aneurysm , localized dilatation of a blood vessel, particularly an artery , or the heart . Dilatation of an artery, and therefore weakness of that portion of the arterial wall, may be rarely congenital, or it may be caused by syphilis , hypertension (high blood pressure), arteriosclerosis , bacterial and fungal infections, or penetrating injury as from a bullet or knife. An aneurysm may be asymptomatic or it may cause varying symptoms, depending upon its location and size and on whether the expanding mass is pressing on adjacent nerves or vital organs. The weakened arterial walls of an aneurysm are always in danger of sudden rupture, with resulting hemorrhage and death.

Aneurysms occur most commonly in the large arteries; the aorta , the largest vessel in the body, is the one most often affected. Ventricular aneurysms of the heart often occur after myocardial infarctions . Aneurysms also occur in the arteries within the skull and in other areas of the body.

Aneurysms can be detected by echocardiogram, spin echo magnetic resonance imaging scans, coronary arteriograms, and biplane ventriculograms. Treatment, where feasible, may involve surgery to remove the aneurysm or the insertion of coiled wire to close it off. Coiled wire can only be used on aneurysms that are connected to the blood vessel by a narrowed neck. The coiling fills the aneurysm, obstructing the flow of blood into the dilatation, and blood clots form around the wire, preventing the aneurysm from bursting. Surgical excision of the dilated saclike portion of the affected artery sometimes requires the replacement of that portion by a synthetic graft, a section of vessel (made of polymer fiber) that is similar in size.

aneurysm (an-yoor-izm) n. an abnormal balloon-like swelling in the wall of an artery, due to disease or congenital deficiency. aortic a. an aneurysm that most frequently occurs in the abdominal aorta, below the level of the renal arteries (abdominal aortic a., AAA). Beyond a certain size it is prone to rupture: an acute surgical emergency. arteriovenous a. a direct communication between an artery and vein, without an intervening capillary bed. berry a. a small saccular aneurysm commonly affecting branches of the circle of Willis in the brain. Usually associated with congenital weakness of the vessels, they are a cause of cerebral haemorrhage in young adults. Charcot-Bouchard a. a small aneurysm found within the brain of elderly and hypertensive subjects. Such aneurysms may rupture, causing cerebral haemorrhage. dissecting a. a condition in which a tear occurs in the lining of (usually) the first part of the aorta, which allows blood to enter the wall and track along (dissect) the muscular coat. A dissecting aneurysm may rupture or it may compress the blood vessels arising from the aorta and produce infarction (localized necrosis) in the organs they supply. ventricular a. a condition that may develop in the wall of the left ventricle after myocardial infarction. Heart failure may result or thrombosis within the aneurysm may act as a source of embolism.
—aneurysmal adj.

Aneurysm

Why Are Aneurysms Called “Silent Killers”?

How Do Aneurysms Happen?

How Do Doctors Diagnose and Treat Aneurysms?

How Are Aneuryms Prevented?

Resources

An aneurysm (AN-you-rizm) is an abnormal widening of a blood vessel that may cause massive bleeding, shock, or death if it ruptures (breaks open).

KEYWORDS

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Cardiovascular system

Cerebrovascular system

Circulatory system

Why Are Aneurysms Called “Silent Killers”?

Aneurysms are sometimes called “silent killers” because they may go undetected for years until they break open. The wall of a section of an artery*, vein*, or other blood vessel may become weak and begin to bulge, like an underinflated balloon whose air is squeezed from the ends to the middle. The bulge may grow slowly for years until one day the blood vessel wall gives way. When this happens, it becomes a medical emergency that may lead to death.

* artery

An artery is a vessel that carries blood from the heart to tissues in the body.

* vein

A vein is a vessel that carries blood to the heart. Veins have greater capacity and thinner walls than arteries and contain valves that prevent blood from flowing backward and away from the heart.

Aneurysms occur most often in the aorta, the large artery that runs from the heart down through the abdomen. More than 15,000 people a year die when an aneurysm in this area breaks. Aneurysms can occur in other parts of the chest and body. When they occur in the brain, they may lead to stroke*.

* stroke

A stroke occurs when a blood vessel bringing oxygen and nutrients to the brain bursts or becomes clogged by a blood clot or other particle. As a result nerve cells in the affected area of the brain, and in the specific body parts they control, do not function properly.

