Abdominal Aortic Aneurysm (AAA)

Definition:

Localized dilation or bulge in the abdominal aorta. Risk of rupture is related to the degree of dilation.

Causes

The cause of AAA is degradation of the layers of the aorta, with inflammatory infiltrates in both the intima and tunica media. The major risk factors include: atherosclerosis, smoking,  male gender, increasing age (aneurysms are uncommon in those under 60s), familial, infection and trauma

Examination:

Most patients are asymptomatic with visible or palpable pulsatile lower abdominal swelling. First observe the abdomen at eye-level looking for swelling pulsations. Palpation at the level of the umbilicus may reveal enlargement of the aorta with expansile pulsations (A solid mass adjacent to the aorta will be pulsatile but not expansile). Detection of bruits is not confirmatory of AAA. Patient may also present with peripheral emboli in the toes (“blue toe syndrome”). Confirmation of diagnosis and aneurysm size is by ultrasound. The major risk is dissection which typically presents with sudden, severe back, abdominal or inguinal pain with hypotension and possible syncope. It is a medical emergency.