Ischemic Colitis

Snapshot

• A 73-year-old woman presents with severe abdominal pain and a recent history of passing bloody stools. The pain began about 3 days ago and is more concentrated at the left side of the abdomen. Physical examination shows decreased-to-absent bowel sounds, abdominal distention, and diffuse tenderness to palpation over her abdomen. A barium-enema study is performed which shows “thumb-printing” of the colon. 

Introduction

• Clinical definition
  • medical condition characterized by inadequate blood supply to the large intestine leading to inflammation and injury of the colon
• Epidemiology
  • demographics
    • more common in the elderly population
    • most common form of bowel ischemia
  • risk factors 
    • aortoiliac surgery/instrumentation
    • myocardial infarction
    • hemodialysis
    • hypercoagulable states (e.g., hereditary thrombophilia)
• Pathogenesis
  • ischemic colitis is the result of blood flow reduction to the colon and is particularly prominent at the “watershed” areas of the colon where collateral blood flow is limited
    • the splenic flexure and rectosigmoid junction are particularly at risk for ischemia 
  • nonocclusive colonic ischemia
    • accounts for the mass majority of cases (95%)
    • typically transient hypoperfusion
    • examples include shock, systemic hypotension or atherosclerosis of SMA  
  • occlusive colonic ischemia
    • can be embolic (e.g., spontaneous or iatrogenic) or thrombotic secondary to atherosclerotic disease
  • mesenteric vein thrombosis
• extremely rare and usually involves the small intestine

Presentation

• Symptoms
  • mild cramping abdominal pain commonly involving the left side  
    • less severe compared to mesenteric ischemia
  • hematochezia
    • usually follows within 24 hours after abdominal pain
  • diarrhea
  • vomiting
• Physical exam
  • fever
  • abdominal tenderness
• weight loss

Imaging

• Abdominal radiograph
  • usually normal but may be useful in excluding other causes of abdominal pain
  • may also identify complications of mesenteric ischemia (e.g., necrosis)
• Computed tomography (CT) without oral contrast
  • best initial test  
  • may see bowel wall thickening in a segmental pattern (thumbprinting), bowel dilation, mesenteric stranding, or intestinal pneumatosis 
• Endoscopic evaluation
  • can be done via colonoscopy for flexible sigmoidoscopy
  • allows for biopsy of suspicious areas
• positive findings include edematous, friable mucosa, erythema, and interspersed pale areas 

Studies

• Laboratory studies
  • leukocytosis
  • elevated lactate
• metabolic acidosis

Differential

• Mesenteric ischemia 
  • differentiating factors
    • commonly presents with severe abdominal pain and does not accompany hematochezia
• Colonic malignancy 
  • differentiating factors
• will appear differently on endoscopy and abdominal CT

Treatment 

• Management approach
  • treatment is dependent on its etiology, severity, and the clinical setting  
• Mild colonic ischemia
  • supportive care
    • bowel rest and observation
    • nasogastric tube if ileus is present
    • monitor for persistent fever, leukocytosis, peritonitis, or other signs of clinical deterioration
  • most patients will recover within days
• Moderate colonic ischemia
  • antibiotics
  • antithrombotic therapy
    • indicated for patients with mesenteric venous thrombosis or thromboembolism
• Severe colonic ischemia
  • signs of peritonitis, pneumatosis on imaging, or gangrene on colonoscopy
  • exploratory laparotomy
    • inidicated in patients with signs of bowel ischemia
• resected of necrotic bowel if applicable

Complications

• Bowel necrosis
• Perforation
• Sepsis
• Death
• Stricture/obstruction