II. Epidemiology
- Accounts for 20-30% of Acute Mesenteric Ischemia
- Age: 70 years is mean age
III. Pathophysiology
- Decreased perfusion to splenic flexure and distal sigmoid colon (watershed areas)
- Results from hypoperfusion or shock state
- Low Cardiac Output (shock)
- Mesenteric arterial Vasoconstriction (severe and prolonged)
IV. Causes
- Septic Shock
- Myocardial Infarction or Myocardial Ischemia
- Congestive Heart Failure exacerbation
- Hypovolemia
- Vascular compression from intraabdominal compression
-
Bowel Obstruction with Strangulation
- Internal Hernia or closed loop obstruction
- Volvulus
V. Risk Factors
- Hospitalized patients
- Post-Surgical status
- Hemodialysis
- Medications
VI. Symptoms
- Gradual onset of symptoms over days in Nonocclusive Mesenteric Ischemia
- Contrast with sudden symptom onset of acute mesenteric Occlusion
- Abdominal Pain is absent in 25% of cases
VII. Signs
- Bleeding per Rectum is common (occult or grossly bloody stools)
VIII. Imaging
-
Abdominal CT or Abdominal MRI
- Bowel ischemia may be present
- Colonoscopy with biopsy (gold standard)
- Angiography
- May show arterial narrowing
- Abdominal Xray
- Listed for historical reasons only (all other advanced imaging is preferred)
- Early: Mild bowel dilation
- Late: Thumb printing, pneumatosis, portal venous gas
IX. Management
- See Mesenteric Ischemia
- Supportive care is paramount
- Fluid Resuscitation to reverse hemodynamic instability
- Avoid Vasopressors
- Avoid Vasoconstricting agents
-
Bowel infarction
- Anticoagulation or antiplatelet agents
- Vasodilation
- Targeted Papaverine infusion via angiography (Intervention Radiology)
- Risk of Hypotension if catheter migrates into aorta
- Targeted Papaverine infusion via angiography (Intervention Radiology)
- Surgery is only indicated if peritoneal signs are present
X. Prognosis: Outcomes
- Overall mortality is >50%
- Reversible ischemia in 44% of cases
- Persistent colitis in 19% of cases
- Ischemic stricture in 13% of cases
- Perforation or gangrene in 19% of cases
XI. References
- Fraboni (2012) Board Review Express, San Jose
- Kern and Gilley-Avramis (2022) Crit Dec Emerg Med 36(11) 21-8
- Mastoraki (2021) World J Gastrointest Pathophysiol 7(1): 125-30 [PubMed]