Ingrid Rigakos, age 16, of Vancouver, Wash., for her question:
WHAT CAUSES AN ANEURYSM?
An aneurysm is a ballooned, dilated area of an artery that carries the body's blood. It can be likened to the ballooning of a weakened spot on an inner tube or tire. The hardening and loss of elasticity of the artery is the major cause of aneurysms.
Aneurysms can occur anywhere in the circulation system, but the segments of the aorta, which is the body's main artery that lie in the chest and in the abdomen, are common sites.
Aneurysms are rarely found in persons under the age of 50. Also, they are 10 times more frequent in men than women.
The structural reason for aneurysm formation is damage to the middle layer of the wall of the artery. When only the thin lining and outer fibrous layers remain, the artery begins to dilate or balloon out from the pressure of the pulsating blood flow.
In its early stages, an aneurysm will produce no symptoms. Symptoms usually develop as the aneurysm enlarges and exerts pressure on adjacent organs and tissues.
In the later stages, the aneurysm can also produce symptoms caused by thinning of the artery wall or by leaking of blood through the thin wall. The location and severity of the symptoms depend largely upon the location and the size of the aneurysm.
The most common type of aneurysms occur in the abdominal aorta. They usually start just below the level where the renal arteries branch off to supply the kidneys. The major symptom usually is pain in the upper abdomen or lower back. The pain may extend into the groin and the legs.
Pain is an important symptom, because it often indicates rapid enlargement or leaking of the aneurysm. If it is not treated, the aneurysm usually will rupture, causing intense pain and leading to death from loss of blood.
Chest aneurysms usually are discovered on an X ray taken for some other reason.
Abdominal aneurysms without symptoms are detected during a physical examination for an unrelated abdominal symptom, but if the patient is greatly overweight or if the aneurysm is small, it may not be found.
An X ray may show the aneurysm if calcium is present in the aneurysm wall. The use of ultrasound also has proved valuable. By this method, an image of the aneurysm and its size can be obtained. Not only can the diagnosis be confirmed, but the development of the aneurysm can be followed in patients who are poor risks for surgery.
When an aneurysm is large or is producing symptoms, the preferred treatment is to remove the affected portion of the artery surgically and replace it with a synthetic fabric graft.
The decision about whether smaller, symptom less aneurysms should be removed depends on the patients age and general health. Results of surgery for aneurysms are good, and surgery has been a major factor in reducing the previously high death rate caused by aneurysms that were not treated surgically.