The American College of Gastroenterology published an excellent guideline on the management of Colon Ischemia in December 2014. This important topic was summarized by Utah Gastroenterology. For detailed information, please review the excellent guideline paper.

Abbreviations:

• AMI – acute mesenteric ischemia
• IRCI – isolated right colon ischemia
• SMA – superior mesenteric artery
• IMA – inferior mesenteric artery

Colonic Ischemia Recommendations and Best Practice Summary Statements

Clinical Presentation

• The diagnosis of CI is usually established in the presence of symptoms including sudden cramping, mild, abdominal pain; an urgent desire to defecate; and passage within 24 h of bright red or maroon blood or bloody diarrhea.
• A diagnosis of non-isolated right colon ischemia (non-IRCI) should be considered when patients present with hematochezia.

Imaging of CI

• CT with intravenous and oral contrast should be the first imaging modality of choice for patients with suspected CI to assess the distribution and phase of colitis.
• The diagnosis of CI can be suggested based on CT findings (e.g., bowel wall thickening, edema, thumbprinting).
  Multiphasic CTA should be performed on any patient with suspected IRCI or in any patient in whom the possibility of acute mesenteric ischemia (AMI) cannot be excluded.
• CT or MRI findings of colonic pneumatosis and porto-mesenteric venous gas can be used to predict the presence of transmural colonic infarction.
• In a patient in whom the presentation of CI may be a heralding sign of acute mesenteric ischemia (AMI) (e.g., isolated right colon ischemia (IRCI), severe pain without bleeding, atrial fibrillation), and the multiphasic CT is negative for vascular occlusive disease, traditional splanchnic angiography should be considered for further assessment.

Colonoscopy in the Diagnosis of CI

• Early colonoscopy (within 48 h of presentation) should be performed in suspected CI to confirm the diagnosis.
• When performing colonoscopy on a patient with suspected CI, the colon should be insufflated minimally.
• In patients with severe CI, CT should be used to evaluate the distribution of disease. Limited colonoscopy is appropriate to confirm the nature of the CT abnormality. Colonoscopy should be halted at the distal most extent of the disease.
• Biopsies of the colonic mucosa should be obtained except in cases of gangrene.
• Colonoscopy should not be performed in patients who have signs of acute peritonitis or evidence of irreversible ischemic damage (i.e., gangrene and pneumatosis).

Severity and Treatment of CI

• Most cases of CI resolve spontaneously and do not require specific therapy.
• Surgical intervention should be considered in the presence of CI accompanied by hypotension, tachycardia, and abdominal pain without rectal bleeding; for IRCI and pan-colonic CI; and in the presence of gangrene.
• Antimicrobial therapy should be considered for patients with moderate or severe disease.

Risk Factors

• Comorbid cardiovascular disease and diabetes mellitus should increase consideration of CI in patients with typical clinical features.
• A history of IBS and constipation should be sought in patients suspected to have CI.
• Selective cardiology consultation is justified in patients with CI, particularly if a cardiac source of embolism is suspected.
• Chronic kidney disease is associated with increased mortality from CI.
• Evaluation for thrombophilia should be considered in young patients with CI and all patients with recurrent CI.
• Surgical procedures in which the inferior mesenteric artery (IMA) has been sacrificed, such as abdominal aortic aneurysm repair and other abdominal operations, should increase consideration of CI in patients with typical clinical features.
• In patients suspected of having CI, a history of medication and drug use is important, especially constipation-inducing medications, immunomodulators, and illicit drugs.

Clinical Presentation

• IRCI is associated with higher mortality rates compared with other patterns of CI.

Laboratory Tests in CI

• Laboratory testing should be considered to help predict CI severity.
• Decreased hemoglobin levels, low serum albumin, and the presence of metabolic acidosis can be used to predict severity of CI.

Severity and Treatment of CI

• When considering mortality risk for patients undergoing surgical intervention for acute CI, the Ischemic Colitis Mortality Risk (ICMR) factors should be utilized.

