A brain aneurysm is a bulging, weakened area in a blood vessel in the brain that can cause bleeding in the brain if it leaks or ruptures, known as a hemorrhagic stroke. Brain aneurysms develop when the walls of an artery in the brain become thin and weak, usually forming at branching points of arteries because these sections are the weakest. There are several reasons why this may happen, although an exact cause isnt always clear. The following factors can contribute to the weakening of an artery:

• Genetic connective tissue disorders that weaken artery walls
• Polycystic kidney disease (in which numerous cysts form in the kidneys)
• Smoking
• High blood pressure
• Cocaine abuse
• Severe head injury
• Alpha-glucosidase deficiency
• Alpha 1-antitrypsin deficiency
• Arteriovenous malformation (AVM)
• Coarctation of the aorta

Most unruptured brain aneurysms don’t cause symptoms, but if they become large enough, they can put pressure on nearby nerves or brain tissue, causing headaches, vision changes, numbness or tingling on the head or face, pain above and behind the eye, and seizures. A ruptured aneurysm can cause serious health problems such as hemorrhagic stroke, brain damage, coma, and even death.