Potentially life-threatening emergency
Abdominal aortic aneurysm
Alerts and Notices
Synopsis
Hemodynamically unstable patient:
- Two large bore intravenous (IV) catheters
- Blood pressure control
- Pain control
- Computed tomography angiography (CTA) imaging is preferred. Testing for renal function is not necessary if there is a high index of suspicion for abdominal aortic aneurysm (AAA); there is a weak association between contrast and acute kidney injury (AKI), and the risks outweigh the benefits.
- Consultation with vascular surgery does not need to be delayed by imaging confirmation in the setting of an unstable patient with a high index of suspicion.
- Bedside ultrasound may show a positive focused assessment with sonography in trauma (FAST) examination in patients with a ruptured AAA, although it may be negative if the bleed is retroperitoneal. Ultrasound is not sensitive for rupture.
- The aorta diameter is measured from outer wall to outer wall. A common pitfall is the misinterpretation of thrombus with the outer wall of the aorta.
AAA is defined as a focal, full-thickness dilation of the abdominal aorta that is 50% or more of the regular diameter, or 3 cm or larger. The abdominal aorta is retroperitoneal and lies between the diaphragm and aortic bifurcation, with about 80% of aneurysms arising infrarenally. They are most commonly degenerative in patients with atherosclerosis; 5%-10% are inflammatory and are more often symptomatic.
AAAs are most commonly diagnosed in men with a smoking history, but other risk factors for development are advanced age, other aneurysm, atherosclerotic disease, hypertension, hypercholesterolemia, chronic obstructive pulmonary disease (COPD), a family history of AAA, and White race. In women, 3 cm or larger is aneurysmal, but aortic size index (ASI, diameter in cm / body surface area [BSA]) is a better predictor of clinical events than diameter alone.
General size classifications:
- Small: < 4 cm
- Medium: 4-5.5 cm
- Large: > 5.5 cm
- Very large: ≥ 6 cm
Identifying an AAA is essential, as mortality associated with rupture is up to 80% and is as high as 50%-70% in patients who make it to the hospital after a rupture. Current guidelines recommend screening for AAA in men aged 65-75 years who have ever smoked and in men or women who have a first-degree relative with an AAA.
Related topic: cystic medial necrosis
Codes
ICD10CM:I71.3 – Abdominal aortic aneurysm, ruptured
I71.4 – Abdominal aortic aneurysm, without rupture
SNOMEDCT:
233985008 – Abdominal aortic aneurysm
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
Differential for back, abdominal, or flank pain that may be associated with a symptomatic AAA:- Cholecystitis
- Acute pancreatitis
- Radiculopathy
- Vertebral compression fracture
- Nephrolithiasis
- Pyelonephritis
- Peptic ulcer disease
- Mesenteric ischemia
- Acute coronary syndrome
- Coronary artery disease
- Appendicitis
- Diverticulitis
- Esophagitis
- Achalasia
- Gastritis
- Strangulated hernia
- Ruptured visceral artery aneurysms
- Pancreatic pseudocyst
- Heart failure (secondary to diffuse live enlargement)
- Tumors
- Diverticular abscess
Best Tests
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:08/07/2022
Last Updated:11/29/2022
Last Updated:11/29/2022
Potentially life-threatening emergency
Abdominal aortic aneurysm