A cerebral aneurysm is the dilation, bulging, or ballooning out of part of the wall of a vein or artery in the brain. Cerebral aneurysms can occur at any age, although they are more common in adults than in children and are slightly more common in women than in men.

Emergency treatment for individuals with a ruptured cerebral aneurysm generally includes restoring deteriorating respiration and reducing intracranial pressure. Surgery is usually performed within the first 3 days to clip the ruptured aneurysm and to reduce the risk of rebleeding. When aneurysms are discovered before rupture occurs, microcoil thrombosis or balloon embolization may be performed on patients for whom surgery is considered too risky.

The prognosis for a patient with a ruptured cerebral aneurysm depends on the extent and location of the aneurysm, the person's age, general health, and neurological condition. Early diagnosis and treatment are important.

Prepared by the National Institutes of Health