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

Management of Small Bowel Obstruction

Begin immediate conservative 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, 3

Initial Resuscitation and Assessment

Immediate Actions:

• Start IV crystalloid resuscitation immediately upon suspicion 3
• Insert nasogastric tube for gastric decompression and aspiration prevention 3, 4
• Place Foley catheter to monitor urine output and hydration status 3
• Maintain strict NPO status and administer antiemetics 3

Laboratory Evaluation:

• Obtain complete blood count, electrolytes, BUN/creatinine, lactate, C-reactive protein, and coagulation profile 2, 3
• Elevated lactate, leukocytosis with left shift, and elevated CRP indicate potential peritonitis or intestinal ischemia 2, 5

Physical Examination Focus:

• Assess for abdominal distension, abnormal bowel sounds, and peritoneal signs 2, 6
• Examine all hernial orifices and previous surgical scars 6
• Look for signs of shock: tachycardia, tachypnea, cold extremities, mottled skin, oliguria 6
• Fever, hypotension, diffuse abdominal pain, and peritonitis suggest strangulation 4

Diagnostic Imaging

CT Abdomen/Pelvis with IV Contrast is Mandatory:

• This is the imaging study of choice with >90% diagnostic accuracy and should be performed immediately 6, 3, 7
• CT identifies location, degree, and cause of obstruction 2, 6
• IV contrast is essential to evaluate for bowel ischemia 3
• Plain radiographs have only 50-60% sensitivity and cannot exclude the diagnosis—do not rely on them alone 3, 7

Alternative Imaging:

• MRI is a valid alternative in children and pregnant women with 95% sensitivity and 100% specificity 1, 2
• Ultrasound (including bedside) shows excellent diagnostic accuracy with positive likelihood ratio of 14.1 for formal scans 7

Decision Point: Surgery vs. Conservative Management

Immediate Surgical Intervention Required For:

• Signs of peritonitis, strangulation, or intestinal ischemia on clinical exam 1, 2, 3
• Free perforation with pneumoperitoneum and free fluid on CT 2, 6
• Closed-loop obstruction on imaging 6
• Severe sepsis or septic shock 2

Conservative Management Appropriate For:

• Hemodynamically stable patients without peritoneal signs 3
• No CT evidence of ischemia, perforation, or closed-loop obstruction 3
• This resolves 70-90% of adhesive small bowel obstructions 1, 2, 5

Conservative Management Protocol

Core Components:

• Continue IV fluids and correct electrolyte abnormalities, particularly hypokalemia 3
• Maintain nasogastric decompression (long intestinal tubes are more effective than nasogastric tubes but require endoscopic insertion) 1, 2
• Keep patient NPO 1, 2

Water-Soluble Contrast Administration:

• Administer 100 mL water-soluble contrast agent (Gastrografin) via nasogastric tube after adequate gastric decompression 1, 3
• Obtain abdominal X-ray at 8 and 24 hours after contrast administration 3
• Contrast reaching the colon within 4-24 hours predicts successful non-operative management with 90% resolution rate 2, 3
• This significantly reduces need for surgery, time to resolution, and length of stay 1, 2

Duration of Conservative Trial:

• A 72-hour period is considered safe and appropriate for non-operative management 1, 2, 3
• Surgery is indicated when conservative management fails after 72 hours 2

Surgical Approach When Indicated

Laparoscopic Adhesiolysis:

• Consider in hemodynamically stable patients with single adhesive band on CT, clear transition point, and minimal bowel distension 2, 3
• Reduces morbidity, in-hospital mortality, and surgical infections compared to open surgery 2
• Risk of iatrogenic bowel injury is 3-17.6% 2
• All enterotomies must be identified intraoperatively to avoid missed perforations 2

Open Laparotomy:

• Indicated for hemodynamically unstable patients, diffuse peritonitis, or very distended bowel loops 3
• Remains the surgical approach of choice in most cases requiring surgery 1, 6

Damage Control Surgery:

• For severe sepsis/septic shock: perform resection, staple intestinal ends, and temporary closure (laparostomy) 2

Special Considerations by Etiology

Adhesive Small Bowel Obstruction:

• Accounts for 65% of cases in adults 5
• Use adhesion barriers during surgery in young patients to reduce recurrence from 4.5% to 2.0% at 24 months 1, 2, 3
• Recurrence after non-operative management: 12% at 1 year, 20% at 5 years 1, 6
• Recurrence after operative management: 8% at 1 year, 16% at 5 years 1

Hernias:

• Attempt prompt manual reduction for complicated hernias 1
• Emergency surgery needed for unsuccessful reduction 1
• Same-admission elective surgery indicated for all patients with successful manual reduction 1

Malignant Bowel Obstruction:

• For left-sided obstructing colon cancer, self-expanding metallic stents are preferred over colostomy for palliation 1, 6
• Stents can serve as bridge to elective surgery with lower stoma rates 1
• For advanced disease, medical management is preferable: opioids, anticholinergics, corticosteroids, antiemetics, and octreotide 2, 6

Sigmoid Volvulus:

• Colonoscopy allows assessment of viability and detorsion with 70-95% success rate 1, 6
• If no necrosis, perform same-admission sigmoid colectomy with primary anastomosis 1
• Emergency surgery required for ischemic volvulus or failed detorsion 1

Virgin Abdomen (No Prior Surgery):

• Adhesions still occur from congenital bands or unrecognized inflammation 2, 3
• Non-operative management with water-soluble contrast is appropriate and effective 2
• In young females, examine for ovarian masses, endometriosis, or pelvic inflammatory disease 2

Critical Pitfalls to Avoid

• Do not delay surgical consultation when signs of ischemia are present—mortality increases to 25-30% with bowel necrosis/perforation 4, 5
• Do not rely on plain X-ray alone for diagnosis; proceed directly to CT 3, 7
• Do not miss examining all hernial orifices during physical examination 2, 6
• Do not attempt laparoscopy in patients with very distended bowel loops—this is a contraindication 2
• Do not forget to obtain biopsies for any colorectal stricture to exclude malignancy 2, 3

Complications and Monitoring

Common Complications:

• Dehydration with renal injury, electrolyte disturbances, malnutrition, and aspiration 2, 6
• Bowel perforation risk increases with prolonged distension and increased mural tension 5

Monitoring During Conservative Management:

• Serial abdominal examinations for development of peritoneal signs 4
• Monitor vital signs for signs of deterioration 6
• Repeat lactate if initially elevated 2
• Clinical or radiographic improvement should occur within 24 hours in most cases 8