An abnormal dilation of the abdominal portion of the aorta (the major artery from the heart).
Causes, incidence, and risk factors
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 rarely, from trauma. Abdominal aortic aneurysm can affect anyone, but it is most often seen in men 40 to 70 years old. A common complication is ruptured aortic aneurysm. This is a medical emergency where the aneurysm breaks open, resulting in profuse bleeding into the abdominal cavity. Ruptured aneurysm occurs more frequently in patients with larger (>5cm) aneurysms. Aortic dissection occurs when the lining of the artery tears and blood leaks into the wall of the artery. An aneurysm that dissects is at even greater risk of rupture. In children, abdominal aortic aneurysm can result from blunt abdominal injury or from Marfan's syndrome .
Signs and tests
Listening to the abdomen with a stethoscope ( auscultation ) shows a "blowing" murmur over the aorta or a "whooshing" sound (bruit). Physical examination of the abdomen is performed. If a rupture is suspected, physical examination for signs of blood loss ( hypovolemia ) and an evaluation of lower extremity pulses and circulation are performed. Abdominal aortic aneurysm may show on these tests:
Abdominal X-rayAbdominal ultrasoundMRI of abdomenCT scan-abdominalAngiography of aorta A CBC may indicate loss of blood.
Treatment
If the aneurysm is small and there are no symptoms (for example, if the aneurysm is found during a routine physical examination ), periodic evaluation, usually with annual ultrasound examination, to watch for changes may be recommended. Symptomatic aneurysms require surgical treatment to prevent complications. Anti-hypertensive medications may be prescribed preoperatively 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 timely surgical intervention 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 (usually >5 cm) before operating (that is, when the risk of complications exceeds the risk of surgery).
Expectations (prognosis)
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 all people with a ruptured abdominal aortic aneurysm survive.
Calling your health care provider
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.
Prevention
Avoid blunt trauma to the abdomen, atherosclerosis , and hypertension .