Non-traumatic subarachnoid hemorrhage

Non-traumatic subarachnoid hemorrhage (SAH) has distinct risk factors, demographics, and treatment from other forms of stroke. Spontaneous SAH, mostly aneurysmal, accounts for about 2-5% of all strokes, afflicting 37,500 cases of stroke per year in the United States [1]. A cerebral aneurysm is an outpouching of the brain arteries that eventually ruptures. The incidence of non-traumatic aneurysmal SAH has remained stable over the past 30 years [2]. Although the incidence of non-traumatic SAH varies from region to region, the aggregate worldwide incidence is about 10.5 per 100,000 person years [3, 4]. Women have a 1.6 times (95% confidence interval [CI] 1.5-2.3) higher risk than men [5] and people of African descent a 2.1 times (95% CI 1.3-3.6) higher risk than whites [6]. The major risk factors for non-traumatic SAH include cigarette smoking, hypertension, cocaine use, and habitual heavy alcohol intake [7]. Other factors, such as a family history of first-degree relatives with the disease and heritable connective-tissue disorders, also play a role [7].