|Print Date:||May 25, 2013, 8:10 am|
|Title||Abdominal Aortic Aneurysm|
|Text||Under the subcategory of degenerative aneurysms, abdominal aortic aneurysms are caused by longstanding systemic hypertension. A regional atheroma will result in ischemia and weakening of the vessel wall. Thrombi form in areas of turbid flow. These degenerative aneurysms result in fusiform or saccular dilatation of the vessel wall. The same pathology can occur in other vessels, such as a carotid or intracranial artery.
AAA's affect mainly older hypertensive males. They are areas of dilatation >3cm diameter, located in the descending aorta and distal arch, and 90% originate below the renal arteries. They may be asymptomatic or present as a tender, pulsatile abdominal mass.
Initial imaging workup is with ultrasound, as it will show areas of different echogenicity in the vessel, thrombus, and lumen. CT with IV contrast is best for a detailed visualization of the dimensions of the AAA. Xray may only reveal a AAA with areas of calcification. Angiography is not reliable as it will only show area of blood flow and not the dimension of the thombus or actual vessel wall.
A symptomatic patient deserves an emergent CT scan. An unstable patient with high index of suspicion for AAA should be taken directly to the OR. Areas of dilatation 3cm or more warrant a vascular surgery consult. AAA's of up to 4cm dilatation may be followed with serial ultrasound twice yearly. Greater than 5cm aneurysms should be considered for surgial correction.
|References:||Novelline, RA. Squire's Fundamentals of Radiology. 5th Ed. Pg 472-477.
Sutton, DA. Textbook of Radiologic Imaging. 7th Ed. Pg 423-425.
|Contributor||Adrian N Miclea (Naval Medical Center Portsmouth)|
|Peer Reviewer||Maria Flynn (National Capital Consortium)|
|Record Number||: 6054|
|MedPix® Medical Image Database |
Content Text and Images may be Copyright © 1999 - 2006 by the Original Contributors