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, rad 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

Treatment

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

Source

Tintinalli, UpToDate, Rosen's