How Dangerous Brain Aneurysm Is: Causes, Signs And Symptoms

A cerebral aneurysm is a bulging or ‘ballooning’ in the wall of a blood vessel in the brain. Some brain aneurysms are very small and do not cause any symptoms or problems; however, some have a potential to rupture or grow over time and become problematic as they grow larger.

In certain locations, when an aneurysm grows, it can press on nerves and a patient might have the following symptoms and signs:

Pain above or behind the eye
A dilated pupil
Double vision or other vision problems
A droopy eyelid
Numbness/loss of feeling in the face or one side of the body

Even worse, if an aneurysm grows, it can rupture and lead to bleeding in the brain called subarachnoid hemorrhage. 

Some of the stroke-like symptoms include:

Severe headache
Loss of consciousness

According to the Brain Aneurysm Foundation, around 6 million people in the United States have an unruptured brain aneurysm. That is about 1 in 50 people. Conversely, about 30,000 people in the United States suffer a brain aneurysm rupture every year.

A burst aneurysm is an extremely dangerous condition and requires immediate medical attention. It can be fatal in about 40 percent of cases. Of those who survive, about 66 percent suffer some permanent neurological damage.

If the aneurysm ruptures and blood spills into the space around your brain, you could have what you'd consider the worst headache of your life.

“Some patients describe it as being hit in the back of a head by a sledgehammer,” Bain says. Other symptoms include those that Mureddu experienced: nausea, vomiting, and sudden blurred or double vision, as well as a stiff neck, dizziness, sensitivity to light, and drooping eyelids. You also could have a stroke, notes the National Heart, Lung, and Blood Institute.

If the aneurysm doesn't rupture, your doctor may recommend treatment or careful monitoring. Once it ruptures, it should be treated with either open surgery or endovascular surgery, which is done within the blood vessels.

“We’ve taken a page out of the heart doctor’s book,” Bain says. In some cases, a surgeon can thread a catheter through the femoral artery to the brain and place coils to seal off the aneurysm.

Once you’ve had a brain aneurysm, you have a 10 to 15 percent chance of having another one, according to the Brain Aneurysm Foundation, and Bain says this is more likely if you’re younger than 50. “Elderly patients typically don’t get another," he says. In addition, if you smoke and have an aneurysm, it’s more likely to rupture, Bain says.