What is a Brain Aneurysm?

When Kim Kardashian revealed that her doctors found a small brain aneurysm, the public responded with curiosity and concern. What exactly is a brain aneurysm, and how worried should you be if you have one?

A cerebral aneurysm is a bulge or ballooning in a weakened area of a blood vessel in the brain. Although they are considered relatively common, it is unclear how prevalent brain aneurysms are, because not everyone gets an imaging test to screen for them.

“The significant majority of aneurysms, at least in the United States, are found because people have an MRI [magnetic resonance imaging] or an MRA [magnetic resonance angiography] test,” says Columbia neurologist Joshua Willey, MD, who specializes in stroke and cerebrovascular neurology. “Oftentimes, our patients who have headaches, or memory loss, or other neurological symptoms come in, we do a scan, and we happen to find the aneurysm.”

Based on the most common questions he hears from patients about aneurysms, Dr. Willey explains the risks, warning signs, and preventive measures we can all take.

Can you explain the difference between an unruptured and ruptured aneurysm?

In most people, an aneurysm will never rupture, never leak, and won't cause any symptoms. The majority of people with an unruptured aneurysm will continue leading their everyday lives.

However, in a subset of individuals, an aneurysm leaks or ruptures, and that causes a significant brain bleed, which is a medical emergency. It feels to people like an explosion in their head: a severe, sudden-onset headache. You need to call 911 and get to the nearest hospital.

What are the symptoms of a brain aneurysm?

Symptoms of an unruptured aneurysm can include double vision and pain behind the eye, but in most patients, it is asymptomatic.

The most important symptom of a ruptured aneurysm is what we call a "thunderclap" headache. This is a sudden-onset, severe headache that reaches its maximum intensity within a minute. It's unlike any headache that anybody has ever experienced. This should prompt urgent medical attention.

How is a typical migraine different from a ruptured aneurysm?

The vast majority of migraines can be very intense, but they take some time—from several minutes to an hour—to reach the maximum degree of pain. Whereas the pain that people describe with an aneurysm is very different: It is intense basically right away.

So, it's like the heart attack of headaches?

Correct. I like that analogy.

What happens if an unruptured aneurysm is found on a scan?

Once an unruptured aneurysm is found, a health care provider will usually begin by recommending a yearly scan to track it and make sure it’s not rapidly growing or changing in size.

If it's rapidly changing in size, that is a reason to potentially treat it before it ruptures. If the chances of rupture are high enough, even though it hasn't caused any symptoms, we will discuss the risks and benefits of surgery.

Is it hard for people to wait and watch?

A lot of people have anxiety when an aneurysm is found. Still, the vast majority of the time, it's small enough in a specific location that I can tell them there's a 98 percent chance, if not higher, that it will never cause any problems. They usually say, "Wow, I didn't realize that." I let them know that surgery is more likely to cause harm. And they'll say, "Oh, I can live with that."

What factors put people at higher risk for a brain aneurysm?

There are two important risk factors: active tobacco use and uncontrolled blood pressure. I tell people there are things you can do to gain control and prevent an aneurysm from ever causing any problems: If you smoke, quit; If you have high blood pressure, work vigilantly with your health care team to manage it. That includes diet, exercise, measuring your blood pressure, and taking medicines as needed.

Can stress increase aneurysm risk?

Stress directly does not cause an aneurysm to form. That being said, stress can impact blood pressure, or cause people to smoke to deal with the stress.

How are strokes and aneurysms related?

An aneurysm itself, if it hasn't ruptured, is not a type of stroke. An aneurysm that bleeds is a type of stroke and needs immediate care at a comprehensive, specialized, neuro-intensive care unit, such as ours, at the Columbia University Irving Medical Center. This is extremely important.