An aneurysm is a permanent swelling of an artery due to a weakness in its wall. Aneurysms can form anywhere, but the most comAmon and troublesome sites are the arteries of the brain, and the aorta, the large major artery through which the heart pumps blood to the rest of the body. There are, basically, three reasons why an aneurysm might develop in one of your arteries:1. There are three layers of tissue in your arterial walls. The supportive strength of your arteries is supplied by the muscular middle layer, and this layer may be congenitally defective. The normal pressure of blood in the affected artery causes a balloon-like swelling, which is called a saccular aneurysm, to develop at that point. Aneurysms due to congenital defects are nearly always found in arteries at the base of the brain. Because of their shape and because several of them are often clustered together, they are known as "berry" aneurysms.
2. Inflammation, whatever the cause, may weaken an arterial wall. Most arterial inflammation is caused by disorders such as polyarteritis nodosa or bacterial endocarditis .
3. A portion of the muscular middle layer of an arterial wall may slowly degenerate as the result of a chronic condition such as atherosclerosis or high blood pressure . An aneurysm that is caused by atherosclerosis is likely to be a sausageAshaped swelling called a fusiform aneurysm that runs along a short length of the artery. A similar type of swelling may be caused by high blood pressure. Increased pressure of blood in an artery, however, can stretch the wall in many different ways. It can even split the layers, and force blood between them. This is called a dissecting aneurysm.
Aneurysms can cause trouble in several ways. They can burst, which leads to a loss of blood supply for certain tissues, and to hemorrhage, or internal bleeding, at the site of the aneurysm. They can swell so much that they press on and damage neighboring organs, nerves, or other blood vessels. They also can disturb the flow of blood to such an extent that its eddying and whirl pooling cause dangerous clots to form.
What are the Symptoms?
The symptoms of aneurysm vary according to the type, size, and location of the swelling. Berry aneurysms, or those at the base of the brain, usually cause no symptoms until they burst. A sudden severe headache at the back of your head, or even unconsciousness, may be the first sign of this type of aneurysm .
If you have an aneurysm of the aorta, your symptoms will depend on two factors: what section of the aorta is affected; and what type of aneurysm you have. The most common symptoms of a saccular or fusiform aneurysm in the thoracic aorta, or the portion of that artery that passes through your chest, are chest pain, hoarseness, difficulty in swallowing, and a persistent cough that is not helped by cough medicine. If you have a dissecting aneurysm in the same area of your aorta, you are likely to have pain that can easily be mistaken for a heart attack . In either case, you will not be able to see or feel the swelling on the surface of your chest, because your thoracic aorta is confined with in your rib cage.
A saccular or fusiform aneurysm in the abdominal portion of your aorta can usually be seen as a throbbing lump. Other symptoms include loss of appetite and loss of weight. If the aneurysm is located towards your back, it may press on the bones of your spine, and cause severe backache. Dissecting aneurysms of the abdominal aorta are relatively rare. When they do occur, the main symptom is severe abdominal pain. Aneurysms in other parts of the body are rare and generally of little consequence.
What are the Risks?
The major risk of an aneurysm is that it may burst, and cause a hemorrhage. A burst aneurysm allows blood to flow into the surrounding tissues, which causes serious local damage. Moreover, the entire circulatory system may collapse if the leak drastically reduces the volume of blood in the circulation. Unless expert medical help is available, a burst aneurysm in the aorta can be fatal. More than 40 per cent of all people who have a burst berry aneurysm die as a result.
Even when it does not burst, an aneurysm of the aorta causes turbulence in the flow of blood that can cause the formation of a thrombus, or clot, with all the associated dangers. Emboli, or parts of a blood clot that break away from the thrombus, can block smaller arteries such as those that supply the kidneys or other organs, and this can lead to many problems. Turbulence in the aorta also can stretch the aortic valve of the heart and cause aortic incompetence .
Aneurysms sometimes occur in more peripheral arteries, such as those of the arms and legs, but in these locations they are generally less hazardous.
What should be done?
You can do nothing about berry aneurysms, since you probably will not know that you have one unless it bursts. If you have any of the symptoms of an aneurysm of the aorta or if you inexplicably develop a lump anywhere on your body, especially on your abdomen, and particularly if it throbs, consult your physician immediately. Many of the symptoms can be caused by other, often trivial conditions, so the physician will probably want to give you a full examination before making a definite diagnosis. To find out the size, type and location of an aneurysm, if you have one, you may need to have extensive X-rays, chiefly to verify and locate the atherosclerosis that probably caused it. You may have to have arteriography and ultrasound tests to help identify the aneurysm.
What is the Treatment?
Self-help: The best ways to prevent aneurysms are to take steps to prevent or slow down atherosclerosis and to keep your high blood pressure under control . If you have already developed an aneurysm, there is no effective self-help.
Professional help: Surgery is the usual treatment for an aneurysm, but the surgeon must consider the location and size of the aneurysm and the condition of the rest of your arteries before recommending the procedure. The operation is difficult and risky.
What are the Long-Term Prospects?
About 30 per cent of people with ruptured berry aneurysms die instantly, and another15 per cent die from further bleeding within a few weeks. The outlook for long-term survival is excellent if you have a successful operation and live for six months after the first hemorrhage occurs.
Surgery for aneurysms of the thoracic aorta is often impossible, and in such cases the long-term outlook is poor. With operable chest aneurysms there is an 80 to 90 per cent chance of survival. Abdominal aneurysms are frequently a much less serious problem. In general, they need to be removed only if they are very large or if they are found to be growing. With or without surgery, the outAlook is good for most of these. The same is true for aneurysms in peripheral arteries.
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