An aneurysm is a bulging weak point in an artery.

Aneurysms most commonly occur in the arteries of the brain or in the body's largest artery, the aorta.

An aortic aneurysm can be in the chest (a thoracic aortic aneurysm or TAA) or in the abdomen (an abdominal aortic aneurysm or AAA).

Most people with an aneurysm don't even know they have one.

However, if the aneurysm grows large enough, the artery wall may become so thin that blood begins to leak into the wall of the blood vessel (called a dissection) or out into neighboring tissues or parts of the body.

An aneurysm can become so weak that it eventually bursts.

If a brain aneurysm leaks or ruptures, areas of the brain may not get sufficient blood circulation.

When the brain is deprived of blood (and therefore oxygen), a stroke results.

In other cases, an accumulation of blood from a leaking brain aneurysm may press on areas of the brain, causing brain damage.

When an aortic aneurysm leaks or ruptures, severe bleeding (called hemorrhage) may occur. This is a medical emergency that requires immediate attention.

Who Has Aneurysms?

In the United States, brain aneurysms occur in one out of every 50 people, though most of them will never have any symptoms or problems as a result.

About 27,000 people a year have a stroke caused by a burst brain aneurysm, and about 14,000 people die every year from aortic aneurysms — 75 percent of them from AAA.

Women between age 30 and 60 are most at risk for brain aneurysms, and men over the age of 65 are most at risk for aortic aneurysms.

Other groups who have a high risk of developing an aneurysm include people who:

  • Smoke
  • Have a family history of aneurysm
  • Have high blood pressure
  • Have atherosclerosis (blocked and weakened blood vessels)
  • Have Marfan syndrome (a connective tissue disorder)
  • Have untreated syphilis
  • Have infections
  • Have injuries

Signs of an Aneurysm

Sometimes a very large aneurysm may put pressure on neighboring nerves or tissues, causing pain, numbness, or other dysfunction.

However, most aneurysms cause no symptoms unless they begin to bleed or burst.

Symptoms of a dissecting or bleeding aneurysm depend on the aneurysm's location.

Symptoms may include intense pain (such as severe headache, throbbing or sharp pain in abdomen, chest and/or back), sweating, nausea, vomiting, and loss of consciousness.

Diagnosing Aneurysms

Many aneurysms are diagnosed incidentally when a patient undergoes a test for another reason.

Tests to confirm a diagnosis of aneurysm may include x-ray, ultrasound, CT scan, MRI scan, and dye studies to view the arteries.

Treating Aneurysms

Smaller aneurysms might not need treatment, just regular monitoring to make sure they aren't growing.

Some people can be treated with medicines that lower blood pressure and relax the arteries, decreasing the chance that the aneurysm will burst.

A brain aneurysm may be treated by sliding a tiny coil or clip into the area of the aneurysm, to prevent blood from reaching and enlarging it.

Larger aortic aneurysms or those that have already begun bleeding into the artery wall may need to be treated with an operation.

Surgery may be performed through an open incision or by sliding instruments through the blood vessels towards the aneurysm.