Detailed Data Summary 

1.Risk factors

• Comorbid cardiovascular disease and diabetes mellitus should increase consideration of CI in patients with typical clinical features.
• A history of irritable bowel syndrome (IBS) and constipation should be sought in patients suspected to have CI.
• Selective cardiology consultation is justified in patients with CI, particularly if a cardiac source of embolism is suspected.
• Chronic kidney disease and chronic obstructive pulmonary disease are associated with increased mortality from CI.
• Evaluation for thrombophilia should be considered in young patients with CI and in all patients with recurrent CI.
• Surgical procedures in which the inferior mesenteric artery (IMA) has been sacrificed, such as abdominal aortic aneurysm repair and other abdominal operations, should increase consideration of CI in patients with typical clinical features.
• In patients suspected of having CI, a history of medication and drug use should be sought, especially constipation- inducing medications, immunomodulators, and illicit drugs.

2. Medical conditions and surgical history independently associated with colon ischemia in multivariate analyses of case–control studies

• Atherosclerosis
• Atrial fibrillation
• Chronic obstructive pulmonary disease
• Congestive heart failure
• Diarrhea
• Irritable bowel syndrome
• Diabetes
• Dyslipidemia
• Rheumatoid arthritis
• Systemic rheumatologic disorders

3a. Drugs proposed to predispose to CI and postulated pathogenesis  (moderate evidence)

• Constipation-inducing drugs (Predicted CI in patients with abdominal pain)
  
  • All drugs: C-CS; increased risk 0.68 (0.62–1.27)
    
  • Opioids: C-CS; increased risk 1.96 (1.43–2.67)
    
  • Nonopioids: C-CS; increased risk 1.75 (1.25–2.44)
    • Reduced blood flow, increased intraluminal pressure

• Immunomodulator drugs
  • Antitumor necrosis factor-α inhibitors for rheumatoid arthritis
  • Type 1 interferon-α for hepatitis C
  • Type 1 interferon-β for multiple sclerosis)
    • Cytokines affecting thrombogenesis

4. Clinical Presentation

• The diagnosis of CI is usually established because of symptoms including sudden cramping, mild, abdominal pain; an urgent desire to defecate; and passage within 24 h of bright red or maroon blood per rectum or bloody diarrhea.
• A diagnosis of non-IRCI should be considered when patients present with hematochezia.
• CI isolated to the right colon (IRCI) is associated with higher mortality rates compared with other patterns of CI.

5. Laboratory Testing

• Laboratory testing should be considered to help predict CI severity.
• Decreased hemoglobin levels, low serum albumin, and the presence of metabolic acidosis can be used to predict severity of CI.
• Recommended initial serology and stool studies for suspected colon ischemia (CI):
  • Blood tests
    • Albumin
    • Amylase
    • Complete blood count
    • Comprehensive electrolyte panel
    • Creatine kinase (CK)
    • Lactate
    • Lactate dehydrogenase (LDH)
  • Stool tests
    • Clostridium difficile toxin assay
    • Culture
    • Ova and parasite

6. Imaging of CI

• CT with intravenous and oral contrast should be ordered as the imaging modality of choice for patients with suspected CI, to assess the distribution and phase of colitis.
• The diagnosis of CI can be suggested based on CT findings (e.g., bowel wall thickening, edema, and thumbprinting)
• Multiphasic CT angiography (CTA) should be performed on any patient with suspected IRCI or in any patient in whom the possibility of AMI cannot be excluded.
• CT or magnetic resonance imaging (MRI) findings of colonic pneumatosis and portomesenteric venous gas can be used to predict the presence of transmural colonic infarction.
• In a patient in whom the presentation of CI may be a heralding sign of acute mesenteric ischemia (AMI; e.g., IRCI, severe pain without bleeding, and atrial fibrillation), and the multiphasic CT is negative for vascular occlusive disease, traditional splanchnic angiography should be considered for further assessment.

7. Classification of disease severity and management

• Mild
  • Typical symptoms of CI with a segmental colitis not isolated to the right colon and with none of the commonly associated risk factors for poorer outcome that are seen in moderate disease.
    • Observation
    • Supportive care
• Moderate
  • Any patient with CI and up to three of the following factors:
    • Male gender
    • Hypotension (systolic blood pressure <90mmHg)
    • Tachycardia (heart rate >100beats/min)
    • Abdominal pain without rectal bleeding
    • BUN >20mg/dl
    • Hgb <12g/dl
    • LDH >350U/l
    • Serum sodium <136mEq/l (mmol/l)
    • WBC >15 cells/cmm (×109/l)
    • Colonic mucosal ulceration identified colonoscopically
      • Correction of cardiovascular abnormalities (e.g., volume replacement)
      • Broad-spectrum antibiotic therapy
      • Surgical consultation
• Severe
  • Any patient with CI and more than three of the criteria for moderate disease or any of the following:
    • Correction of cardiovascular abnormalities (e.g., volume replacement)
    • Broad-spectrum antibiotic therapy
    • Peritoneal signs on physical examination
    • Pneumatosis or portal venous gas on radiologic imaging
    • Gangrene on colonoscopic examination
    • Pancolonic distribution or IRCI on imaging or colonoscopy
      • Emergent surgical consultation (treatment is likely to be surgical)
      • Transfer to intensive care unit
      • Correction of cardiovascular abnormalities (e.g., volume replacement)
      • Broad-spectrum antibiotic therapy

