Brain aneurysm

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Definition Symptoms Causes Risk factors When to seek medical advice

Tests and diagnosis Complications Treatments and drugs Prevention

Definition

A brain aneurysm is a bulge in an artery in your brain. The most common type of brain aneurysm looks like a round berry — attached to your artery by a tiny neck. As long as the aneurysm is small and doesn't rupture, it poses little risk to your health. Such aneurysms may go undetected indefinitely and produce no signs or symptoms.

But some brain aneurysms are large enough to put pressure on surrounding brain tissue. Others may rupture at a weak spot in the artery wall, flooding an area of your brain with blood. A ruptured aneurysm may quickly become life-threatening and requires prompt medical attention.

In the United States, between 2 percent and 5 percent of the population — up to 15 million people — have or will have berry-type (saccular) brain aneurysms. But fewer than 30,000 of these aneurysms rupture each year. Most aneurysms, particularly small ones, don't rupture.

People of all ages can have a brain aneurysm, but they're more common in adults than children. Women are slightly more likely to develop an aneurysm than men are. How serious an aneurysm is depends on its size and location and on your age and health. Small unruptured aneurysms are often best left alone, though treatments are available for larger aneurysms.

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Symptoms