Subarachnoid hemorrhage is bleeding in the space between your brain and the surrounding membrane (subarachnoid space). Bleeding usually results from the rupture of an abnormal bulge in a blood vessel in your brain (brain aneurysm).

Sometimes an abnormal tangle of blood vessels in your brain (arteriovenous malformation), trauma or other events cause bleeding. A subarachnoid hemorrhage may lead to permanent brain damage or death if not treated.

Aug. 19, 2014