subarachnoid hemorrhage

facts
		A subarachnoid hemorrhage is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain
		This may occur spontaneously, usually from a ruptured cerebral aneurysm, or may result from head injury
		Symptoms include an intense headache with a rapid onset ("thunderclap headache"), vomiting, and an altered level of consciousness

more information:		subarachnoid hemorrhage