American Medical Association Family Medical Guide - American Medical Association [354]
The main risk of an aneurysm is that it might rupture and cause severe internal bleeding, depriving tissues and organs of oxygen and vital nutrients. If the bleeding significantly reduces the volume of blood in the body, the entire circulatory system could stop functioning. Without immediate medical help, a ruptured aneurysm in the aorta is usually fatal.
Three Types of Aneurysms
Fusiform aneurysm
A fusiform aneurysm forms when the artery wall is weakened all the way around the artery, like a spindle. This type of aneurysm is more common than saccular or dissecting aneurysms.
Saccular aneurysm
A saccular aneurysm develops when part of the muscular middle layer of an artery wall is damaged. This type of aneurysm occurs most often in men and in people with close relatives who have had an aneurysm.
Dissecting aneurysm
High blood pressure may cause the inner and outer layers of an artery wall to split apart. Blood is then forced between the layers, causing the outer wall to stretch. Blood trapped between the layers tends to form clots, which may fill the aneurysm and seal it off. This dissected aneurysm can then become chronic without causing any problems. However, there is a risk that the aneurysm will grow or rupture.
An aneurysm that does not rupture can disturb blood flow, creating turbulence that can lead to the formation of a thrombus (blood clot). Tiny pieces of a thrombus (called emboli) can break away and travel through the bloodstream, blocking smaller arteries and damaging tissues and organs. An aneurysm that forms in the ascending aorta may stretch the aortic valve in the heart, causing aortic insufficiency (see page 593). Aneurysms can also grow and press on and damage nearby organs, nerves, blood vessels, and other tissues.
Risk Factors
Because atherosclerosis (see page 557) and high blood pressure (see page 574) damage artery walls, people who have these conditions have an increased risk of developing aneurysms. Following a healthy lifestyle—including eating a low-fat diet, exercising regularly, not smoking, and managing stress—and taking cholesterol-lowering drugs or antihypertensive medications can help prevent or slow the progression of atherosclerosis and help keep blood pressure under control, thereby decreasing the risk of aneurysms.
Symptoms
Symptoms of aortic aneurysms depend on the type of aneurysm, the section of the aorta affected, and the structures the aneurysm presses on. Saccular or fusiform aneurysms usually do not cause symptoms. However, if a large aneurysm forms in the thoracic aorta (the portion of the aorta that passes through the chest), it may cause chest pain, back pain, hoarseness, shortness of breath, difficulty swallowing, or a persistent cough. A dissecting aneurysm in the thoracic aorta usually causes severe chest pain and shortness of breath, and may be mistaken for a heart attack.
A large saccular or fusiform aneurysm in the abdominal aorta (the portion of the aorta that passes through the abdomen) is often visible as a pulsating lump on the surface of the abdomen. If the aneurysm is toward the back, it may press on the spine and cause severe backache, especially if the aneurysm expands or ruptures. Dissecting aneurysms of the abdominal aorta are rare. When they develop, the main symptom is severe abdominal or intestinal pain.
Although aneurysms in the peripheral arteries of the arms and legs are not common and are not considered dangerous, an aneurysm that forms in the artery behind the knee can suddenly clot, blocking blood flow and causing gangrene (see page 601) of the leg.
If you have symptoms of an aortic aneurysm or if you notice an unexplainable lump anywhere on your body, especially on your abdomen, and particularly if it throbs, see your doctor right away. Most people who have a ruptured aneurysm die before they can get emergency medical treatment.
Diagnosis
Aneurysms are often detected during a routine physical examination or when a person has an ultrasound (see page 111), a CT scan (see page 112), an MRI (see page 113), or