aneurysm is a bulge in all three layers of a blood
vessel wall. If there is a bulge in some portion of the blood vessel wall but
not in all three layers (commonly seen in aneurysms formed as a result of
injury), it is a pseudoaneurysm.
The aorta could be described as a smooth tube that is fairly constant
in diameter throughout its course from the heart to the abdomen until it
divides. An aneurysm occurs when a portion of the
aorta bulges more than 3 centimeters in diameter.
After it initially forms, it is likely to increase in size as you age.
It is possible that the main title of the report Meningitis, Bacterial is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
As an aneurysm expands, the tension on the blood vessel wall
increases. This in turn causes the aneurysm to expand further, which puts even
more tension on the wall. This cycle continues, and the larger the aneurysm
gets, the greater the chances that it will grow larger and eventually burst.
Understanding that aneurysms expand is a key to managing them: the
larger they become, the higher the rate of rupture, and the more important it
is to treat them.
The location of the aneurysm is also important. Aneurysms can be
located in any blood vessel in the body. Aortic aneurysms can be found in the
thoracic portion, the abdominal portion, or both. The treatment, surgical
approach, and outcome of aneurysms involving the thorax and the abdomen can be
For example, if an abdominal aortic aneurysm is found below the
kidneys, the aorta is cross-clamped below the arteries that supply blood to the
kidneys (renal arteries), allowing a normal blood flow and a less risky
operation. On the other hand, if the aneurysm is located above the kidneys, the
clamp may have to be placed above the renal arteries and thus blood flow to the
kidneys is limited. This increases the risk for kidney failure.
Another distinction should be drawn between aneurysms based on their
cause. While most arise from chronic changes in the arterial wall and take many
years to develop, a small percentage are caused by infection or inflammation.
These are called inflammatory aneurysms. While the surgical principles are the
same for all aneurysms, inflammatory aneurysms may be more severe and
occasionally involve other blood vessels and adjacent organs.
Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
David A. Szalay, MD - Vascular Surgery
January 26, 2010
WebMD Medical Reference from Healthwise
January 26, 2010
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