Snapshot A 69-year-old female presents to the emergency room for bright red blood per rectum for the past 2 hours. She noticed some blood in her stool shortly after experiencing some abdominal pain. The pain is reported as dull, achy, 5/10, and concentrated at the left lower quadrant. Her past medical history is significant for hypertension and a past myocardial infarction (MI). 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) ETIOLOGY 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 or systemic hypotension 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 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) angiography 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 Diagnostic testing diagnostic approach diagnosis is often based on clinical presentation and confirmed via endoscopy 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