HWN Suggests

Impending Doom: AAA

Nothing strikes more fear and suspense in healthcare than when discussing “abdominal aortic aneurysms” (AAA). Perhaps it is due to their utterly silent growth and potential for catastrophic rupture. AAA is the most common “true” aneurysm in the human body. In developed countries, the prevalence is estimated between 2-8%, with men nearly twice as affected. From screening, it is estimated nearly 1,000,000 people in the US alone have a AAA. Since the 1990’s, mortality from AAA has dramatically decreased by ~50%, likely secondary to rates of smoking cessation, more awareness and screening, and improved vascular surgery techniques. It continues to remain a very difficult diagnosis due to its ability…

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Featured

 AAA-OK: Approach to Imaging of Abdominal Aortic Aneurysm

Around 30% of symptomatic AAAs are misattributed to non-vascular causes leading to poor outcomes. The classic triad of abdominal or flank pain, hypotension, and a pulsatile mass occur in only half of patients presenting with a ruptured AAA (rAAA).

 The Crashing Abdominal Aortic Aneurysm Patient

Presence and expansion of AAAs is usually a silent disease. When rupture does occur, it usually happens quickly without a typical presentation.

Articles of Interest

The Clinical Challenges of Abdominal Aortic Aneurysm: Rapid, Systematic Detection and Outcome-Effective Management

Given equal availability of US and CT, bedside US is the test to obtain in order to answer the question of whether there is an aneurysm. It is nearly 100% sensitive for diagnosing the presence of an AAA, it can be executed in a matter of minutes, and it does not require unstable patients to leave the department.1 While much less accurate than CT in detecting actual rupture, if the patient has the symptoms of rupture and presence of an AAA, this usually is all the information required for the consultant to take the patient to the OR.

Intern Ultrasound of the Month: AAA & Ureteral Compression

Have a low threshold to evaluate the aorta with POCUS in patients with abdominal, flank, back pain, especially if elderly and/or unstable

Tips and Tricks: Big Red - The Aorta and How to Improve Your Image

Although the gold standard for diagnosis is CT angiogram, it is not appropriate for the unstable patient. Unfortunately, with physical exam alone, a ruptured AAA is misdiagnosed in 32% of patients, usually as ureteral colic and myocardial infarction, with only 61% of patients presenting with the classic triad of abdominal pain, hypotension, and a pulsatile mass. Fortunately, the use of point-of-care ultrasound (POCUS) quickly identifies AAA with sensitivity and specificity approaching 99% and 98% respectively.

Resources

CDEM

AAA should be in the differential diagnosis for any patient over 50 with abdominal, back, or flank pain, especially those with undifferentiated shock.

emDOCs

Bedside ultrasound has emerged as the test of choice in this case. Ultrasound has a sensitivity of 98% in fasted patients undergoing screening, and while bowel gas and body habitus can hinder the exam, this is less of an issue in imaging the larger aneurysms that are likely to present ruptured. To obtain images of the aorta, a low frequency curvilinear probe is used.

International Emergency Medicine Education Project

Abdominal aortic aneurysms are asymptomatic until they rupture, resulting in a mortality of 85 to 90%.

Life in the Fastlane

... isolated pain in abdomen, epigstrium or back (contained leaks typically present with back pain).

Core EM

Consider ruptured AAA in patients (especially those > 50 years of age) with unexplained hypotension, back or abdominal pain.