Aortocaval fistula

Background

• Complication of abdominal aortic aneurysm
• Rare (<1% of all AAAs, ~3% of ruptured AAAs) but life-threatening (mortality ~50%)
• Caused by inflammation around aorta → adherence of aorta to vein → pressure and erosion into vein → fistula

Clinical Features

• Presentation depends on origin, size, and location of fistula
• Signs/symptoms of AAA (abdominal/flank/back pain, shock if ruptured)
• High-output heart failure
• Pedal edema (due to venous hypertension)
• Renal insufficiency (due to reduced perfusion to kidneys)
• Hematuria
• Bruit

Differential Diagnosis

Diffuse Abdominal pain

• Abdominal aortic aneurysm
  • Aortocaval fistula
• Acute gastroenteritis
• Aortoenteric fisulta
• Appendicitis (early)
• Bowel obstruction
  • Large bowel obstruction
    • Ogilvie's syndrome
  • Small bowel obstruction
• Bowel perforation
• Gastroparesis
• Diabetic ketoacidosis
• Inflammatory bowel disease
• Mesenteric ischemia
• Pancreatitis
• Peritonitis
• Sickle cell crisis
• Spontaneous bacterial peritonitis
• Volvulus

Evaluation

• US to identify AAA
• CT angio

Management

• Treat hypovolemia/shock
• Emergent surgical repair

Disposition

• Admit

See Also

• Abdominal aortic aneurysm

References

Authors

Claire, Michael Holtz, Ross Donaldson