Aortoenteric fisulta

Background

• Fistula formed between aorta and intestines
  • Can be primary or secondary (often due to AAA repair)
  • Can form fistula anytime within life of AAA graft repair
    • Higher risk with recent graft placement
• Involves the duodenum (ADF) in most cases
• Incidence of primary aortoenteric fistulas is estimated to be about 0.007 per million while secondary aortoenteric fistulas is about 0.6-2%
• Mortality of 100% if left untreated

Clinical Features

• Classic triad: abdominal pain, GI bleeding and pulsatile abdominal mass
  • Present in 23% of patients
• Low grade fever
• Abdominal pain
• Back pain
• History of AAA graft
• BRBPR or melena
• Herald bleed - initial melena or hematochezia with few hemodynamic changes; then followed by severe bleed

Differential Diagnosis

Undifferentiated lower gastrointestinal bleeding

• Upper GI Bleeding
• Diverticular disease
  • Diverticulosis
  • Diverticulitis
• Vascular ectasia / angiodysplasia
• Inflammatory bowel disease
• Infectious colitis
• Mesenteric Ischemia / ischemic colitis
• Meckel's diverticulum
• Colorectal cancer / polyps
• Hemorrhoids
  • Internal hemorrhoid
  • External hemorrhoid
• Aortoenteric fistula
  • Nearly 100% mortality if untreated
  • Consider in patients with gastrointestinal bleeding and known abdominal aortic aneurysms or aortic grafts
• Rectal foreign body
• Rectal ulcer (HIV, Syphilis, STI)
• Anal fissure

Diagnosis

If suspicion high, involve vascular surgery early

• CBC
• Chem 10
• Type and Cross
• PT/INR/PTT
• Blood culture if fever - high risk for infections with secondary fistulas (ie grafts)
• Ultrasound: Aorta and Ultrasound: FAST to assess for AAA and Free Fluid
• CXR for pre-op, if patient stable
• ECG for pre-op
• CTA of abdomen/pelvis, highly sensitive, if patient stable
• Patient may need gastroduodenal endoscopy

Management

• Fluid resuscitation
• Transfuse pRBCs as needed
• Surgical Intervention
  • Transfer if not available

Disposition

• Admission