What is a Brain Aneurysm? | UI Health
Archived: 2026-04-23 17:21
What is a Brain Aneurysm? | UI Health
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Brain Aneurysm
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What is a Brain Aneurysm?
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Brain Aneurysm
What is a Brain Aneurysm?
Brain Aneurysm Risk Factors & Symptoms
Diagnosing a Brain Aneurysm
Brain Aneurysm Treatment
Brain Aneurysm Research
Brain Aneurysm Patient Stories
Contact Us
What is a Brain Aneurysm?
A brain aneurysm is a bulge or ballooning in a blood vessel in the brain. Brain aneurysms — also called cerebral aneurysm or intracranial aneurysm — form within the wall of an artery in the brain due to a weakness in the blood vessel. Over time, the weak area becomes thinner and bulges out due to blood flowing and pounding against the vessel wall. As time passes and the bulging artery becomes thinner, the aneurysm can rupture, causing bleeding into the brain.
Stroke & Aneurysm Care at UI Health
Learn about the different kinds of stroke and the relationship between hemorrhagic strokes and ruptured aneurysms with UI Health’s head of Neurosurgery, Dr. Fady Charbel.
Types of Brain Aneurysms
There are two types of aneurysms that can occur in the brain:
Saccular Aneurysm:
The most common type of aneurysm, this is also called a “berry aneurysm” because of its shape. A saccular aneurysm looks like a sac or berry that forms most commonly at an intersection, or “Y,” in the network of arteries located in the base of the brain (also called the circle of Willis).
Fusiform Aneurysm:
A less common type of aneurysm, a fusiform aneurysm looks like a widening of the entire arterial wall in the area of weakness.
Unruptured Aneurysms & Ruptured Aneurysms
Most brain aneurysms form without any symptoms. An unruptured brain aneurysm may be found during brain imaging — such as an MRI — when a patient is being screened for another condition. If an aneurysm is discovered, it's important to see a neurosurgeon who is an expert in
diagnosing,
managing, and
treating
brain aneurysms. Certain people may be at a higher
risk for brain aneurysm
. If you discover that you are at a high risk, it's important to discuss
screening tests
with your doctor.
A ruptured brain aneurysm is a serious condition and requires immediate medical attention.
Symptoms
of a ruptured aneurysm most often include sudden onset of a severe headache, most patients describe as the worst headache they have felt in their life.
Brain Aneurysm Facts
An estimated 6 million people in the United States have an unruptured brain aneurysm — one in 50 people.
Brain aneurysms are more common in women than men — 3:2 ratio.
About 10–15% of patients diagnosed with a brain aneurysm will have more than one aneurysm.
Brain aneurysms occur most commonly in adults aged 35–60, but also can occur in children. Most aneurysms develop after age 40 and have no symptoms.
Early and accurate
diagnosis
and
treatment
are critical to assuring good patient outcomes and survival.
If you are at
risk
for a brain aneurysm
, please
contact us
to schedule an evaluation today.
Find a Doctor
Request an Appointment
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Contact Us
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866.600.CARE (2273)
University of Illinois Hospital
1740 West Taylor Street
Chicago, IL 60612
© 2026 University of Illinois Hospital & Health Sciences System
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Skip to Content
ES
866.600.CARE
Find a Doctor
Request an Appointment
Locations
MyChart
Billing & Pricing
Contact Us
Español
866.600.CARE
Call Us 866.600.CARE
Primary & Specialty Care
Patients & Visitors
Referring Physicians
About UI Health
Find a Doctor
Request an Appointment
Locations
MyChart
Pay A Bill
Contact Us
Primary & Specialty Care
At UI Health, our foundation in academic excellence leads to new possibilities in healthcare. We take pride in serving Chicago and are committed to keeping your family healthy.
Find a Doctor
Make An Appointment
Locations
MyChart
Billing & Pricing
Contact Us
Call Us
866.600.CARE
For Patients & Visitors
A visit to the hospital can be overwhelming. At UI Health, we strive to make the patient and visitor experience as stress-free and comfortable as possible.
