Abdominal aortic aneurysm

Background

• Infrarenal diameter >3cm or >50% increase in size of diameter
• Rupture Risk
  • <4cm: low risk for rupture
  • 4-5cm: 5 year risk 3-12%
  • >5cm: 25-41%
  • Rupture poss at any size, most commonly >5cm

Risk Factors

1. Age
   1. Prevalence is negligible in age < 50 yrs
2. Smoking
   1. Risk factor most strongly assoc with AAA
   2. Also promotes the rate of aneurysm growth
3. Family history
4. HTN

Diagnosis

• Triad of pain, hypotension, pulsatile mass
  • Pain often described as sudden, severe, radiating to back
• Syncope (10%)
• Pain + AAA = rupture until proven otherwise
• Acute abdomen + hypotension = possible rupture

Workup

• Ultrasound
  • ~100% sensitive for increased diameter
  • Cannot reliably visualize rupture
• CT
  • ~100% sensitive for incr diameter and rupture
  • IV contrast is preferred but not essential

Differential Diagnosis

• Renal Colic
• Pancreatitis
• Mesenteric ischemia
• Cholecystitis
• Appendicitis
• Diverticulitis
• ACS
• Musculoskeletal backpain

See Abdominal Pain

Treatment

Rupture

1. Immediate surgery consultation/ go to OR
2. BP control
   1. 1. Controversial
         1. Too little (ischemia), too much (increased bleeding)
         2. LOC may be better guide than BP
         3. Do not waste time in ED trying to "stabilize" pt
3. Crossmatch 6 units of pRBC
4. Pain control (avoid hypotension)

Asymptomatic

• Prompt vascular surgery outpatient follow-up appt

Source

• Tintinalli
• UpToDate
• Rosen's