What is the appropriate initial and subsequent management of an adult patient presenting with a small‑bowel obstruction?

Management of Small Bowel Obstruction

Immediate Resuscitation and Stabilization

Begin IV crystalloid resuscitation immediately upon suspicion of small bowel obstruction, insert a nasogastric tube for gastric decompression, place a Foley catheter to monitor urine output, maintain strict NPO status, and administer anti-emetics. 1

• Start aggressive fluid resuscitation with IV crystalloids to correct dehydration and electrolyte abnormalities, particularly hypokalemia 1, 2
• Insert nasogastric tube for gastric decompression and aspiration prevention, especially in patients with significant distension and vomiting 1, 2
• Place Foley catheter to monitor urine output and assess hydration status 1
• Obtain complete blood count, electrolytes, BUN/creatinine, lactate, CRP, liver function tests, and coagulation profile 1

Critical Diagnostic Step: CT Imaging

Proceed immediately to CT abdomen/pelvis with IV contrast—this is the gold standard with >90% diagnostic accuracy for small bowel obstruction and can identify life-threatening complications. 1, 3, 4

• CT with IV contrast has superior diagnostic accuracy compared to plain radiography (which has only 50-60% sensitivity) and should be the primary imaging modality 1, 5
• IV contrast is essential to evaluate for bowel ischemia and identify the underlying etiology 1
• No oral contrast is needed for high-grade obstruction as non-opacified fluid provides adequate intrinsic contrast 5

CT Findings Requiring Emergency Surgery

If any of the following CT findings are present, proceed immediately to surgical intervention: 1, 4

• Absent or abnormal bowel wall enhancement
• Intramural hyperdensity on non-contrast CT
• Bowel wall thickening with mesenteric edema
• Ascites with peritoneal signs
• Pneumatosis intestinalis or portal/mesenteric venous gas
• Closed loop obstruction with mesenteric haziness

Decision Point: Emergency Surgery vs. Conservative Management

Indications for Immediate Surgical Intervention

Operate immediately if the patient has signs of peritonitis, clinical deterioration (fever, leukocytosis, tachycardia, metabolic acidosis, continuous pain), or CT evidence of ischemia. 1, 6, 3

• Generalized peritonitis on physical examination 3
• Hemodynamic instability despite resuscitation 6
• CT findings suggesting ischemia or strangulation 1, 4
• Pneumoperitoneum with free fluid 1
• Clinical deterioration with fever, leukocytosis, tachycardia, or metabolic acidosis 3

Critical pitfall: Mortality increases from 10% to 25-30% with bowel necrosis/perforation, so do not delay surgical consultation when signs of ischemia are present. 5

Conservative Management Protocol

If the patient is hemodynamically stable with no signs of peritonitis, ischemia, or strangulation on clinical exam and CT imaging, proceed with conservative management. 1, 6

Initial Conservative Approach (First 48-72 Hours)

• Continue IV fluids and nasogastric decompression 1, 6
• Maintain bowel rest (NPO) 1
• Correct electrolyte abnormalities, particularly hypokalemia 1
• Provide adequate analgesia 2
• Conservative management successfully resolves 70-90% of adhesive small bowel obstruction cases 6

Water-Soluble Contrast Protocol

After adequate gastric decompression, administer 100 mL of water-soluble contrast via nasogastric tube and obtain abdominal X-rays at 8 and 24 hours. 1, 6

• If contrast reaches the colon within 4-24 hours, there is a 90% likelihood of successful non-operative resolution 6
• Patients passing contrast within 5 hours have particularly high resolution rates 6
• If no clinical improvement after 48-72 hours despite water-soluble contrast, proceed to surgical consultation 3

Surgical Approach When Indicated

Laparoscopic vs. Open Surgery

Open laparotomy is the surgical approach of choice in most small bowel obstruction cases requiring surgery. 6

• Mandatory open laparotomy for hemodynamically unstable patients, diffuse peritonitis, or very distended bowel loops 6
• Consider laparoscopic adhesiolysis only in hemodynamically stable patients with single adhesive band on CT, clear transition point, and minimal bowel distension 1, 6
• Laparoscopic approach has reduced morbidity and in-hospital mortality compared to open surgery in selected cases 6, 3

Intraoperative Considerations

• Consider adhesion barriers during surgery in young patients to reduce recurrence of adhesive small bowel obstruction 1
• Recurrence after operative management occurs in 8% at 1 year and 16% at 5 years 6

Special Considerations by Etiology

Adhesive Small Bowel Obstruction (55-75% of cases)

• History of previous abdominal surgeries has 85% sensitivity for adhesive small bowel obstruction 5
• Even remote surgical history can cause adhesions 5
• Most responsive to conservative management with water-soluble contrast protocol 6

Hernia-Related Obstruction (10-15% of cases)

• Examine all hernial orifices during physical examination 6
• Hernias typically require surgical intervention 1

Malignant Bowel Obstruction (5-10% of cases)

Surgery is primary treatment for malignant bowel obstruction in patients with years-to-months life expectancy; use medical management for advanced disease or poor condition. 6

• Any colorectal stricture requires endoscopic biopsies to exclude malignancy 1
• Medical management includes opioids, anticholinergics, corticosteroids, and antiemetics 6
• Use octreotide early due to high efficacy and tolerability 6
• Avoid prokinetic agents like metoclopramide in complete obstruction 6

Narcotic Bowel Syndrome

Specifically assess for opioid medication use, as narcotic bowel syndrome can mimic mechanical obstruction and lead to misdiagnosis. 5

• Chronic opioid use produces narcotic bowel syndrome with features of dysmotility 7
• Components of therapy include recognition, trusting therapeutic relationship, replacement with neuropathic pain drugs, and controlled opioid dose reduction 7
• Peripheral mu opioid antagonists (methylnaltrexone, alvimopan) may be helpful 7
• Opioids invalidate tests of small bowel motility and may increase risk of line infections in patients on long-term parenteral nutrition 7

Critical Pitfalls to Avoid

• Do not rely on plain X-ray alone for diagnosis—its sensitivity is only 50-60% with 20-30% inconclusive results; proceed to CT instead 1, 5
• Do not delay surgical consultation when signs of ischemia are present—mortality increases to 25% with ischemia 1
• Do not overlook bowel obstruction in elderly patients where pain may be less prominent 5
• Do not fail to correct electrolyte abnormalities before surgical intervention 5
• Do not mistake incomplete obstruction with watery diarrhea for gastroenteritis 5

Monitoring and Reassessment

• Reassess clinical status every 4-6 hours during conservative management 2
• Monitor for signs of clinical deterioration: worsening pain, fever, tachycardia, peritoneal signs 3
• If no improvement after 48-72 hours of conservative management, proceed to surgery 3
• Serial physical examinations are more reliable than repeat imaging in stable patients 2