What Does a Brain Aneurysm Feel Like?

A ruptured brain aneurysm can be life-threatening. But most brain aneurysms don’t rupture, and many people live their lives without even knowing they’re there.

“Many people actually have aneurysms, perhaps up to 5% of the general population, but they don't know it,” says Nirav J. Patel, MD, a neurosurgeon with the Mass General Brigham Neuroscience Institute. “They're normal… they're intelligent. They're living their life.”

That’s because an unruptured brain aneurysm typically has no effect on the body. “It does nothing,” says Dr. Patel. “You can still have a full and normal life.”

While the risk of rupture may be small, knowing the signs of a brain aneurysm can save lives.

What is a brain aneurysm?

An aneurysm is a bulge in a blood vessel resulting from a weak spot in the vessel wall. Aneurysms can happen anywhere in your body, including the heart, abdomen, legs, and brain.

A ruptured brain aneurysm is particularly dangerous as it allows blood to enter the space between the brain and the membrane that covers it, which is a type of stroke known as a subarachnoid hemorrhage. As the blood pools, pressure builds on the brain. This pressure can result in brain damage or death.

However, the vast majority of brain aneurysms don’t rupture. In the United States, an estimated 6.8 million people have an unruptured brain aneurysm.

Symptoms of a brain aneurysm

Most brain aneurysms are smaller than one inch. But even large brain aneurysms don’t usually cause symptoms before they rupture. Occasionally, if the aneurysm is in an artery that affects the eye, people may experience changes in their vision, a drooping eyelid, or pupil dilation. Rarely, large aneurysms may also cause numbness on one side of the face.

A ruptured brain aneurysm has a profound effect on the body. In cases where an aneurysm causes a slow leak, people may experience severe headache. Once a rupture happens, people usually experience a sudden, extremely intense headache.

“If it ruptures, what it feels like is the worst headache of life, worse than anything you've ever had, like a hammer hitting the back of the head,” says Dr. Patel.

Along with a headache, symptoms of a brain aneurysm rupture also include:

• Confusion or loss of consciousness
• Eye pain or sensitivity to light
• Nausea and vomiting
• Neck stiffness
• Seizures
• Speech impairment
• Weakness or loss of balance

If you experience any symptoms of brain aneurysm, seek medical attention right away. A ruptured aneurysm is a life-threatening emergency.

What to do if you have a brain aneurysm

Many people are diagnosed with an unruptured brain aneurysm when they have brain imaging for another reason. “It's really important for those patients to see a specialist to discern if this aneurysm should be treated or not,” says Dr. Patel. “I’d also suggest getting a second opinion to feel comfortable with this complex and potentially dangerous diagnosis.”

Your doctor may decide that your aneurysm can be monitored. You will have regular brain imaging tests to watch for changes. You’ll also be encouraged to make lifestyle changes, such as quitting smoking, to reduce the risk of rupture.

If you and your surgeon decide treatment is the best option, you’ll have an operation to stop blood flow to the aneurysm, preventing rupture.

“It’s a scary thing,” says Dr. Patel. But, “It’s okay, this is treatable. We can help you.”