8. Predictors of disease severity (factors from multiple studies that are significantly associated with the requirement for surgery and/or mortality)

• Epidemiologic factors
  • Antibiotic treatment
  • Chronic obstructive pulmonary disease
  • Chronic kidney disease
  • Hepatitis C positivity
  • History of cancer
  • Male gender
  • Warfarin use
• Presentation of disease
  • Abdominal pain without rectal bleeding
  • Nonbloody diarrhea
  • Peritoneal signs
  • Symptom onset after admission
• Vital signs
  • Pulse >90-100beats/min
  • Systolic blood pressure <90mmHg
• Serology
  • Hemoglobin <12mg/dl
  • Na <136mEq/l (mmol/l)
  • LDH >450U/l
  • BUN >28.0 mg/dl
• Colonoscopic finding
  • Ulceration
  • Distribution of disease
  • Bilateral or right-side disease distribution
  • Isolated right colon involvement

9. Colonoscopy in the diagnosis of CI

• Early colonoscopy (within 48 h of presentation) should be performed in suspected CI cases to confirm the diagnosis.
• When performing colonoscopy on a patient with suspected CI, the colon should be insufflated minimally.
• In patients with severe CI, CT should be used to evaluate the distribution of disease. Limited colonoscopy is appropriate to confirm the nature of the CT abnormality. The endoscopic procedure should be stopped at the distal-most extent of the disease.
• Biopsies of the colonic mucosa should be obtained except in cases of gangrene.
• Colonoscopy should not be performed in patients who have signs of acute peritonitis or evidence of irreversible ischemic damage.

10. Severity and treatment CI

• Most cases of CI resolve spontaneously and do not require specific therapy.
• Surgical intervention should be considered in the presence of CI accompanied by hypotension, tachycardia, and abdominal pain without rectal bleeding; for IRCI and pancolonic CI; and in the presence of gangrene.
• Antimicrobial therapy should be considered for patients with moderate or severe disease.
• When considering the mortality risk for patients undergoing surgical intervention for acute CI, Ischemic Colitis Mortality Risk (ICMR) factors should be utilized.

11. Indications for surgery in colonic ischemia

• Acute indications
  • Peritoneal signs
  • Massive bleeding
  • Universal fulminant colitis with or without toxic megacolon
  • Portal venous gas and/or pneumatosis intestinalis on imaging
  • Deteriorating clinical condition
• Subacute indications
  • Failure of an acute segmental ischemic colitis to respond to treatment within 2–3 weeks with continued symptoms or a protein-losing colopathy
  • Apparent healing but with recurrent bouts of sepsis
• Chronic indications
  • Symptomatic colon stricture
  • Symptomatic segmental ischemic colitis

12. Risk factors for perioperative mortality

• Low output heart failure (e.g., cardiac ejection fraction <20% on echocardiogram)
• Acute kidney injury
• Subtotal or total colectomy
• Lactate >2.5mmol/l
• Pre- and intraoperative catecholamine administration
  • Risk factors = Mortality
    • 0 = 10.5%
    • 1 = 28.9%
    • 2 = 37.1%
    • 3 = 50.0%
    • 4 = 76.7%
    • 5 = 100.0%

ACG Clinical Guideline: Epidemiology, Risk Factors, Patterns of Presentation, Diagnosis, and Management of Colon Ischemia (CI)

Am J Gastroenterol 2015; 110:18–44

http://gi.org
http://gi.org/clinical-guidelines/
http://gi.org/clinical-guidelines/clinical-guidelines-sortable-list/
http://gi.org/guideline/epidemiology-risk-factors-patterns-of-presentation-diagnosis-and-management-of-colon-ischemia/
http://gi.org/wp-content/uploads/2015/01/ACG_Guideline_Colon-Ischemia_January_2015.pdf