II. Causes

  1. Roux-en-Y gastric bypass
    1. Intraabdominal Hernia near Gastric Bypass site with secondary ischemia and infarction of bowel

III. Epidemiology

  1. Occurs in up to 3% of retrocolic bypass procedures

IV. Pathophysiology

  1. Small Bowel trapped in Internal Hernia results in closed loop obstruction

V. Risk Factors

  1. Greatest post-surgical weight loss (exaggerates defects)
  2. Laparoscopic surgery (less adhesions)

VI. Types

  1. Peterson Defect (approximately 66% of cases)
    1. Occurs in the space between the mesentery and the overlying roux limb as it approaches the pouch
  2. Small Bowel anastomosis defect (approximately 33% of cases)
    1. Occurs in the space between the mesentary and the overlying Jejunostomy
    2. Higher risk of Small Bowel ischemia or infarction

VII. Signs: Presentation

  1. Most common in first 6-18 months post-operatively
  2. Presents with colicky Epigastric Pain that worsens with eating

VIII. Evaluation

  1. Requires urgent surgical Consultation

IX. Imaging: Abdominal CT with oral and IV contrast

  1. Positive findings are subtle
    1. Mesenteric edema
    2. Swirling mesenteric vessels
      1. Pathognomonic for Internal Hernia
      2. Represent bowel loops around the Internal Hernia site
  2. CT is only helpful if positive (often normal initially)
    1. Emergent surgery is indicated for a positive CT
  3. Negative result should not be considered reassuring
    1. Does not replace urgent Consultation with bariatric surgeon if Internal Hernia is suspected

X. Complications

  1. Critical Illness or death
  2. Short bowel syndrome (resection of necrotic Small Bowel)

XI. References

  1. Weinstock in Majoewsky (2012) EM:RAP 12(3): 3

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