A subarachnoid hemorrhage occurs when blood leaks into the space between two of the membranes surrounding the brain. A swollen blood vessel, or aneurysm, usually ruptures and causes the condition.

Nontraumatic subarachnoid hemorrhage is a neurologic emergency characterized by the extravasation of blood into the spaces covering the central nervous system that are filled with cerebrospinal fluid.

to the editor: A 45-year-old woman with a history of migraines and a recent diagnosis of hypertension presented with a two-day history of increasing headache. She had taken over-the-counter ...