Most Brain Aneurysms Don’t Cause Symptoms

You could be walking around with an unruptured brain aneurysm. But don’t panic – the Brain Aneurysm Foundation estimates that about 1 in 50 people in the U.S. has an unruptured brain aneurysm. Director of Endovascular Neurosurgery Koji Ebersole, MD, says people are surprised to learn that the majority of aneurysms don’t cause any symptoms.

An aneurysm develops when a vessel in the brain has a thin spot, which then fills with blood, creating a bulge or balloon shape. Most brain aneurysms are small, about the size of a pea. Because the brain itself has no sensory fibers, there is no pain and the brain doesn’t register that the aneurysm is there.

“Most patients find out they have an aneurysm for a completely unrelated reason,” Dr. Ebersole says. “Maybe they’re having trouble with their sinuses and have a CT scan and the doctors find an aneurysm. When you learn you have an aneurysm, it’s important to meet with a physician who’s practiced in neurology to talk about the implications.”

The reason people are so afraid of aneurysms, says Dr. Ebersole, is because if an aneurysm does burst, it causes a dramatic health event. A very small percentage of people with an aneurysm experience a rupture that causes sudden bleeding on the brain with no warning. If the rupture spills a small amount of blood, it is an emergency but you should have time to make it to a hospital that has the expertise to treat the rupture.

A question that often arises when discussing brain aneurysms is about headaches. “People should not worry that a chronic headache is related to aneurysm,” says Dr. Ebersole.

Dr. Ebersole explains that “if you get a headache from the aneurysm, it is a very unnatural type of headache – it will be the sudden onset of the worst headache you’ve ever had in your life.” This type of headache is called a thunderclap headache because it comes on so suddenly. "The pain is caused by the blood escaping into the skull and putting pressure on the lining of the brain and that lining is incredibly sensitive.”

“In the field of aneurysm specifically, there’s been a remarkable change,” says neuroradiologist Alan Reeves, MD. “The amount of effort medical experts have put into developing microtools has skyrocketed, transforming our ability to treat the unruptured aneurysm.”

The vast majority of aneurysms do not cause trouble and do not need treatment; however, they do need to be observed by a neurologist. Most people diagnosed with an aneurysm are going to live their lives without experiencing a major health event or any trouble caused by the aneurysm.

“Advances over the past 6-8 years have completely altered our ability to treat the unruptured aneurysm, the one discovered by accident, if you will,” says Dr. Reeves. “The advances allow us to treat more and more people safely.”