Aortic aneurysm
| Aortic aneurysm | |
|---|---|
 |
|
| CT reconstruction image of an abdominal aortic aneurysm | |
| Classification and external resources | |
| Specialty | Vascular surgery |
| ICD-10 | I71 |
| ICD-9-CM | 441 |
| OMIM | 100070 |
| DiseasesDB | 792 |
| eMedicine | emerg/942 med/2783 emerg/27 radio/1 med/3443 |
| MeSH | D001014 |
An aortic aneurysm is an enlargement (dilation) of the aorta to greater than 1.5 times normal size. They usually cause no symptoms except when ruptured. Occasionally, there may be abdominal, back, or leg pain.
They are most commonly located in the abdominal aorta, but can also be located in the thoracic aorta. Aortic aneurysms cause weakness in the wall of the aorta and increase the risk of aortic rupture. When rupture occurs, massive internal bleeding results and, unless treated immediately, shock and death can occur.
Screening with ultrasound is indicated in those at high risk. Prevention is by decreasing risk factors such as smoking. Treatment is either by open or endovascular surgery. Aortic aneurysms resulted in about 152,000 deaths in 2013, up from 100,000 in 1990.
Aortic aneurysms are classified by their location on the aorta.
Most intact aortic aneurysms do not produce symptoms. As they enlarge, symptoms such as abdominal pain and back pain may develop. Compression of nerve roots may cause leg pain or numbness. Untreated, aneurysms tend to become progressively larger, although the rate of enlargement is unpredictable for any individual. Rarely, clotted blood which lines most aortic aneurysms can break off and result in an embolus.
Aneurysms can be found on physical examination. Medical imaging is necessary to confirm the diagnosis and to determine the anatomic extent of the aneurysm. In patients presenting with aneurysm of the arch of the aorta, a common sign is a hoarse voice from stretching of the left recurrent laryngeal nerve, a branch of the vagus nerve that winds around the aortic arch to supply the muscles of the larynx.
Abdominal aortic aneurysms (AAAs) are more common than their thoracic counterpart. One reason for this is that elastin, the principal load-bearing protein present in the wall of the aorta, is reduced in the abdominal aorta as compared to the thoracic aorta. Another is that the abdominal aorta does not possess vasa vasorum, the nutrient-supplying blood vessels within the wall of the aorta. Most AAA are true aneurysms that involve all three layers (tunica intima, tunica media and tunica adventitia). The prevalence of AAAs increases with age, with an average age of 65–70 at the time of diagnosis. AAAs have been attributed to atherosclerosis, though other factors are involved in their formation.
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