What is the initial workup for a patient with abdominal pain and a history of bowel resection in the emergency department?

Emergency Department Workup for Abdominal Pain in Patients with History of Bowel Resection

Patients with abdominal pain and a history of bowel resection require immediate laboratory tests, imaging assessment, and consideration for surgical consultation due to their high risk of bowel obstruction and other post-surgical complications. 1, 2

Initial Assessment

• Evaluate vital signs immediately, with particular attention to tachycardia (≥110 beats/min), fever (≥38°C), hypotension, tachypnea, and hypoxia as these are alarm signs that may indicate serious complications 2
• Assess for persistent vomiting and nausea, which are alarming clinical signs suggesting potential internal hernia, volvulus, gastrointestinal stenosis, or bowel ischemia 1
• Evaluate for signs of intestinal bleeding such as hematemesis, melena, and hematochezia, which are predictors of intra-abdominal complications 1
• In the presence of respiratory distress and hypoxia, pulmonary embolism must be systematically excluded 1
• Even in the absence of fever, tachycardia (especially in patients taking beta blockers) warrants urgent evaluation 1

Laboratory Tests

• Complete blood count with differential to assess for leukocytosis, which may indicate infection or inflammation 1, 2
• Serum electrolytes to evaluate for derangements common in bowel obstruction 1, 2
• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) as inflammatory markers with higher sensitivity and specificity than white blood cell count 1, 2
• Liver enzymes and serum albumin to assess nutritional status and degree of inflammation 1
• Serum lactate levels to evaluate for potential bowel ischemia, though this may rise late in the disease process 1, 2
• Blood gas analysis to assess acid-base status 1
• Rule out infectious causes, especially Clostridium difficile, which can cause symptoms similar to bowel obstruction 1

Imaging Studies

• Contrast-enhanced computed tomography (CT) with oral and intravenous contrast is the preferred initial imaging method for evaluating acute abdominal pain in patients with prior bowel resection 2, 3
• Plain abdominal radiography can detect bowel dilatation or fluid levels suggestive of obstruction when CT is not immediately available, though it has limited diagnostic value 2, 3
• Bedside ultrasonography can be used to evaluate for free intraperitoneal fluid 2
• In pregnant women, ultrasonography and magnetic resonance imaging are preferred to limit radiation exposure 2

Surgical Evaluation

• If clinical suspicion is high and alarm signs are present (persistent pain, vomiting, tachycardia, fever), surgical consultation should not be delayed, even with negative radiological findings 1, 2
• Diagnostic laparoscopy has higher sensitivity and specificity than any radiological evaluation and should be considered when diagnosis remains unclear 2
• The combination of fever, tachycardia, and tachypnea are significant predictors of anastomotic leak or other serious complications requiring surgical intervention 1

Common Causes to Consider

• Adhesive small bowel obstruction (55-75% of small bowel obstruction cases) is the most common complication in patients with history of bowel resection 1
• Internal hernia, especially in patients with Roux-en-Y reconstructions 1
• Anastomotic stricture or leak 1
• Recurrent disease (particularly in patients with history of inflammatory bowel disease) 1
• Volvulus around adhesions or surgical sites 1

Management Approach

• Early administration of intravenous fluids for resuscitation in patients with signs of dehydration or sepsis 2
• Nasogastric tube decompression if bowel obstruction is suspected 1
• In the presence of infection or abscess, antimicrobial therapy should be started against Gram-negative/aerobic, Gram-positive, and anaerobic bacteria 2
• Consider early surgical consultation, as patients with prior bowel resection have higher risk of requiring operative intervention 1, 2

Pitfalls and Caveats

• Do not rely solely on normal CRP or white blood cell count to rule out serious pathology, as these may be normal in early stages of complications 1
• Avoid delaying surgical consultation in patients with persistent symptoms, even with equivocal imaging findings 1
• Be aware that patients with prior bowel resection may present with atypical symptoms due to altered anatomy 2
• Serum lactate levels should not be used alone to rule out internal herniation or bowel ischemia, as they may rise late in the disease process 1
• Clinical presentation can be non-specific; maintain high suspicion for complications in any patient with history of bowel resection presenting with abdominal pain 1