Brain Aneurysm
An illustrated guide for patients and families.
Learn about brain aneurysms, common tests, treatment options, and questions to ask your healthcare team. Read the guide online or print a copy. Bring the separate visit sheet to your appointment.
By Dr. Shailesh Male
On this page
What is a brain aneurysm?
An artery is a blood vessel that brings blood to the brain. An aneurysm is a bulge in its wall. The bulge may look like a small pouch.
The neck is the opening where the pouch joins the artery. The dome is the rounded part of the pouch.
Unruptured or ruptured: what does that mean?
Unruptured means it has not burst. Ruptured means its wall has broken and blood is leaking out.
Bleeding into the space around the brain is called subarachnoid hemorrhage. It is an emergency.
What causes it? What raises the risk?
A weak part of an artery wall can bulge out. The cause is not always clear. Smoking and high blood pressure raise the risk. Family history and some inherited conditions also matter.
Having a risk factor does not mean you will get an aneurysm.
How do doctors find it?
Your doctor asks about symptoms, when they began, your health and your family. The exam checks things such as sight, strength and speech. Symptoms alone cannot prove that you have an aneurysm. Many cause no symptoms.
Tests may include:
- CTA: a CT scan with dye that shows blood vessels.
- MRA: a type of MRI scan that shows blood vessels.
- Catheter angiogram: a doctor guides a thin tube through an artery. Dye and X-rays show the vessels in more detail.
These tests show the bulge and help doctors judge its size, shape and place. You may not need all three.
If doctors think there may be bleeding, they often start with a head CT. A scan that looks normal does not always rule out a bleed. More tests may be needed. One is a spinal tap, which checks the fluid around the brain and spinal cord for signs of blood. The choice depends on your symptoms and when they started.
What are signs it may be getting worse?
An aneurysm can grow without causing symptoms. This is one reason to keep planned scans.
New eye pain, double vision or a drooping eyelid needs urgent medical care. If these start suddenly, especially with a bad headache, call 911.
What treatments can help?
Not every unruptured aneurysm needs a procedure. Your team weighs the risk of a bleed against the risks of treatment. Its size, shape, place and any growth matter. Your health and wishes matter too.
Watching it
You may have scans over time. Work with your team to control blood pressure. If you smoke, ask for help to quit.
Clipping
Through an opening in the skull
A surgeon makes an opening in the skull. A small clip closes the neck of the pouch from the outside.
Coiling
Through an artery using a catheter (thin tube)
A doctor passes a thin tube through the blood vessels. Soft metal coils go inside the pouch to help block blood from entering it.
Stent-assisted coiling
Through an artery using a catheter (thin tube)
A doctor uses a catheter, or thin tube, through an artery. A small mesh tube, called a stent, sits in the artery across the neck. It helps hold coils inside the pouch.
Flow-diverter stent
Through an artery using a catheter (thin tube)
A doctor uses a catheter through an artery to place a special mesh tube. This tube sits in the artery across the neck. It redirects blood flow so the pouch can close over time. It does not seal the pouch right away.
These are simplified drawings, not to scale. Different options suit different aneurysms.
Treatment risks and medicines
Not every option fits every aneurysm. Procedures can cause stroke, bleeding or other harm. A burst aneurysm needs urgent hospital care.
If you have a stent, you may need drugs that help stop blood clots. Do not stop these prescribed drugs without advice from your treating team.
What is the outlook?
Many people live for years with an unruptured aneurysm. The risk is not the same for everyone. Keep the scan and care plan your team gives you, even if you feel well.
A burst aneurysm can cause death or lasting brain injury. Some people recover well. Others need help with movement, memory or daily tasks. Recovery depends on the harm from the bleed, other health problems and treatment. Scans may still be needed after a procedure.
When should I call 911?
Call for any of these:
- A sudden, very bad headache, especially if it reaches its worst within a minute.
- Sudden weakness, trouble speaking or loss of sight.
- Collapse, loss of consciousness or a new seizure.
Do not wait for all these signs. A bad headache may also come with vomiting or a stiff neck. These signs can have other causes, but they need urgent care. Do not drive yourself.
Does it run in families? Should my family get checked?
Sometimes. Family risk does not mean every relative will get an aneurysm. Screening means looking for one before there are symptoms.
Tell your doctor which relatives have had a brain aneurysm or a bleed from one. AHA/ASA guidance says screening should be offered when two or more family members have had these problems. Parents, brothers, sisters and children are especially important. Ask a specialist which relatives should be screened and when. One affected relative also deserves a discussion; it does not mean everyone needs a scan.
An inherited kidney disease called ADPKD can also raise risk. People with this disease should ask about brain-aneurysm screening, especially if they or relatives have had a brain bleed or aneurysm, or a relative died suddenly for an unknown reason. The decision also depends on health and whether treatment could help.
Questions for your visit
- Should we watch my aneurysm or treat it, and why?
- When is my next scan, and who will explain it?
- What should I know about medicines and daily activities?
- Should anyone in my family be screened?
Use the separate visit sheet available at the top of this page to write down your questions and take notes with your healthcare team.
For education only. This handout does not replace medical advice, diagnosis, or treatment from your healthcare team. Your care may be different. For an emergency, call 911.