger of RCVS/PRES, particularly in young patients with thunderclap headaches.