An aneurysm is when a blood vessel becomes abnormally large or balloons outward. The abdominal aorta is a large blood vessel that supplies blood to your abdomen, the pelvis, and legs.

The exact cause is unknown, but risk factors for developing an aortic aneurysm include:

• High blood pressure
• Smoking
• High cholesterol
• Obesity
• Emphysema
• Genetic factors
• Male gender

An abdominal aortic aneurysm can develop in anyone, but it is most frequently seen in males over 60 with one or more risk factors. The larger the aneurysm, the more likely it is to rupture.

When an abdominal aortic aneurysm ruptures, it is a true medical emergency. Aortic dissection occurs when the innermost lining of the artery tears and blood leaks into the wall of the artery. This most commonly occurs in the aorta within the chest.

Aneurysms 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), symptoms may develop suddenly.

The symptoms of rupture include:

• Pulsating sensation in the abdomen
• Pain in the abdomen or back -- severe, sudden, persistent, or constant. The pain may radiate to groin, buttocks, or legs.
• Abdominal rigidity
• Anxiety
• Nausea and vomiting
• Clammy skin
• Rapid heart rate when rising to a standing position
• Shock
• Abdominal mass

Your doctor will examine your abdomen. The exam also will include an evaluation of pulses and sensation in your legs.

Abdominal aortic aneurysm may be diagnosed with these tests:

• Abdominal ultrasound
• CT scan of abdomen
• Angiography of aorta