Let’s Talk About Brain Aneurysms
A brain aneurysm is a weak, bulging spot in a blood vessel in the brain. It’s like a thin balloon or a weak spot on a tire. Because the walls of the aneurysm are thin and weak, there
is a chance it could burst (rupture).
If a brain aneurysm ruptures, it causes bleeding in the brain, which can lead to a serious type of stroke called a subarachnoid hemorrhage (SAH). This happens when blood flow is interrupted due to the bleeding. Ruptured aneurysms cause 3%-5% of all new strokes and can lead to severe brain damage or death.
Many brain aneurysms are treatable, so it is important to know the warning signs and risk factors. Early detection is critical.
What are the risk factors for a brain aneurysm?
- Smoking – Smoking can raise triglycerides, lower “good” cholesterol, damage cells that line the blood vessels, increase the buildup of plaque and cause thickening and narrowing of blood vessels. In addition, exposure to secondhand smoke interferes with the normal function of the heart, blood and vascular system. Quitting smoking and avoiding second-hand smoke can reduce this risk.
- Hypertension – Over time, high blood pressure can weaken the walls of blood vessels, raising the chances of an aneurysm forming. Keeping your blood pressure in check can lower this risk.
- Family history – If a close family member, such as a parent or sibling, has had a ruptured aneurysm, you may be at higher risk. This risk increases if multiple family members have had brain aneurysms or ruptures. Those with a family history may also experience an aneurysm rupture at younger ages and with smaller aneurysms.
- Age – While brain aneurysms can occur at any age, they are most common in adults ages 30-60. Children may be at risk of an aneurysm due to disorders such as Ehlers-Danlos syndrome or Marfan syndrome.
- Gender – Women are more likely to have brain aneurysms than men, and their risk increases after menopause.
- Drug use – The use of hard drugs such as cocaine and amphetamines can cause blood vessels to swell and raise blood pressure, both of which increase the risk of an aneurysm.
- Traumatic head injury – A head injury can damage blood vessels or stretch their walls. This is more common in children, although traumatic aneurysms are rare overall.
What are the warning signs of a brain aneurysm rupture?
- Sudden severe headache – A sudden, intense headache, often described as one of the “worst headaches of your life,” can be a sign that an aneurysm has ruptured. This requires immediate medical attention.
- Dilated pupils – One or both of your pupils may appear larger than normal.
- Blurred, sensitive or double vision – Your vision may become blurry, or you may “see double.” You may also experience increased sensitivity to light.
- Pain above and behind the eye – Any pain or weakness around your eye could be a result of an aneurysm pressing on nearby nerves.
- Weakness and numbness – You might feel weakness or numbness due to the aneurysm bursting or putting pressure on surrounding tissues and nerves.
- Difficulty speaking – Slurred speech or trouble finding the right words could be linked to an aneurysm or its rupture.
Stroke warning signs
Stroke is an emergency! Call 911 immediately if you see one or more signs of a stroke. Note the time when any symptoms first appear. Quick treatment can make the difference between life and death.
Signs and symptoms of stroke can differ depending on what part of your brain is impacted. Use the letters in F.A.S.T. to recognize several common stroke symptoms and remember what to do.
- F = Face Drooping
- A = Arm Weakness
- S = Speech Difficulty
- T = Time to Call 911
How can I learn more?
- Call 1-888-4-STROKE (1-888-478-7653) or visit stroke.org to learn more about stroke or find local support groups.
- Sign up for our monthly Stroke Connection e-news for stroke survivors and caregivers at StrokeConnection.org.
- Connect with others who have also had an experience with stroke by joining our Support Network at stroke.org/SupportNetwork.
Do you have questions for your doctor or nurse?
Take a few minutes to write down your questions for the next time you see your health care professional. For example:
What medical conditions do I have that increase my risk for a brain aneurysm?
What lifestyle factors increase my risk for having a brain aneurysm or rupture?
How can I reduce my risk for a brain aneurysm?
We have many other fact sheets to help you make healthier choices, manage your condition or care for a loved one.
Visit stroke.org/LetsTalkAboutStroke to learn more
The American Stroke Association and the Brain Aneurysm Foundation – collaborating to educate the public about brain aneurysms and strokes.
© Copyright 2025 American Heart Association, Inc., a 501(c)(3) not-for-profit. All rights reserved.
American Stroke Association is a registered trademark of the AHA. Unauthorized use prohibited. WF911626 5/25