Brain aneurysms are balloon-like formations of blood that push on the brain artery walls and weaken them, sometimes to the point of rupture. “Wear and tear” on the arteries, genetic tendencies, cigarette smoking, alcohol abuse, oral contraceptives, injury and/or infection can all contribute to the formation of a brain aneurysm. Pain behind the eye, localized headache, dilated pupils and double vision are all warning signs of a brain aneurysm. A ruptured brain aneurysm often causes the above symptoms plus nausea, loss of sensation, dizziness, vomiting, sensitivity to light and stiffness in the neck. A ruptured brain aneurysm, also called a subarachnoid hemorrhage, will leak blood into the brain, possibly causing brain damage and, in about 50% of cases, death. Subarachnoid hemorrhage must be treated immediately; a CT scan can help doctors determine the extent of bleeding, and decide how to best proceed next.