Ultrasound Case of the Month: August 2018

The Case

This is an 82 year-old male who presented to the ED with acute chest pain and palpitations. He had a known history of AAA s/p repair. Patient denied abdominal, back, or flank pain. There was no loss of consciousness. An EKG was performed and was consistent with SVT with aberrancy. A bedside abdominal ultrasound was performed and the following images were obtained:

Figure 1: Proximal axial abdominal aortic ultrasound

Figure 2: Longitudinal abdominal aorta ultrasound

Figure 3: Distal axial abdominal aorta ultrasound

Diagnosis

Known AAA s/p repair (also SVT with aberrancy)

Case Follow-up

The patient remained HDS and adenosine was given with good effect. He was admitted to medicine, and had no further episodes of SVT. He was discharged home with cardiology follow up.

Discussion

The images were acquired using the curvilinear probe. The probe was placed on the abdomen just superior of the umbilicus and just left of midline. Both longitudinal and axial views were acquired.

Ultrasound is the initial test of choice for suspected AAA in the ED. It has sensitivity of 94-99%, and has been shown to decrease mortality in AAA patients by 20-50% compared to CT--likely due to decreased time to diagnosis.

A normal abdominal aorta is typically < 3cm in diameter. A complete AAA ultrasound should evaluate the aorta from the xiphoid process past the aortic bifurcation. US may be considered positive if the aorta is >3 cm in a patient with clinical concern for AAA,  or > 5 cm without clinical concern.

Faculty Reviewer: Dr. Kristin Dwyer

For an in-depth tutorial on the abdominal aorta ultrasound, check out this video from EM:RAP HD:

Additional Resources

https://cdemcurriculum.com/bedside-ultrasound-aaa-examination/

https://radiopaedia.org/articles/abdominal-aortic-aneurysm

https://www.acep.org/sonoguide/abdominal_aortic_aneurysm.html

http://5minsono.com/aaa/