Brain Aneurysm

What is an aneurysm?

The wall of an artery (blood vessel) in the brain can become weak and balloon outward. This outward pouch is called an aneurysm (ANN-your-izm). You may hear it called a cerebral (seh-REE-brul) aneurysm. An aneurysm has thin walls. It can easily leak — or rupture — into the fluid-filled space that surrounds the brain. When this occurs, it is called a subarachnoid (sub-uh-RACK-noid) hemorrhage (HEM-ir-ij). This bleeding in the brain can lead to brain damage, disability, or death.

What might cause a brain aneurysm?

  • A condition you are born with (congenital (con-JEN-it-ul) defect)
  • High blood pressure
  • Hardening of the arteries (atherosclerosis, pronounced ath-er-o-sklair-OH-sus)
  • Brain injury
  • Infection
  • Cocaine use

What are signs and symptoms of an aneurysm?

  • Severe sudden headache. This is usually described as the worst headache of the patient’s life.
  • Nausea and vomiting
  • Loss of consciousness
  • Stiff neck
  • Fever
  • Sensitivity to light

How is a brain aneurysm diagnosed?

A CT scan of the head is done to look for blood in the brain. If the CT scan does not show the problem, a lumbar puncture and angiogram are done. A lumbar puncture (also called a spinal tap) looks for blood in the fluid inside the spine. This fluid is called CFS, or cerebrospinal (ser-EE-bro-spi-nal) fluid. Blood in the fluid means there may be a subarachnoid hemorrhage.

An angiogram is done to show the exact location of the aneurysm. A catheter (thin tube) will be placed into a blood vessel in your neck. Through this, a dye will be injected into these vessels. The dye shows up on an x-ray, and if there is any bleeding, it will appear.


A person with a ruptured cerebral aneurysm needs medical attention right away. The patient may need surgery. The surgery is called a clip ligation (lie-GAY-shun). During the surgery, a metal clip is placed at the base of the aneurysm to control the bleeding and to decrease the risk of more bleeding. More bleeding can mean more brain damage.

In some cases, the surgeon will suggest a procedure that blocks the blood vessel so that blood can no longer flow through it. This procedure is called an endovascular (en-doe-VASS-kue-ler) embolization (em-bo-liz-AY-shun). Metal coils are packed into the aneurysm through a catheter that is inserted into the groin. This procedure is done by a radiologist who is specially trained in this type of procedure. The procedure will be done in the radiology department.


Aneurysms can cause other problems. These include:

  • More bleeding, sometimes called re-bleeding. The risk of the bleeding starting again is greatest within the first 24 hours after rupture of the aneurysm.
  • Swelling in the brain because of an increase in fluid (hydrocephalus, pronounced hi-dro-SEF-a-lus)
  • Narrowing of the involved blood vessel (vasospasm, pronounced VAY-zo-spaz-um) This causes a decrease in blood flow to the brain and death of nerve cells. To prevent this complication, a drug called nimodipine is used. While the patient is in the hospital, he or she will get this drug every 4 hours. This drug helps to relax the blood vessel so that it will not spasm. The risk of vasospasm is greatest between the third day and 14th day after surgery.


The recovery of a patient with a ruptured cerebral aneurysm depends on the size and location of the aneurysm. Some patients may need quite a bit of rehabilitation after the hospital stay. The health care team will discuss these issues with the patient and family.


Brain Aneurysm Foundation
Boston, MA
Phone: 617-723-3870
Fax: 617-723-8672


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