How Do Aneurysms Happen?

Aneurysms result when the normal structure of blood vessels becomes weak in one area. This can occur when fatty deposits of cholesterol accumulate on the walls of the blood vessels but also may result from infection or from trauma or be congenital*. An increased incidence of aneurysm may be seen with certain conditions, such as syphilis or Marfan syndrome. Many times, however, an aneurysm develops without any known cause.

* congenital

means present at birth.

The condition affects many more men than women. It also occurs more often in people who are older than age 55, who are smokers, or who have high blood pressure. People with other family members who have had aneurysms are more likely to develop aneurysms themselves.

There usually are no signs of a growing aneurysm. Sometimes, people feel pain in their abdomen, if that is where the aneurysm is. A large aneurysm in the abdomen may press against the spine and cause back pain. A burst aneurysm in an artery can kill a person quickly. One in the brain can cause symptoms of a stroke, like shock, numbness, paralysis, and vision loss.

Monster of a Headache

R.E.M. was rocking their way through Europe during their 1995 “Monster” Tour when drummer Bill Berry got a sudden, terrible headache and could not see. Berry had a brain aneurysm, which was operated on immediately. The surgery was a complete success, and the band was able to finish touring with their excellent drummer.

How Do Doctors Diagnose and Treat Aneurysms?

Fortunately, many aneurysms can be detected before they burst. Doctors often are able to feel the pulsating sensation of abdominal aneurysms through the skin. Also, aneurysms often cause subtle changes in how the heart sounds, and doctors might notice these changes when listening to the heart. The most reliable methods of checking for aneurysms are x-rays, ultrasound* exams, and other scans that give more detailed images of the body.

* ultrasound

exams or sonograms use inaudible sound waves that can be projected by special equipment to produce an image or picture of an organ or tissue. This can help doctors to diagnose an illness and determine how best to treat the patient.

Wait and see

If an aneurysm is discovered, sometimes a doctor will adopt a “wait-and-see” strategy, but often this depends on the aneurysm’s location, size, and the person’s overall health. Small aneurysms might be checked every six months or so to be sure they are not growing. Aneurysms usually grow slowly, especially if the person adopts healthy lifestyle habits, which include not smoking, controlling blood pressure, exercising, reducing weight if necessary, not drinking alcoholic beverages, and eating an appropriate diet.

Surgery

Sometimes surgery is required. One method involves removing the section that is bulging and replacing it with an artificial blood vessel. Newer techniques involve snaking a thin, flexible wire up from an artery in the leg to the aneurysm, where a tube or coils are attached to the artery’s walls on either side of the aneurysm.

How Are Aneuryms Prevented?

It is most important to catch aneurysms before they break open. More than 60 percent of people whose aneurysms burst die before they reach the hospital, and a large percentage may die during or after emergency surgery. Regular medical care, surgery, and changing lifestyles allow the vast majority of people with aneurysms to recover.

See also

Hemorrhage

Marfan Syndrome

Stroke

Resources

The U.S. National Institute of Neurological Disorders and Stroke posts a fact sheet about cerebral aneurysm at its website. http://ninds.nih.gov/healinfo/DISORDER/Aneurysm/aneurysm.htm

American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231. The American Heart Association posts information about aortic aneurysms and many other heart conditions at its website. Telephone 800-242-8721 http://www.amhrt.org

National Stroke Association, 96 Inverness Drive East, Suite I, Englewood, CO 80112-5112. The National Stroke Association website contains information about aneurysms and new surgical techniques. Telephone 800-787-6537 http://www.stroke.org

The Heart and Stroke Foundation of Canada posts a fact sheet about aneurysm at its website. http://www.hsf.ca/az/atoz-a.htm

an·eu·rysm / ˈanyəˌrizəm/ (also an·eu·rism) • n. Med. an excessive localized enlargement of an artery caused by a weakening of the artery wall. DERIVATIVES: an·eu·rys·mal / -ˌrizməl/ adj.

aneurysm Local dilatation (swelling and weakening) of the wall of a blood vessel, usually the result of atherosclerosis and hypertension; especially serious when occurring in the aorta, when rupture may prove fatal.

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