Encyclopedia / A / Aneurysms



A localized dilation of the wall of a blood vessels, usually caused by atherosclerosis and hypertension, or less frequently, by trauma, infection, or a congenital weakness in the vessel wall.


Aneurysms are most prominent and significant in the aorta, but also occur in peripheral vessels and are fairly common in the lower extremities of older people, especially in the popliteal arteries.

A sign of an arterial aneurysm is a pulsating swelling that produces a blowing murmur on auscultation (the act of listening for sounds in the body) with a stethoscope. An aneurysm may rupture, causing hemorrhage, or thrombi may form in the dilated pouch and give rise to emboli that may obstruct smaller vessels.


Aneurysms can be congenital (people can be born with the defect) or they can occur as a result of aging or disease. The most common disease associated with aneurysms is atherosclerotic disease.


Symptoms will depend upon the location of the aneurysm. Common sites include the abdominal aortic artery, the intracranial muscles (supplying blood to the brain), and the aorta (supplying blood to the chest area).

Many aneurysms are present without symptoms and are discovered by feeling or on x-ray films during a routine examination.

When symptoms occur, they include a pulsing sensation, and there may be pain if the aneurysm is pressing on internal organs. If the aneurysm is in the chest area, for example, there may be pain in the upper back, difficulty in swallowing, coughing or hoarseness.

A ruptured aneurysm usually produces sudden and severe pain, and depending on the location and amount of bleeding, shock, loss of consciousness and death. Emergency surgery is necessary to stop the bleeding.

In some cases, the aneurysm may leak blood, causing pain without the rapid deterioration characteristic of a rupture. Also, clots often form in the aneurysm, creating danger of embolisms in distant organs.

In some cases, the aneurysm may dissect into the wall of an artery, blocking some of the branches. Dissecting aneurysms usually occur in the aortic arch (near its origin, as it leaves the heart) or start in the descending thoracic portion of the aorta after it gives off the branches to the head and arms. Symptoms vary according to the part of the body that is being deprived of blood; they are usually sudden, severe and require emergency treatment.


Tests To Diagnose Aneurysms include:

Angiogram. An x-ray examination of the arteries, veins or heart chambers, obtained by injecting a radiopaque (contrasting dye) into the bloodstream to make these structures more visible.

Magnetic resonance imaging (MRI). A diagnostic technique that uses the response of atoms to a strong magnetic field to produce cross-sectional images of soft tissues, such as veins and arteries.

Spinal tap. A puncture of the spinal cavity with a needle to extract the spinal fluid for diagnostic purposes.

Ultrasound. The use of high-frequency sound waves to produce an image or photograph of an organ or tissues.

Echocardiography. A diagnostic procedure that uses ultrasound waves to visualize structures within the heart.

X-ray. A photograph obtained by bombarding a target in a vacuum tube with high-velocity electrons, enabling them to penetrate solid matter and act on photographic film.


Drugs may be prescribed to lower blood pressure and reduce the risk of rupture. Abdominal aneurysms that are large or increasing in size should be treated surgically. Enlarging thoracic aneurysms should be considered for surgery. A dissecting or ruptured aneurysm requires emergency surgery.


What tests are needed to diagnose an aneurysm?

How are these tests performed and are there any risks?

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Congenital aneurysms cannot be prevented. A healthy lifestyle (a low-fat diet, regular exercise and abstinence from smoking) can help prevent or slow down the course of atherosclerosis, a predisposing factor in the development of other aneurysms. Hypertension should be carefully controlled to prevent aneurysm formation or extension.