Brain aneurysm

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What is a brain aneurysm?

A brain aneurysm, also known as a cerebral aneurysm, is a type of cerebrovascular disease caused by an area of weakness on a blood vessel. It occurs when the wall of a blood vessel in your brain becomes weak and bulges. The pressure inside the blood vessel causes that weak area to balloon out. If the weakened area ruptures, it can cause a hemorrhagic stroke that can lead to brain damage or even death. Most aneurysms happen in arteries, the blood vessels that carry blood to your tissues.

Types of brain aneurysms include: 

  • Berry or saccular: This is most common type. It looks like a rounded sac off the side of the artery. 
  • Fusiform: This type of aneurysm bulges out on all sides of the artery. 
  • Mycotic aneurysm: This is a rare type of saccular aneurysm caused by an infection in the artery wall. 

Brain aneurysms are relatively common, affecting about three percent of people. About one in 1000 people with a cerebral aneurysm experience a hemorrhagic stroke. If hemorrhagic stroke occurs, the risk of death is about 40 percent.

Our specialists in neurology and cerebrovascular surgery have deep experience in the diagnosis and treatment of brain aneurysms. We provide individualized care and advanced treatments to reduce your risk of stroke. 

Brain aneurysm symptoms

Symptoms vary depending on the condition of the aneurysm (unruptured, ruptured or leaking). A ruptured aneurysm is a medical emergency. Call 911 immediately.

What causes brain aneurysms?

Brain aneurysm causes typically involve any disease or condition that weakens or damages the wall of a blood vessel in the brain.

Some people are born with diseases associated with brain aneurysms, such as:

  • Arteriovenous malformations (AVM), which are abnormal connections between the arteries and veins that are prone to rupture 
  • Connective tissue disorders, such as Ehlers-Danlos syndrome, that can weaken artery walls 
  • Polycystic kidney disease (PKD), which causes cysts to form in the kidneys and other organs 

Other factors that increase your risk brain aneurysm include: 

  • Atherosclerosis
  • Alcohol abuse
  • Brain tumor
  • Cigarette smoking
  • Cocaine or amphetamine use 
  • Family history of aneurysms
  • Head trauma
  • High blood pressure
  • Infection in the artery wall (mycotic aneurysm) 
  • Intravenous drug use (mycotic aneurysm) 
  • Over 40 years of age

Brain aneurysm diagnosis

Most people don’t know they have a cerebral aneurysm until it ruptures. Doctors often find brain aneurysms during imaging tests they order for another reason.

If you have symptoms, a family history or other risk factors, your doctor may recommend brain aneurysm screening. Tests doctors use to diagnose brain aneurysms include: 

CT scan
A CT scan helps diagnose traumatic injuries, cancer, vascular diseases, and many other conditions.
MRI
An MRI provides high-resolution images of the brain, spine, and many other structures in the body.
Lumbar puncture
This test collects and analyzes cerebrospinal fluid to diagnose certain health conditions.
Cerebral Angiogram
Cerebral Angiogram
Magnetic Resonance Angiogram
Magnetic Resonance Angiogram
Computed Tomography Angiography
Computed Tomography Angiography

Brain aneurysm treatment at Penn Medicine

Treatment for a cerebral aneurysm depends on the size and location of the aneurysm and whether it has ruptured. Your age, overall health and medical history may also affect the treatment you receive. 

For small, unruptured aneurysms, your cerebrovascular expert may recommend a “watch and wait” approach. You’ll need routine check-ups to monitor the growth of the aneurysm and any underlying health conditions. You should also stop smoking and control you blood pressure to reduce the risk of rupture. 

 Larger unruptured or ruptured brain aneurysms usually require treatment. Your treatment may include a minimally invasive or surgical procedure: 

Aneurysm clipping
Aneurysm clipping is a procedure in which a surgical clip is used to close off an aneurysm.
Endovascular Embolization
Endovascular Embolization
Endovascular Procedure
Endovascular Procedure

Neurorehabilitation

If you suffer a hemorrhagic stroke, you may need therapy to regain lost function. Penn Medicine offers comprehensive neurorehabilitation services to assist with recovery after a stroke. The goals of neurorehabilitation are to: 

  • Improve speech, mobility and strength 
  • Increase the skills you need to participate in daily activities 

Related specialties

Neurosurgery
Our neurosurgeons are leaders in developing and bringing the latest treatment options to every patient.
Cerebrovascular disease care
We provide unmatched expertise, delivering exceptional and dedicated cerebrovascular disease care.

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Find a doctorCall 800-789-7366