Abdominal aortic aneurysm involves a dilation, stretching, or ballooning of the aorta. The exact cause is unknown, but risk factors include atherosclerosis and hypertension. Abdominal aortic aneurysm may be caused by infection, congenital weakening of the connective tissue component of the artery wall, or trauma. (An aneurysm caused by trauma is rare.)

Abdominal aortic aneurysm can affect anyone, but it is most often seen in men aged 40 to 70. A common complication is rupture. This is a medical emergency where the aneurysm breaks open, resulting in profuse bleeding. Rupture occurs more frequently in patients with larger aneurysms. Aortic dissection occurs when the lining of the artery tears and blood leaks into the wall of the artery.

In children, abdominal aortic aneurysm can result from blunt abdominal injury or from Marfan's syndrome.

Symptoms of abdominal aortic aneurysm may include a pulsating abdominal mass with rhythmic throbbing. However, there are often no symptoms.

Symptoms of rupture:

• Pulsating sensation in the abdomen
• Pain in the abdomen
  • Severe, sudden, persistent or constant
  • Not colicky or spasmodic
  • May radiate to groin, buttocks, or legs
  • May begin suddenly
• Abdominal rigidity
• Pain in the lower back
  • Severe, sudden, persistent
  • May radiate
• Paleness
• Rapid pulse
• Dry skin/mouth
• Excessive thirst
• Anxiety
• Nausea and vomiting
• Light-headedness with upright posture
• Fainting with upright posture
• Excessive sweating
• Clammy skin
• Fatigue (tiredness or weariness)
• Heartbeat sensations
• Rapid heart rate (tachycardia) when rising to standing position
• Impaired ability to concentrate
• Shock
• Abdominal mass

Note: Aneurysms may develop slowly over many years and often have no symptoms. If an aneurysm expands rapidly, tears open (ruptured aneurysm), or blood leaks along the wall of the vessel (aortic dissection), the above symptoms may develop suddenly.

Your health care provider may listen to your abdomen with a stethoscope (auscultation). If you have an abdominal aortic aneurysm, there will be a "blowing" murmur over the aorta or a "whooshing" sound (bruit).

The health care provider will also perform a physical examination of your abdomen. If a rupture is suspected, he or she may also conduct an examination for signs of blood loss (hypovolemia) and an evaluation of lower extremity pulses and circulation.

Abdominal aortic aneurysm may be diagnosed with these tests:

• Abdominal X-ray
• Abdominal ultrasound
• MRI of abdomen
• CT scan of abdomen
• Angiography of aorta

A CBC may indicate loss of blood.

If the aneurysm is small and there are no symptoms (for example, if the aneurysm is found during a routine physical examination), your health care provider may recommend periodic evaluation, usually with annual ultrasound examination, to watch for changes.

Symptomatic aneurysms usually require surgical treatment to prevent complications. Antihypertensive medications may be prescribed before surgery to reduce blood pressure. Other medications may include analgesics to relieve pain.

Surgical repair or replacement of the section of aorta is recommended for patients with symptoms, as they are at high risk of fatal rupture. Repair is also recommended for patients with aneurysms greater than 5 cm in diameter. The goal of treatment is to perform surgery before complications develop.

The risk of complications increases as the size of the aneurysm increases. Because surgery for abdominal aortic aneurysm is risky, the surgeon may wait for the aneurysm to expand to a certain size before operating (that is, when the risk of complications exceeds the risk of surgery).

The outcome is usually good when an aneurysm is monitored carefully and if surgical repair is performed before the aorta ruptures.

Aortic rupture is life-threatening. Less than 50% of people with a ruptured abdominal aortic aneurysm survive.

• Aortic rupture
• Bleeding from the aorta
• Hypovolemic shock
• Arterial embolism
• Insufficient circulation past the aneurysm
• Irreversible damage to the kidneys (kidney failure)
• Myocardial infarction
• Stroke
• Aortic dissection

Go to the emergency room or call the local emergency number (such as 911) if you develop severe abdominal pain or other symptoms that are suggestive of an abdominal aortic aneurysm.

Avoid blunt trauma to the abdomen. Take measures to prevent atherosclerosis and hypertension from developing.