Aortic Aneurysm (Abdominal)
Overview
Plain-Language Overview
Abdominal aortic aneurysm (AAA) is a condition where the large blood vessel that supplies blood to the abdomen, pelvis, and legs becomes abnormally enlarged or bulges. This blood vessel is called the aorta, and when it weakens and expands, it can cause serious health problems. The main concern is that the aneurysm can grow and eventually rupture, leading to life-threatening internal bleeding. People with AAA may not have symptoms until the aneurysm is very large or ruptures. Risk factors include smoking, high blood pressure, and older age. Regular medical check-ups can help detect this condition early. Treatment depends on the size and growth of the aneurysm.
Clinical Definition
Abdominal aortic aneurysm (AAA) is defined as a localized dilation of the abdominal aorta exceeding 3 cm in diameter or more than 50% larger than the normal aortic diameter. The core pathology involves degeneration of the aortic media with loss of elastic fibers and smooth muscle cells, often due to chronic inflammation and proteolytic enzyme activity. The most common cause is atherosclerosis, which weakens the vessel wall. Other contributing factors include smoking, hypertension, and genetic predisposition. The major clinical significance of AAA lies in the risk of rupture, which carries a high mortality rate. Most AAAs are asymptomatic until rupture or rapid expansion occurs. Screening with ultrasound is recommended in high-risk populations to detect aneurysms before complications arise.