Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

For further information, see CMDT Part 12-09: Abdominal Aortic Aneurysm

Key Features

Essentials of Diagnosis

  • Most aortic aneurysms are asymptomatic until catastrophic rupture

  • 80% of abdominal aortic aneurysms measuring 5 cm are palpable; the usual threshold for treatment is 5.5 cm

  • Back or abdominal pain with aneurysmal tenderness may precede rupture

  • Hypotension

  • Excruciating abdominal pain that radiates to the back

General Considerations

  • The aorta of a healthy young man measures approximately 2 cm

  • An aneurysm is considered present when the aortic diameter exceeds 3 cm

  • Aneurysms rarely cause rupture until diameter exceeds 5 cm

  • 90% of abdominal atherosclerotic aneurysms originate below the renal arteries

  • Aortic bifurcation is usually involved

  • Common iliac arteries are often involved


  • Found in 2% of men over age 55

  • Male to female ratio is 4:1

Clinical Findings

Symptoms and Signs

  • Most asymptomatic aneurysms are discovered on ultrasound or CT imaging as part of a screening program or during the evaluation of unrelated abdominal symptoms

  • Symptomatic aneurysms

    • Mild to severe midabdominal pain due to aneurysmal expansion often radiates to lower back

    • Pain may be constant or intermittent, exacerbated by even gentle pressure on aneurysm sack, and may also accompany inflammatory aneurysms

  • Inflammatory aneurysms have an inflammatory peel, similar to the inflammation seen with retroperitoneal fibrosis, surrounds the aneurysm and encases adjacent retroperitoneal structures, such as the duodenum and, occasionally, the ureters

  • Ruptured aneurysms

    • Severe pain

    • Palpable abdominal mass

    • Hypotension

    • Free rupture into the peritoneal cavity is lethal

    • Most aneurysms have a thick layer of thrombus lining the aneurysmal sac

    • Embolization to lower extremities is rarely seen

Differential Diagnosis

  • Perforated viscus, eg, peptic ulcer, appendix, gallbladder, diverticulitis

  • Pancreatitis or pancreatic pseudocyst

  • Urinary calculi

  • Pyelonephritis

  • Gastritis

  • Intestinal ischemia

  • Bowel obstruction

  • Musculoskeletal pain

  • Sudden death due to other causes, eg, ventricular fibrillation, myocardial infarction, pulmonary embolism


Laboratory Tests

  • Hematocrit will be normal, since there has been no opportunity for hemodilution

  • Patients with aneurysms may have the following coexisting conditions, which typically occur in older men who smoke or have smoked cigarettes:

    • Coronary artery disease

    • Carotid disease

    • Kidney impairment

    • Emphysema

  • Preoperative testing may indicate the presence of these comorbid conditions

Imaging Studies

  • Abdominal ultrasonography

    • Diagnostic study of choice for initial screening

    • Screening guidelines

  • Recommend screening in men 65–75 years old with exposure to 100 or more lifetime cigarettes

  • Conflict on whether women with the same exposure should be screened

  • Do not recommend repeated screening if the aorta shows no enlargement

  • While patients are monitored, smoking cessation and treatment of underlying hypertension, hyperlipidemia, and diabetes should be considered

  • Abdominal or back radiographs: curvilinear calcifications outlining portions ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.