Brain Aneurysm

• Brain Aneurysm Overview
• Brain Aneurysm Causes
• Brain Aneurysm Symptoms
• When to Seek Medical Care
• Exams and Tests
• Brain Aneurysm Treatment
• Self-Care at Home
• Medical Treatment
• Next Steps
• Follow-up
• Prevention
• Outlook
• For More Information
• Web Links
• Synonyms and Keywords
• Authors and Editors

Brain Aneurysm Overview

An aneurysm is an abnormal widening or ballooning of a portion of a blood vessel. A cerebral aneurysm refers to a blood vessel within your brain that weakens over time and undergoes such widening. This usually occurs at the junctions of the large arteries at the base of your brain, in an area called the Circle of Willis.

As the blood vessel weakens, it begins to bulge out like a balloon. Often, as an aneurysm develops, it forms a neck with an associated dome, or balloonlike structure. The larger the balloon becomes, the greater the risk it may burst. You would then bleed into your brain.

Autopsy studies have revealed that 3-6% of adults in the United States have aneurysms inside their brains. Fortunately, many of these aneurysms are small and not at risk to break. The rates of aneurysms found by accident when other studies are performed suggest that 8-10 million Americans have brain aneurysms. About 20-30% of people with an aneurysm will have more than 1. Each year, for every 100 people with an aneurysm, roughly 1 of them will suffer a rupture or break—a condition known as subarachnoid hemorrhage.

Currently no one can predict which aneurysms will rupture. Data suggest that aneurysms that rupture tend to be larger than 10 mm (0.4 in). About 25,000-30,000 cases of ruptured aneurysms occur in the US each year. About 40% of the people who suffer bleeding from an aneurysm die within the first month. Approximately another one third have residual major nervous system problems but survive.

Many are left with long-term memory problems. They may have difficulty in the following: thinking, perception, and performing simple daily activities.

People who have survived a rupture of a brain aneurysm are twice as likely as the general population to develop another aneurysm. If a second aneurysm occurs, these people are 6 times more likely to have another ruptured aneurysm and bleeding in their brain.

Brain Aneurysm Causes

Aneurysms in the brain are considered to be acquired problems. They are not present at birth. Rather, they develop over a lifetime.

Other evidence indicates that genetic factors make some people more likely to develop brain aneurysms. The exact pattern of inheritance is not clear.

• According to several studies, up to 20% of people with bleeding from an aneurysm have a first- or second-degree relative with a brain aneurysm.
  
  
• These relatives are at higher risk for bleeding in the brain.
  
  
• In most families with brain aneurysms, the condition affects only 2-3 members of the extended family, and the method of inheritance is not apparent.

Associated conditions - A number of conditions are associated with brain aneurysms, as follows:

• Polycystic kidney disease - A genetic disorder characterized by the growth of numerous cysts in the kidneys
  
  
• Ehlers-Danlos syndrome - A group of inherited connective tissue disorders characterized by extreme flexibility of joints, easily stretched skin and easily damaged tissue
  
  
• Marfan syndrome - An inherited disorder of connective tissue, the glue and the scaffolding of your body, which leads to tissue with less strength and that can rupture easier 
  
  
• Neurofibromatosis - A group of 8 genetic disorders of the nervous system that primarily affect the development and growth of nerve cell tissues (These disorders cause tumors to grow on nerves and produce other abnormalities such as skin changes and bone deformities.)

Environmental factors: Significant evidence suggests that environmental factors make some people more likely to develop brain aneurysms.

• Brain aneurysms are very rare in children.
  
  
• The likelihood of having an aneurysm increases throughout life.
  
  
• Tobacco
  
  
  • Cigarette smoking is the only factor that has been consistently demonstrated to increase the risk of ruptured aneurysm.
    
    
  • Sustaining a rupture of a brain aneurysm is about 10 times more likely in a smoker than in a nonsmoker.
    
    
  • The more cigarettes smoked, the higher the risk.
  
  
• High blood pressure
  
  
  • Several studies have shown an increased risk for the development and rupture of brain aneurysms in people with high blood pressure.
    
    
  • Most experts believe that high blood pressure remains a risk factor but not to the extent that cigarette smoking is a risk.
  
  
• High cholesterol
  
  
  • The effect of high cholesterol remains unclear.
    
    
  • Three studies have looked at high cholesterol as a risk factor for aneurysm and rupture. Two studies showed no association and one study showed a relationship.
  
  
• Alcohol consumption
  
  
  • A moderate to high level of alcohol use is considered a risk factor for the rupture of a brain aneurysm.
    
    
  • It is unclear if alcohol use increases the risk of developing an aneurysm.
    
    
  • Binge drinking appears to dramatically increase the risk of subarachnoid hemorrhage from a ruptured aneurysm.

Next: Brain Aneurysm Symptoms »

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