The brain relies on two sets of major arteries to supply it with blood, and it's critical that they stay healthy. Aneurysms are when a spot on the wall of a brain artery bulges, like a weak part of a bike inner tube. Over time, this spot loses integrity, continuing to weaken and eventually rupturing. Blood then escapes into the space surrounding the brain, and often, surgery is then needed to repair it.
Usually, there are no symptoms of brain aneurysms. They strike quickly and can be extremely dangerous. Headaches, dilated pupils, pain behind and above the eye and double vision, difficulty speaking and weakness might be felt when an aneurysm occurs. If these symptoms come on quickly, it is recommended to seek immediate medical attention.
The video from the Mayo Clinic discusses a few risk factors for brain aneurysms, including being over the age of 40. It is estimated by the Brain Aneurysm Foundation that one in fifty people are carrying an unruptured brain aneurysm.