About 95% of abdominal aortic aneurysms result from arteriosclerosis or atherosclerosis; the rest result from congenital cystic medial necrosis, trauma, syphilis, and other inflammatory or infectious causes. Chronic obstructive pulmonary disease, hypertension, and smoking of cigarettes, cigars, or pipes are risk factors for the development of an abdominal aneurysm.

More than 50% of all patients with untreated abdominal aneurysms die of hemorrhage and shock from aneurysmal rupture within 2 years of diagnosis. More than 85% die within 5 years.

Most patients with abdominal aneurysms are asymptomatic until the aneurysms enlarge and compress surrounding tissue. A large aneurysm may produce signs and symptoms that mimic those of renal calculi, lumbar disk disease, and duodenal compression.

The patient may complain of gnawing, generalized, steady abdominal pain or lower back pain that is unaffected by movement. He may have a sensation of gastric or abdominal fullness caused by pressure on the GI structures.

Sudden onset of severe abdominal pain or lumbar pain that radiates to the flank and groin from pressure on lumbar nerves may signify enlargement and imminent rupture. If the aneurysm ruptures into the peritoneal cavity, severe and persistent abdominal and back pain, mimicking renal or ureteral colic pain, occurs. If it ruptures into the duodenum, GI bleeding occurs with massive hematemesis and melena.

Inspection of the patient with an intact abdominal aneurysm usually reveals no significant findings. However, if the person isn’t obese, you may note a pulsating mass in the periumbilical area. Auscultation of the abdomen is the most important diagnostic indicator of disease. Auscultation may reveal a systolic bruit over the aorta caused by turbulent blood flow in the widened arterial segment. Hypotension occurs with aneurysm rupture.

Palpation of the abdomen may disclose some tenderness over the affected area. A pulsatile mass may be felt; however, avoid deep palpation to locate the mass because this may cause the aneurysm to rupture. (See Aneurysms and the elderly, page 2.)