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What is a Brain Aneurysm?

A brain aneurysm (also called cerebral aneurysm or intracranial aneurysm) forms within the wall of an artery in the brain due to a weakness in the blood vessel. Over time, the weak area of the artery becomes thinner and bulges out (like a balloon) due to blood flowing and pounding against the vessel wall. Most brain aneurysms form without any symptoms.

As time passes and the bulging artery becomes thinner, the aneurysm can rupture, causing bleeding into the brain. Symptoms of a ruptured aneurysm most often include sudden onset of a severe headache — most patients describe it as the worst headache they have felt in their life.

An unruptured aneurysm also 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 unruptured brain aneurysms.

Certain people have a higher risk for brain aneurysms. 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.

Types of Brain Aneurysms

Saccular and FusiformThere 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 that looks like a widening of the entire arterial wall in the area of weakness.  

Brain Aneurysm Facts

  • An estimated 6 million people in the United States have an unruptured brain aneurysm (1 out of 50 people).
  • Brain aneurysms are more common in women than men (3:2 ratio).
  • Approximately 10–15 percent of patients diagnosed with a brain aneurysm will have more than one aneurysm.
  • Brain aneurysms occur most commonly in adults aged 35 to 60 but can also 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.
  • Approximately 15 percent of patients with a ruptured brain aneurysm (subarachnoid hemorrhage) die before the hospital. Death occurs from the rapid and severe bleeding into the brain.
  • Ruptured brain aneurysm causes death in about 40 percent of patients. Of those patients who survive, about half will have some type of permanent disability.

The experienced team of physicians at the Brain Aneurysm Center at UI Health is recognized for its expertise in diagnosing and treating brain aneurysms.

If you are at risk for a brain aneurysm, please contact us to schedule an appointment today.