Nonocclusive Mesenteric Ischemia

Aka: Nonocclusive Mesenteric Ischemia, NOMI

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II. Epidemiology

  1. Accounts for 20-30% of Acute Mesenteric Ischemia
  2. Age: 70 years is mean age

III. Pathophysiology

  1. Decreased perfusion to splenic flexure and distal sigmoid colon (watershed areas)
  2. Results from hypoperfusion or shock state
    1. Low Cardiac Output (shock)
    2. Mesenteric arterial Vasoconstriction (severe and prolonged)

IV. Causes

  1. Septic Shock
  2. Myocardial Infarction or Myocardial Ischemia
  3. Congestive Heart Failure exacerbation
  4. Hypovolemia
  5. Vascular compression from intraabdominal compression
  6. Bowel Obstruction with Strangulation
    1. Internal Hernia or closed loop obstruction
    2. Volvulus

V. Risk Factors

  1. Hospitalized patients
  2. Post-Surgical status
  3. Hemodialysis
  4. Medications
    1. Vasopressors
    2. Digitalis

VI. Symptoms

  1. Gradual onset of symptoms over days in Nonocclusive Mesenteric Ischemia
    1. Contrast with sudden symptom onset of acute mesenteric Occlusion
  2. Abdominal Pain is absent in 25% of cases

VII. Signs

  1. Bleeding per Rectum is common (occult or grossly bloody stools)

VIII. Imaging

  1. Abdominal CT or Abdominal MRI
    1. Bowel ischemia may be present
  2. Colonoscopy with biopsy (gold standard)
  3. Angiography
    1. May show arterial narrowing
  4. Abdominal Xray
    1. Listed for historical reasons only (all other advanced imaging is preferred)
    2. Early: Mild bowel dilation
    3. Late: Thumb printing, pneumatosis, portal venous gas

IX. Management

  1. See Mesenteric Ischemia
  2. Supportive care is paramount
    1. Fluid Resuscitation to reverse hemodynamic instability
    2. Avoid Vasopressors
    3. Avoid Vasoconstricting agents
  3. Bowel infarction
    1. Anticoagulation or antiplatelet agents
    2. Vasodilation
      1. Targeted Papaverine infusion via angiography (Intervention Radiology)
        1. Risk of Hypotension if catheter migrates into aorta
    3. Surgery is only indicated if peritoneal signs are present

X. Prognosis: Outcomes

  1. Overall mortality is >50%
  2. Reversible ischemia in 44% of cases
  3. Persistent colitis in 19% of cases
  4. Ischemic stricture in 13% of cases
  5. Perforation or gangrene in 19% of cases

XI. References

  1. Fraboni (2012) Board Review Express, San Jose
  2. Kern and Gilley-Avramis (2022) Crit Dec Emerg Med 36(11) 21-8
  3. Mastoraki (2021) World J Gastrointest Pathophysiol 7(1): 125-30 [PubMed]

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