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

Upper gastrointestinal bleeding

• Peptic ulcer disease (most common cause)
  • Zollinger-Ellison syndrome
• Gastritis/esophagitis
• Gastric/esophageal varices
• Mallory-Weiss tear
• Malignancy
• Aortoenteric fisulta
• Boerhaave
• Dieulafoy's lesion
• Angiodysplasia
• Hemobilia
• Hemorrhagic gastritis, EtOH
• Celiac disease
• Dengue
• Other intrabdominal bleeds
  • Lower GI bleeding
  • Hemorrhagic pancreatitis
  • Splenic rupture
  • Subcapsular cavernous hemangiomas
  • Peliosis hepatis

Mimics of GI Bleeding

• Hemoptysis
• Vaginal/Urethra bleeding
• ENT bleeding
• Dietary (Iron, bismuth, beets)
• Swallowed maternal blood (in neonate)

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

Evaluation

Aortoenteric fistula and aortic dissection of the thoracic aorta. Arrow shows the flap in the aorta. Heterogeneity is blood in the stomach.

Aortoenteric fistula on CT showing extensive atherosclerosis of abdominal aorta and an infrarenal thrombosed aneurysm. In the extension of the thrombosed aneurysm, a soft tissue density is extending anteriorly (arrow), adherent to the duodenum and slightly compressing it.

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)
• Aortic ultrasound and FAST exam 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