The worldwide incidence of
spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to
intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the
subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early
aneurysm repair, administration of
nimodipine, and advanced
intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits,
mood disorders,
fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake
aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral
nimodipine. The most common complications are
aneurysm rebleeding,
hydrocephalus, delayed
cerebral ischemia, and medical complications (
fever,
anemia, and
hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.