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Ruptured AAA

Ruptured AAA

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Case Study

68 year old male with a history of COPD, hypertension, and hypercholesterolemia presents to the emergency department with 8 hours of progressively worsening abdominal pain. The pain is diffuse, though occasionally sharp in the LLQ. The patient denies chest pain, SOB, N/V/D, hematochezia and constipation.

He takes 81mg aspirin and 40mg atorvastatin daily. He has smoked 1 pack per day for 42 years.

Vitals: HR: 92 | BP: 110/74 | RR: 18 | spO2 98% on RA | T: 37 ºC

Exam: Generally appears well, though anxious, lungs clear bilaterally, mild tachy though regular, abdomen with mild diffuse tenderness, not peritonitic, no masses felt, distal pulses 2+ throughout, no LE edema

Let’s recap…

Our patient is a male, who currently smokes, and likely has some degree of CAD given he’s on a statin for hyperlipidemia. At least he’s not hypertensive, right? 😬

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Law of LaPlace

How could you forget? Laplace’s law tells us wall tension (T) equals the product of pressure across the vessel wall (P) and the vessel’s radius (r), or T = P x r. As the aorta expands, the wall weakens, leading to further dilation. Rupture occurs when tension on the vessel wall exceeds the strength of the vessel - somewhere around 5 cm.

While CT with contrast is still considered gold standard for diagnosing ruptured AAA, ultrasound is being used with increasing frequency. The patient’s clinic status may be too tenuous for a trip to CT, which leaves ultrasound as a great option for quickly identifying AAA at bedside. 

In this sagittal view on ultrasound, we can see a large dilated aorta consistent with AAA. This finding, along with abdominal pain and hypotension, should prompt an immediate call to a vascular surgeon for operative management. You should also turn the probe to get the axial image. Consider a FAST to look for free fluid (keep in mind this won’t show retroperitoneal fluid).

In the meantime, start standard resuscitation. Go easy on the fluids though, the limited data we have shows aggressive fluids may be harmful.

β-blockers have been shown to reduce dysrhythmia and cardiac ischemia but don’t reduce mortality or shorten hospital stays. Generally, standard practice is to give it. Esmolol is often a good choice, but any short acting IV β-blocker will work. Just get them to the OR.

Management is more straightforward than a lot of what you’ll deal with. Just keep it in the back of your head and know how to look for AAA if it’s on the differential.

 

References

Abdominal Pain. In: Stern SC, Cifu AS, Altkorn D. eds. Symptom to Diagnosis: An Evidence-Based Guide, 3e New York, NY: McGraw-Hill; 2014. http://accessmedicine.mhmedical.com.liboff.ohsu.edu/content.aspx?bookid=1088&sectionid=61696569. Accessed September 15, 2018.

Chaikof EL, Brewster DC, Dalman RL, et al. SVS practice guidelines for the care of patients with an abdominal aortic aneurysm: executive summary. J Vasc Surg 2009; 50:880

Gokani VJ, Sidloff D, Bath MF, Bown MJ, Sayers RD, Choke E. A retrospective study: Factors associated with the risk of abdominal aortic aneurysm rupture. Vascul Pharmacol. 2015;65-66:13-16.

Lederle FA, Johnson GR, Wilson SE, et al. The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators. Arch Intern Med. 2000;160(10):1425-1430

Prince LA, Johnson GA. Aneurysmal Disease. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e New York, NY: McGraw-Hill; 2016. http://accessmedicine.mhmedical.com.liboff.ohsu.edu/content.aspx?bookid=1658&sectionid=109388462. Accessed September 15, 2018

Ultrasound image credit:

Bryson Hicks, MD, Assistant Professor, Department of Emergency Medicine
Co-Director, Emergency Medicine Ultrasound Fellowship, OHSU Emergency Medicine Residency

 

Signed: Jordan Wackett, MD, MPH & Jesse Lee, MD

Cosigned: Edward Lew, MD

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