Overview: The phrase cerebral aneurysm refers to the bulging of a weakened area in the wall of an artery in the brain, resulting in abnormal ballooning. Because there is a weakened spot in the aneurysm wall, there is a risk for rupture (bursting) of the aneurysm. A cerebral aneurysm more frequently occurs in an artery located in the front part of the brain that supplies oxygen-rich blood to the brain tissue. Arteries anywhere in the brain can develop aneurysms. The most common type of cerebral aneurysm is called a saccular, or berry, aneurysm, so named because the deformity looks like a “berry” with a narrow stem. Fusiform and dissecting are the other two types of aneurysm—the former bulges out on all sides forming a dilated artery and are often associated with atherosclerosis. A dissecting aneurysm results from a tear along the length of the artery in the inner layer of the artery wall, causing blood to leak in between the layers of the wall. This may cause a ballooning out on one side of the artery wall, or it may block off or obstruct blood flow through the artery. Dissecting aneurysms usually occur from traumatic injury, but they can also happen spontaneously. The shape and location of the aneurysm may determine which treatment is recommended. Smaller aneurysms may have a lower risk of rupture.
It is estimated that 2% of people have one or more brain aneurysms. Most aneurysms declare themselves by bleeding in adults between the ages of 45 to 65 years. Children, however, can also present with aneurysms. The type of diagnostic testing performed depends on the location of the aneurysm. In addition to a complete medical history and physical examination, diagnostic procedures for an aneurysm may include a combination of scans including CT scans and arteriogram (see Tech & Procedures).
Ruptured brain aneurysms are treated either by surgical clipping, a procedure that closes off an aneurysm or the less invasive endovascular coiling procedure wherein a surgeon threads a hollow plastic tube (catheter) through an artery in your body to the aneurysm and uses it to disrupt the blood flow causing the blood to clot and thereby seal off the aneurysm.
The other forms of treatment aim at relieving symptoms and managing complications and involve pain relievers. Calcium channel blockers prevent calcium from entering cells of the blood vessel walls. These medications may lessen the erratic narrowing of blood vessels that may be a complication of a ruptured aneurysm.
Doctors aim to avert the possibility of a stroke owing to insufficient blood either through drugs that elevate blood pressure or a procedure called angioplasty in which a surgeon uses a catheter to inflate a tiny balloon that expands a narrowed blood vessel in the brain. A catheter may also be used to deliver appropriate drugs. To avert seizures related to ruptured aneurisms anti-seizure medications may be used. Ventricular or lumbar draining catheters and shunt surgery can lessen pressure on the brain from excess cerebrospinal fluid (hydrocephalus) associated with a ruptured aneurysm.
Treating unruptured brain aneurysms: Surgical clipping or endovascular coiling can be used to seal off an unruptured brain aneurysm and help prevent a future rupture. However, the known risks of the procedures may outweigh the potential benefit.
Computed tomography scan (CT or CAT scan): A diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than standard x-rays.
Magnetic resonance imaging (MRI): A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
Arteriogram (angiogram): An x-ray image of the blood vessels used to evaluate various conditions, such as aneurysm, stenosis (narrowing of the blood vessel), or blockages. A dye (contrast) is injected through a thin flexible tube placed in an artery. This dye makes the blood vessels visible on the x-ray.
Angioplasty: A procedure in which a surgeon inflates a balloon at the tip of a catheter and thereby expands a narrowed blood vessel in the brain and eases the flow of blood. A catheter may also be used to deliver to the brain a drug called a vasodilator, which causes blood vessels to expand.