Berry Aneurysms, Artery Aneurysms

by Food and Drug Administration (FDA)

(Page 2 of 2)

Before berry aneurysms rupture, some people get warning signs. Small amounts of blood may leak from the aneurysm for hours or days, causing headaches, nausea and neck stiffness. Angiograms can locate a suspected unruptured aneurysm.

Unfortunately, in more than 90 percent of cases there are no symptoms until the aneurysm bursts. Rupture results in an excruciating headache, often accompanied by nausea and vomiting. Loss of consciousness that follows may be temporary or may proceed to coma and death. Other symptoms may include personality changes, blurred vision, paralysis on one side of the body, speech impairment, seizures, and difficulty walking or talking, depending on where the rupture occurred and the amount of bleeding.

In some cases, the ruptured artery stops bleeding by itself because swollen brain tissues in the area press against the rupture or a clot forms and plugs the rupture. When a burst aneurysm is suspected, the best diagnostic tool is the computed tomography (CT) scan, which locates the clot and indicates the amount of blood spillage in the brain in 80 percent of cases. A spinal tap (lumbar puncture) will confirm the presence of blood in the cerebrospinal fluid, the watery cushion that protects the brain and spinal cord from shock. Angiograms are usually necessary to show how large and where the rupture is located, and can pinpoint other aneurysms as well.

Neurosurgeons can open the skull and repair the aneurysm, in most cases, by placing a metal clamp at its base. Ideally, this should be done within 48 hours after hemorrhage, because the rupture can start to bleed again at any time. However, when surgery is performed by experienced hands within one to two weeks after hemorrhage on patients in good neurological condition, mortality rate is 5 percent or less. Another danger with subarachnoid hemorrhage — so-called because the blood seeps into the fluid-filled area around the brain called the subarachnoid space — is that an artery near the ruptured aneurysm may constrict or go into spasm, causing another stroke. Nimodipine (Nimotop), a calcium channel-blocking agent, has been shown to decrease the severity of neurologic damage from spasm in people who have suffered a subarachnoid hemorrhage.

When a patient is very ill, surgery is postponed to allow brain swelling to go down, usually a matter of weeks. Besides bed rest, the patient awaiting surgery may be treated with drugs to reduce severe high blood pressure, corticosteroids to reduce swelling, and analgesics to relieve headache.

Unruptured aneurysms that cause pain or other symptoms by pressing on nerves in the brain should be surgically removed. If they are detected, unruptured aneurysms that cause no symptoms should also be removed if they are more than two-fifths of an inch (10 millimeters) in diameter. Sometimes the tendency to have such aneurysms is inherited.

Medical management of people with a family history of aneurysms is controversial. "If your mother and your sister and your aunt all had aneurysms, and you are one of the worried well, you might want to have some tests," says neurologist Alexander W. Dromerick Jr., M.D., Princeton University researcher and fellow of the Hospital of the University of Pennsylvania. "MRIs are being used to screen asymptomatic relatives, but nobody is quite sure how accurate they are. An MRI will pick up large aneurysms, and some of the smaller ones, but will miss some. A CT scan will pick up evidence of bleeding, but not usually an unruptured aneurysm. What we call the 'gold standard,' the test against which all other tests are measured, is the angiogram. But there's a 1 to 2 percent chance of TIAs [transient ischemic attacks, or ministrokes], stroke and death with an angiogram, and no physician wants to expose an asymptomatic patient to this risk without good reason."

About 20 percent of people initially diagnosed with one berry aneurysm are found to have at least one more. (Berry aneurysms are found in up to 4 percent of routine adult autopsies.) As in other types of aneurysms, atherosclerosis and high blood pressure, which exerts pressure on weakened areas, cause these areas to stretch like a balloon and eventually rupture. Heavy cigarette smoking and cocaine use have also been implicated in aneurysm rupture.

Peripheral Artery Aneurysms

The third most frequent type of aneurysm occurs in the large arteries that run down the leg and in back of the knee (the femoral and popliteal arteries). They chiefly affect men and usually result from atherosclerosis, only occasionally from congenital weakness of arterial walls, injuries, or bacterial infections. They can be felt as throbbing masses in the groin and behind the knee.

Behind-the-knee aneurysms rarely burst, but they may grow so large that they interfere with circulation in the lower leg. Clots may also develop suddenly in the aneurysm, cutting off the supply of blood to the lower leg and foot, possibly leading to and necessitating amputation. Such complications can usually be prevented by replacing the affected part of the artery by a (saphenous) leg vein, as in bypass surgery.

Diagnosis may be confirmed by angiograms, which give a picture of the arteries, or ultrasound, which can determine the size of the arteries. The physician will also look for abdominal aortic aneurysms in these patients, because very often patients have both.

Aneurysms in the groin rupture more frequently than those in the knee, but otherwise are subject to the same kinds of complications. Risk factors for the development of peripheral aneurysms are high blood pressure, high blood cholesterol levels, diabetes, obesity, lack of regular exercise, and the chief culprit, smoking. Since these same risk factors are implicated in heart disease and stroke, lifestyle changes to keep blood vessels healthy will have other health benefits, as well.

Tests to Diagnose Aneurysms

Angiogram — an x-ray examination of arteries, veins or heart chambers, which is obtained by injecting a radiopaque (contrasting) dye into the bloodstream to make these structures more visible.

Computed tomography (CT) scan — special x-rays used with a computer to provide cross-sectional images or "slices" of body tissues.

Magnetic resonance imaging (MRI) — a diagnostic technique that uses the response of atoms to a strong magnetic field to produce cross-sectional images of soft tissues, such as veins and arteries.

Spinal tap — puncture of the spinal cavity with a needle to extract the spinal fluid for diagnostic purposes.

Ultrasound — use of high-frequency sound waves to produce an image or photograph of an organ or tissues. Echocardiography — a diagnostic procedure that uses ultrasound waves to visualize structures within the heart.

X-ray — a photograph obtained by bombarding a target in a vacuum tube with high-velocity electrons, enabling them to penetrate solid matter and act on photographic film.

About the Author

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