What is the management approach for a patient with a small bowel obstruction?

Management of Small Bowel Obstruction

Initial Assessment and Risk Stratification

Begin immediate non-operative management with IV crystalloid resuscitation, nasogastric decompression, bowel rest, and water-soluble contrast administration for all patients without signs of peritonitis, strangulation, or ischemia—this approach successfully resolves 70-90% of cases and should continue for up to 72 hours before considering surgery. 1, 2

Identify Patients Requiring Emergency Surgery

Perform focused physical examination looking for:

• Signs of peritonitis (diffuse tenderness, guarding, rebound) 1, 2
• Clinical deterioration markers: fever, hypotension, tachycardia, continuous (not colicky) pain 1, 3
• Examination of all hernia orifices and previous surgical scars 1, 2
• Abdominal distension (positive likelihood ratio 16.8) 2

Obtain laboratory tests immediately:

• Complete blood count (leukocytosis with left shift suggests ischemia) 2, 4
• Serum lactate (elevated levels indicate bowel ischemia) 2, 5
• C-reactive protein (elevation suggests peritonitis or ischemia) 2, 4
• Electrolytes, BUN/creatinine (assess dehydration severity) 2

Imaging Strategy

Order CT scan with IV contrast as the primary imaging modality—it has superior sensitivity and specificity compared to plain radiographs (which have only 60-70% sensitivity and should not be relied upon to exclude obstruction). 2, 5, 6, 7

CT scan provides critical information:

• Location and degree of obstruction 2, 5
• Identification of transition point (suggests single adhesive band amenable to laparoscopy) 5
• Signs of closed-loop obstruction or ischemia (requires immediate surgery) 2, 5
• Cause of obstruction (adhesions, hernia, malignancy) 2, 6

Alternative imaging: MRI is equally accurate (95% sensitivity, 100% specificity) for pregnant women and children 5, 8

Non-Operative Management Protocol

Core Components (Initiate Immediately)

• NPO status 2, 5
• Nasogastric tube decompression to prevent aspiration and reduce intraluminal pressure 2, 5, 3
• IV crystalloid resuscitation with aggressive fluid replacement (patients are typically severely dehydrated) 2, 5
• Electrolyte monitoring and correction (particularly potassium and chloride) 2, 5
• Foley catheter for strict intake/output monitoring 2

Water-Soluble Contrast Administration

Administer 100 mL of water-soluble contrast agent (Gastrografin) via nasogastric tube after adequate gastric decompression—this has both diagnostic and therapeutic value, significantly reducing need for surgery, time to resolution, and length of stay. 2, 5, 8

Diagnostic value: If contrast reaches the colon within 4-24 hours, there is 90% probability of successful non-operative resolution 2, 5

Therapeutic mechanism: The hyperosmolar contrast draws fluid into the bowel lumen, reducing edema and promoting passage 5

Monitoring During Non-Operative Management

Perform serial abdominal examinations every 4-6 hours looking for:

• Development of peritoneal signs 5
• Rising lactate levels (suggests evolving ischemia) 5
• Persistent fever or leukocytosis 1, 3
• Failure of clinical improvement after 48-72 hours 2, 5

Critical pitfall: Delaying surgery beyond 72 hours in patients with persistent obstruction increases morbidity and mortality 5

Indications for Surgical Intervention

Immediate Surgery Required

• Peritonitis (diffuse tenderness, guarding, rebound) 1, 2, 5
• Signs of strangulation or ischemia (fever, tachycardia, continuous pain, elevated lactate) 1, 2, 5
• Closed-loop obstruction on CT 2, 5
• Free perforation with pneumoperitoneum 5, 8
• Hemodynamic instability despite resuscitation 8

Delayed Surgery Indications

• Failure of non-operative management after 72 hours 1, 2, 5
• Failure of contrast to reach colon within 24 hours after administration 5
• Clinical deterioration during observation period 1, 3

Surgical Approach Selection

Laparoscopic Approach

Consider laparoscopy only for highly selected patients: hemodynamically stable, single adhesive band with clear transition point on CT, minimal bowel distension 5, 8

Benefits: Reduced morbidity, shorter hospital stay, lower infection rates compared to open surgery 5

Limitations and risks:

• Iatrogenic bowel injury risk 3-17.6% 5
• Higher bowel resection rates (53.5% vs 43.4% open) in some series 5
• Contraindicated with very distended bowel loops 5
• High conversion rates to open surgery 5

Open Laparotomy

Remains the surgical approach of choice for most cases requiring surgery, particularly:

• Hemodynamically unstable patients 5, 8
• Diffuse peritonitis 5
• Significantly distended bowel 5
• Multiple adhesions suspected 5

Adhesion Barrier Use

Apply adhesion barriers during surgery in young patients—this reduces recurrence from 4.5% to 2.0% at 24 months, which is particularly important given their higher lifetime risk for recurrent episodes. 1, 5

Special Considerations

Patients Without Prior Abdominal Surgery

Adhesions remain common even in "virgin abdomen" from congenital bands or unrecognized inflammation—proceed with same non-operative management protocol including water-soluble contrast. 5

Malignant Bowel Obstruction

For patients with known advanced malignancy:

• Surgery is appropriate for patients with years-to-months life expectancy 5
• Medical management preferred for poor performance status: opioids, anticholinergics, corticosteroids, antiemetics 5
• Octreotide highly recommended early due to high efficacy and tolerability 5
• Self-expanding metallic stents for left-sided obstructing colon cancer (preferred over colostomy for palliation) 5, 8

Inflammatory Bowel Disease

• Free perforation requires emergency surgery 5
• Endoscopic balloon dilation has 89-92% technical success rate for Crohn's strictures 5
• Biopsy all colorectal strictures to exclude malignancy 5

Chronic Small Intestinal Dysmotility

Distinguish from mechanical obstruction—look for absence of transition point on CT, history of multiple failed surgeries, encasement in fibrous tissue 1

Management differs significantly:

• Avoid unnecessary surgery (worsens dysmotility) 1
• Consider narcotic bowel syndrome if long-term opioid use 1
• Gradual supervised opioid withdrawal may be necessary 1
• Nutritional support escalation: oral supplements → enteral feeding → parenteral nutrition 1

Complications and Recurrence

Common Complications to Monitor

• Dehydration with acute kidney injury 2, 5, 8
• Electrolyte disturbances (hypokalemia, hypochloremia, metabolic alkalosis) 2, 5
• Aspiration pneumonia 2, 5
• Malnutrition 2, 5

Recurrence Rates

After non-operative management: 12% readmission at 1 year, 20% at 5 years 5, 8

After operative management: 8% recurrence at 1 year, 16% at 5 years 5

Highest risk population: Young patients with multiple prior surgeries 1, 5

Key Clinical Pitfalls

• Do not rely on plain radiographs alone—they miss 20-52% of cases and cannot exclude obstruction 6, 7
• Do not delay CT scan when clinical-radiographic findings are inconclusive 6
• Do not continue non-operative management beyond 72 hours without clear clinical improvement 2, 5
• Do not miss signs of strangulation—continuous (not colicky) pain, fever, tachycardia, and elevated lactate require immediate surgery 1, 2, 3
• Do not attempt laparoscopy in patients with very distended bowel or hemodynamic instability 5
• Do not overlook opioid-induced bowel dysfunction or narcotic bowel syndrome in patients with chronic pain 1