Cerebral Aneurysm

None — Cerebral Aneurysm

An aneurysm is a weak spot along the wall of an artery feeding the brain. As blood flows through the artery, pressure can cause the weakened area to bulge out. The greatest risk with an aneurysm is rupture of the fragile wall, causing massive bleeding, and in many cases, death.

Aneurysms are classified by size. A small aneurysm is less than 11 millimeters. A large aneurysm is 11 to 25 millimeters and a giant aneurysm is one that is larger than 25 millimeters.

According to the Brain Aneurysm Foundation, about 6 million Americans have an unruptured brain aneurysm. Roughly 10 to 15 percent of them have more than one. Risk is higher among women, people over 40, smokers, and patients with high blood pressure, head injury, polycystic kidney disease, history of drug abuse and family history of cerebral aneurysms.

Most aneurysms are small and are not likely to rupture. Still, the Brain Aneurysm Foundation reports a rupture occurs in up to 27,000 Americans each year. Signs can include a severe, sudden headache, nausea and vomiting, stiff neck, vision problems, sensitivity to light, confusion, seizures or loss of consciousness. About 40 percent of those who experience a ruptured brain aneurysm die. Of those who survive, two-thirds will have some kind of permanent neurological problem. Risk for rupture is highest among those who smoke and/or have high blood pressure.

Treating Brain Aneurysms

Unruptured brain aneurysms often don't cause any problems, so patients typically are unaware they have a potentially life-threatening condition. In fact, Michael Alexander, M.D., Endovascular Neurosurgeon at Cedars-Sinai Medical Center in Los Angeles, says many brain aneurysms are detected incidentally, when patients have imaging scans for an unrelated problem.

If an unruptured aneurysm is detected, doctors can take one of two approaches – watch-and-wait or intervention. The watch-and-wait approach is usually appropriate for patients with small aneurysms or those who are very elderly or ill. If later brain scans show the aneurysm is growing, the patient may be referred for intervention. In the meantime, doctors advise patients to stop smoking, keep blood pressure under control and avoid drinking too much alcohol.

If intervention is deemed necessary, doctors have two main treatment options. One approach is clipping. In this procedure, an incision is made into the head and a portion of the skull bone is removed to access the target area of the brain. The aneurysm is located and a tiny clip is placed over the neck. The clip closes off blood flow to the aneurysm, taking the pressure off the weakened walls preventing rupture and bleeding. Over time, the aneurysm will shrink and turn into scar tissue.

A second option for a cerebral aneurysm is coiling. A catheter is inserted into an artery in the groin and fed up to the brain. When the tip reaches the aneurysm, thin platinum coils are threaded inside the sac, filling it up like a ball of yarn. If the neck of the aneurysm is wide, a stent (wire mesh scaffold) is placed in the opening to hold the coils inside. The wire is then detached and the catheter is withdrawn. The coils reduce the risk of rupture by preventing blood from entering the aneurysm.

Family Screening

Aneurysms sometimes run in families. In familial intracranial aneurysms, aneurysms are found in two or more first- and second-degree relatives. These patients are more likely to have multiple aneurysms. In addition, they are more likely to experience a rupture with smaller aneurysms than those without a family history.

Since family history is associated with increased risk for both aneurysm and rupture, relatives may want to know if they should be screened for the condition. Experts say if only one relative is affected and immediate relatives have no other risk factors, screening isn't recommended.

However, if brain aneurysm has been detected in two or more close relatives, screening is recommended. In these cases, the Brain Aneurysm Foundation recommends screening for first degree relatives every five to 10 years, starting around 25. Alexander adds that patients who have one affected family member AND a family history of polycystic kidney disease or other condition, should also be screened.

There are two main tests to screen for cerebral aneurysms. The first is magnetic resonance angiography (MRA). A special contrast material is injected into the blood vessels. Then the patient is placed in an MRI scanner. The scanner uses magnetic pulses to create images of the brain's blood vessels, enabling doctors to look for abnormalities (like an aneurysm).

The second screening test is computed tomography with angiography (CTA). An X-ray dye is injected into the blood vessels. Then, a series of X-rays are taken. The dye enables doctors to clearly visualize the cerebral arteries. CTA provides better quality images than MRA, but since it exposes the patient to radiation, it is typically not used as the initial screening tool.

Patients who are screened and found to have aneurysms should have a thorough evaluation of their risk and be informed of treatment options. Alexander says it's better to intervene before an aneurysm bursts since a rupture can have devastating or deadly consequences.

For information on brain aneurysms, screening or treatment: American Association of Neurological Surgeons Brain Aneurysm Foundation National Institute of Neurological Disorders and Stroke

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