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Intestinal Ischemia

Michael Koenig

Acute Mesenteric Ischemia

  • Sudden onset ↓ or absence of blood flow to the small intestines
  • Mesenteric Arterial Occlusion:
    • Arterial Embolism: Associated with cardiac arrhythmias (atrial fibrillation), valvular disease, endocarditis, ventricular aneurysm, aortic atherosclerosis, and aortic aneurysm
    • Arterial thrombosis: Most commonly from atherosclerotic disease; can also be 2/2 abdominal trauma, infection, or dissection
  • Venous thrombosis:
    • Associated w/ hypercoagulable states, malignancy, prior abdominal surgery, abdominal mass venous compression, intra-abdominal inflammatory processes
  • Non occlusive mesenteric ischemia:
    • Intestinal hypoperfusion and vasoconstriction; associated with decreased cardiac output, sepsis, vasopressor use


  • Early: Abdominal pain is most common symptom, abdominal distension
  • Abdominal tenderness is not prominent early (“pain out of proportion to the exam”)
  • Arterial occlusion: Sudden onset, severe periumbilical pain, nausea, and emesis
  • Venous thrombosis: More insidious onset abdominal pain, waxing and waning
  • Nonocclusive mesenteric ischemia: variable location and severity of abdominal pain; often overshadowed by a precipitating disorder
  • Late: As transmural bowel infarction develops, abdomen becomes distended, bowel sounds become absent, and peritoneal signs develop 


  • Type and Screen, Lactic acid, BMP, CBC
  • Imaging: KUB: Normal in > 25% of cases
  • Ileus w/ distended bowel loops, bowel wall thickening, ± pneumatosis intestinalis
  • Free intraperitoneal air immediate abdominal exploration
  • CT Angiography: no oral contrast, obscures mesenteric vessels, ↓ bowel wall enhancement
  • Focal or segmental bowel wall thickening, intestinal pneumatosis, portal vein gas, porto-mesenteric thrombosis, mesenteric arterial calcification, mesenteric artery occlusion


  • General: IVFs, NPO, hemodynamic monitoring and support (try to avoid vasoconstricting agents), anticoagulation, broad-spectrum antibiotics, pain control
  • If develops peritonitis or evidence of perforation on CT EGS consult for surgery
  • Mesenteric arterial embolism: Embolectomy vs. local infusion of thrombolytic agent
  • Mesenteric arterial thrombosis: Surgical revascularization vs. thrombolysis with endovascular angioplasty and stenting
  • Venous thrombosis: Anticoagulation; possible thrombolysis if persistent symptoms
  • Nonocclusive occlusion: Treat underlying cause, stop vasoconstriction meds, consider intra-arterial vasodilator infusion

Chronic Mesenteric Ischemia


  • ↓ blood flow to intestines, typically caused by atherosclerosis of mesenteric vessel
  • High-grade mesenteric vascular stenoses in at least two major vessels (celiac, SMA, or IMA) must be established


  • Recurrent dull, crampy, postprandial abdominal pain
  • Pts develop food aversion and often have associated weight loss


  • CTA abdomen/pelvis is preferred (>90% sensitivity and specificity)
  • Can also consider duplex U/S and gastric tonometry


  • Conservative management if asymptomatic: smoking cessation and secondary prevention to limit progression of atherosclerotic disease
  • Nutritional evaluation
  • Revascularization (open vs. endovascular) is indicated if symptoms are present
  • Mesenteric angioplasty and stenting is first-line therapy
  • Goal is to prevent future bowel infarction

Ischemic Colitis


  • Sudden, transient reduction in blood flow to colon
  • Typically at “watershed” areas, such as the splenic flexure and rectosigmoid junction
  • Most often nonocclusive (95% of cases) and affects older adults
  • Risk factors: ACS, hemodialysis, shock, aortoiliac instrumentation, cardiopulmonary bypass, extreme exercise (marathon running)


  • Rapid onset, mild cramping abdominal pain, associated with urge to defecate, hematochezia
  • Tenderness present (typically over left side)


  • Lactic acid (nonspecific but elevated), LDH, CPK, CBC (leukocytosis), BMP (metabolic acidosis)
  • KUB; if peritonitis or signs of severe ischemia → surgery 
  • CT A/P with IV contrast (and oral contrast if patient can tolerate)
  • Consider CTA A/P if suspicion for vascular occlusion
  • Colonoscopy confirms diagnosis. 
  • Edematous, friable mucosa; erythema; and interspersed pale areas; bluish hemorrhagic nodules representing submucosal bleeding
  • Segmental distribution, abrupt transition between injured and non-injured mucosa


General: IVFs, bowel rest, antibiotics (Zosyn vs CTX/flagyl)

Ischemic Colitis Management
Classification Management
Mild No risk factors (see below)

Supportive care and observation

Antibiotics can be stopped if no ulceration

Moderate 1-3 risk factors

Same as mild ischemia if no vascular occlusion

Systemic anticoagulation +/- vascular intervention if mesenteric occlusion

Severe > 3 risk factors, peritoneal signs, pneumatosis, pneumoperitoneum, gangrene or pancolonic ischemia on colonoscopy Consult EGS for abdominal exploration and segmental resection
Risk factors: male, SBP <90, HR >100, WBC>15k, Hgb <12, Na <136, BUN >20, LDH >350, isolated right-sided colonic involvement, abdominal pain with rectal bleeding

Last update: 2022-06-13 17:05:50