Find a Doctor
Make An Appointment
Locations
MyChart
Billing & Pricing
Contact Us
Call Us
866.600.CARE
For Referring Physicians
About UI Health
The University of Illinois Hospital and Clinics is a patient-centered organization. Providing safe, high-quality and cost-effective care for our patients is our foremost responsibility. The care of our patients and their families will always be at the heart of our mission.
Our Mission
Find a Doctor
Make An Appointment
Locations
MyChart
Billing & Pricing
Contact Us
Call Us
866.600.CARE
Brain Aneurysm
Additional
Navigation
Home
/
Primary & Specialty Care
/
Neurology and Neurosurgery
/
Neurological Conditions We Treat
/
Brain Aneurysm
/
What is a Brain Aneurysm?
Brain Aneurysm
What is a Brain Aneurysm?
Brain Aneurysm Risk Factors & Symptoms
Diagnosing a Brain Aneurysm
Brain Aneurysm Treatment
Brain Aneurysm Research
Brain Aneurysm Patient Stories
Contact Us
What is a Brain Aneurysm?
A brain aneurysm is a bulge or ballooning in a blood vessel in the brain. Brain aneurysms — also called cerebral aneurysm or intracranial aneurysm — form within the wall of an artery in the brain due to a weakness in the blood vessel. Over time, the weak area becomes thinner and bulges out due to blood flowing and pounding against the vessel wall. As time passes and the bulging artery becomes thinner, the aneurysm can rupture, causing bleeding into the brain.
Stroke & Aneurysm Care at UI Health
Learn about the different kinds of stroke and the relationship between hemorrhagic strokes and ruptured aneurysms with UI Health’s head of Neurosurgery, Dr. Fady Charbel.
Types of Brain Aneurysms
There are two types of aneurysms that can occur in the brain:
Saccular Aneurysm:
The most common type of aneurysm, this is also called a “berry aneurysm” because of its shape. A saccular aneurysm looks like a sac or berry that forms most commonly at an intersection, or “Y,” in the network of arteries located in the base of the brain (also called the circle of Willis).
Fusiform Aneurysm:
A less common type of aneurysm, a fusiform aneurysm looks like a widening of the entire arterial wall in the area of weakness.
Unruptured Aneurysms & Ruptured Aneurysms
Most brain aneurysms form without any symptoms. An unruptured brain aneurysm may be found during brain imaging — such as an MRI — when a patient is being screened for another condition. If an aneurysm is discovered, it's important to see a neurosurgeon who is an expert in
diagnosing,
managing, and
treating
brain aneurysms. Certain people may be at a higher
risk for brain aneurysm
. If you discover that you are at a high risk, it's important to discuss
screening tests
with your doctor.
A ruptured brain aneurysm is a serious condition and requires immediate medical attention.
Symptoms
of a ruptured aneurysm most often include sudden onset of a severe headache, most patients describe as the worst headache they have felt in their life.
Brain Aneurysm Facts
An estimated 6 million people in the United States have an unruptured brain aneurysm — one in 50 people.
Brain aneurysms are more common in women than men — 3:2 ratio.
About 10–15% of patients diagnosed with a brain aneurysm will have more than one aneurysm.
Brain aneurysms occur most commonly in adults aged 35–60, but also can occur in children. Most aneurysms develop after age 40 and have no symptoms.
Early and accurate
diagnosis
and
treatment
are critical to assuring good patient outcomes and survival.
If you are at
risk
for a brain aneurysm
, please
contact us
to schedule an evaluation today.
Find a Doctor
Request an Appointment
Locations
Contact Us
Accessible Care
Privacy Policy
MyChart (Patient Portal)
Accepted Insurance Plans
Price Transparency
Pay a Bill
Give a Gift
Career Opportunities
Employee Intranet
Marketing Toolkit
UIC.edu
Website Feedback
Site Map
GENERAL INFORMATION
866.600.CARE (2273)
University of Illinois Hospital
1740 West Taylor Street
Chicago, IL 60612
© 2026 University of Illinois Hospital & Health Sciences System
Find a Doc
Schedule
Locations
MyChart
Contact Us