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What is an aneurysm?

An aneurysm is a bulging, weakened area in the wall of a blood vessel. An aneurysm may occur in any blood vessel, but most often develops in an artery rather than a vein. An aneurysm can be characterized by its location, shape, and cause. 

An aneurysm may be located in many areas of the body, such as blood vessels of the brain (cerebral aneurysm), the aorta (the largest artery in the body), the neck, the intestines, the kidney, the spleen, and the vessels in the legs (iliac, femoral, and popliteal aneurysms). The most common location of an aneurysm is the aorta, which carries oxygenated blood from the heart to the body. The thoracic aortic aneurysm occurs in the short segment of the aorta in the chest cavity. The abdominal aortic aneurysm occurs in the section of the aorta that runs through the abdomen. 

What causes an aneurysm to form?

An aneurysm may be caused by multiple factors that result in the breaking down of the components of the artery wall that provide support and stabilize the wall. The exact cause isn't fully known. Atherosclerosis (hardening of the arteries with a sticky substance called plaque) is thought to play an important role. Risk factors associated with atherosclerosis include, but are not limited to:

Risk factors you can’t control:

  • Older age
  • Male
  • Family history
  • Genetic factors

Risk factors you can control:

  • High cholesterol
  • High blood pressure
  • Smoking
  • Diabetes
  • Obesity

Other specific causes of aneurysms are related to the location of the aneurysm. Examples of aneurysms in the body and their additional causes may include, but are not limited to:


Type of aneurysm

Causes of aneurysms

Abdominal aortic aneurysm (AAA)

  • Atherosclerosis (especially in the segment of the abdominal aorta below the kidneys, called an infrarenal aortic aneurysm)
  • Genetic disorders
  • Giant cell arteritis (a disease that causes inflammation of the temporal arteries and other arteries in the head and neck, causing the arteries to narrow, reducing blood flow in the affected areas; may cause persistent headaches and vision loss)
  •  Infection

Cerebral aneurysm

  • Congenital (present at birth)
  • High blood pressure
  • Atherosclerosis
  • Head injury

Common Iliac artery aneurysm

  • Atherosclerosis
  • Pregnancy
  • Infection
  • Injury after lumbar or hip surgery

Femoral and popliteal artery aneurysm

  • Atherosclerosis
  • Injury
  • Congenital disorders

What are the symptoms of an aneurysm?

Aneurysms may have no symptoms. If symptoms are present, they will depend on the location of the aneurysm in the body. Pain is the most common symptom regardless of the aneurysm location.

Symptoms that may occur with different types of aneurysms may include, but are not limited to:


Type of aneurysm

Symptoms associated with aneurysm type

Abdominal aortic aneurysm (AAA)

Constant pain in abdomen, chest, lower back, or groin area

Cerebral aneurysm

Sudden severe headache, nausea, vomiting, visual disturbance, loss of consciousness

Common iliac aneurysm

Lower abdominal, back, and/or groin pain

Femoral and popliteal artery aneurysm

Easily palpated (felt) pulsation of the artery located in the groin area (femoral artery) or on the back of the knee (popliteal artery), pain in the leg, sores on the feet or lower legs 


The symptoms of an aneurysm may resemble other medical conditions or problems. Always consult your doctor for more information.

How are aneurysms treated?

What tests you’ll have depends on the location of the aneurysm. In addition to a complete medical history and physical exam, diagnostic procedures for an aneurysm may include any, or a combination, of the following:

  • Computed tomography (CT or CAT) scan. This diagnostic imaging procedure uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than standard X-rays.
  • Magnetic resonance imaging (MRI). An MRI uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within the body.
  • Echocardiogram (echo). This procedure evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
  • Arteriogram (angiogram). This is an X-ray image of the blood vessels used to evaluate various conditions, such as aneurysm, stenosis (narrowing of the blood vessel), or blockages. A dye (contrast) will be injected through a thin flexible tube placed in an artery. This dye will make the blood vessels visible on the X-ray.
  • Ultrasound. An ultrasound uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. An ultrasound is used to view internal organs as they function, and to assess blood flow through various vessels.

What is the treatment for aneurysms?

Specific treatment will be determined by your doctor based on:

  • Your age, overall health, and medical history
  • Extent of the disease (location, size, and growth rate of the aneurysm)
  • Your signs and symptoms
  • Your tolerance of specific medications, procedures, or therapies
  • Expectations for the course of the disease
  • Your opinion or preference

Treatment options for an aneurysm may include one or more of the following:

  • Ultrasound monitoring. These procedures are used to monitor the size and rate of growth of the aneurysm every 6 months to 12 months as part of a "watchful waiting" approach for smaller aneurysms. 
  • Controlling or modifying risk factors. Steps such as quitting smoking, controlling blood sugar if diabetic, losing weight if overweight or obese, and controlling dietary fat intake may help to control the progression of the aneurysm. 
  • Medication. Medication can control factors such as high cholesterol and high blood pressure. 
  • Surgical repair. Surgical repair of the aneurysm can be done with large incisions and grafts or with smaller incisions, X-ray images and a stent-graft combination.

What are the complications of aneurysms?

A dissection is a tear in the artery wall that separates the 3 layers of the wall caused by the ballooning of an aneurysm.  

Because an aneurysm may continue to increase in size, along with progressive weakening of the artery wall, treatment is required to prevent rupture of an aneurysm. The larger an aneurysm becomes, the greater the risk for rupture (bursting). With rupture, life-threatening hemorrhage (uncontrolled bleeding), and possibly death, may result. Loss of blood flow to the area the artery provides circulation to can cause organ and tissue death which may lead to amputation of the dead tissue.

Living with an aneurysm

Until your aneurysm reaches the point where it needs to be repaired, it’s very important to follow your health care provider’s recommendations closely.

  • Have ultrasound screenings done as often as recommended
  • Follow recommendations regarding diet, exercise and physical activity, and weight management
  • Take medications as prescribed

When should I call my health care provider?

If your symptoms get worse or you have new symptoms, notify your health care provider. If you have a sudden, severe pain in the area of the aneurysm, you should be seen immediately, as this could be a sign that the aneurysm has ruptured, which is a medical emergency.

Key points

  • Aneurysms are bulging, weakened areas of an artery wall and can occur anywhere in the body.
  • The most common symptom is pain in the area of the aneurysm.
  • Aneurysms are repaired once they reach a certain size to prevent rupture of the blood vessel.
  • Treatment of aneuryms also includes controlling risk factors such as blood pressures, cholesterol, diabetes, and stopping smoking which may require changes in lifestyle and medications.


Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.