The diagnosis is subarachnoid hemorrhage due to ruptured aneurysm. The term subarachnoid hemorrhage (SAH) refers to extravasation of blood into the subarachnoid space between the pial and arachnoid membranes. Intracranial saccular aneurysms ("berry aneurysms") represent the most common etiology of nontraumatic SAH; about 80% of cases of SAH result from ruptured aneurysms.The diagnosis is confirmed radiologically urgent CT scan without contrast.