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Make the Diagnosis: Abdominal Aortic Aneurysm

Prior Probability

Abdominal aortic aneurysms occur in 4% to 8% of older men. The prevalence in older women is less than 2%.

Population for Whom AAA Should Be Considered

  • Age older than 50 years

  • History of ever smoking

  • Male sex

  • White race

  • Family history of AAA

Detecting an Abdominal Aortic Aneurysm

The size of an aneurysm affects the clinician's ability to detect it (Table 2-4).

Table 2-4Likelihood Ratios Vary With the Size of the Aneurysm

Clinicians can detect asymptomatic AAAs. The ability to detect the aneurysm relates, in part, to patient characteristics. The examination should focus on the width of the palpated abdominal aorta. Fortunately, the examination results are just as good for the obese as for the nonobese patient when the clinician detects an aneurysm. However, the examination is not as efficient at ruling out an aneurysm in obese patients or in those who cannot relax their abdomen to facilitate the examination.

Reference Standard Tests

Imaging studies (ultrasonography or computed tomography).

Original Article: Does This Patient Have Abdominal Aortic Aneurysm?

Clinical Scenarios


A 60-year-old man requests a physical examination because a friend recently died suddenly from a ruptured abdominal aortic aneurysm (AAA). Your examination reveals nothing abnormal. After reassuring the patient, you are left wondering whether you might have missed an AAA large enough to warrant surgical repair.


A thin 80-year-old woman observes that she can feel her abdomen pulsating against her belt. While examining her abdomen, you find an easily palpable, strongly pulsating aorta that you measure to be about 2 cm wide. You wonder whether you should order an ultrasonographic examination.


You are asked to see a 75-year-old man with 12 hours of right flank and abdominal pain, constipation, urinary frequency, urgency, dysuria, and leukocytosis and who is about to be sent home on treatment for pyelonephritis. Deep palpation of the abdomen is difficult, but you faintly discern a large pulsatile mass. You order computed tomography, which confirms an AAA with bleeding into the retroperitoneum, and the patient is taken to the operating room.

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