Subarachnoid hemorrhage (SAH), intracranial hemorrhage into the subarachnoid space, may be aneurysmal or nonaneurysmal. Causes of SAH are uncertain, risk factors include family history of aneurysms, age, alcohol, cigarettes, and hypertension. Warning signs are a severe and sudden headache, emesis, and developing stiff neck. Annual incidence in North America is approximated at 10 cases per 100,000 people; nonaneurysmal SAH represents around 15 percent of the population. Computed tomography (CT) is used to test for SAH, followed by lumbar puncture. Catheter cerebral angiography is the current standard for the diagnosis of aneurysm SAH. SAH results in death or disability (around 55 percent); nonaneurysm SAH has a better outcome. Early diagnosis and repair of SAH minimizes the risk of rebleeding. Aneurysm surgery, anticonvulsants, calcium antagonists, neuroprotectants, and prevention of vasospasm help manage ruptured cerebral aneurysms and improve SAH prognosis.
Subarachnoid hemorrhage is defined as intracranial hemorrhage into the subarachnoid space (1:750). Subarachnoid hemorrhage from a ruptured intracranial or cerebral aneurysm is also referred to as aneurysmal subarachnoid hemorrhage (SAH) (5). Nonaneurysmal SAH is also included (8).
Causes of aneurysm formation or rupture remain uncertain. Gender and race are not shown to be predictors of aneurysm rupture. Hypertension is an independent risk factor for rupture of a previously intact aneurysm (7). Most studies of risk factors combine SAH and intracerebral hemorrhage (ICH), forming the category of hemorrhagic stroke; these studies also include other causes of hemorrhages such as nonaneurysmal SAH. Risk factors for SAH are identified. Alcohol consumption and cigarette smoking increase the risk for SAH. Potential risk factors for hemorrhagic stroke are anticoagulant treatment, aspirin use, thrombolytic therapy, and amphetamine or cocaine use. These factors may s...