Small bowel obstruction
Pearls
- SBO without hx of sx, no hernia = malignancy until proven otherwise
- "Never let the sun rise or set on a small bowel obstruction"
Causes
- Postoperative adhesions
- Malignancy
- Hernias
- Intraluminal strictures
- Crohn's disease
- Radiation therapy
- Mesenteric ischemia
- Trauma (particularly to the duodenum)
- Gallstone ileus
Clinical Manifestations
- Nausea/vomiting
- Seen more in proximal than distal obstruction
- Abdominal distention
- Seen more in distal than proximal obstruction
- Abdominal pain
- Typically crampy, periumbilical
- Paroxysms of pain occur q5min
- Inability to pass flatus
- Pts may pass flatus/stool initially
- Takes 12-24hrs for colon to empty
- Dehydration
- Anorexia
- Metabolic alkalosis
- Strangulation may occur
- Fever
- Leukocytosis
Laboratory Diagnosis
- CBC - evidence of strangulation?
- Chem - degree of dehydration, evidence of ischemia (acidosis)
- Lactate -Sensitive (90-100%), though not specific, marker of strangulation
Imaging
- Acute abdominal series
- Upright chest film: r/o free air
- Upright abd film: air-fluid levels
- Supine abd film: width of loops of bowel most visible (estimate of amount of distention)
- Presence of air in colon or rectum makes complete obstruction less likely (esp of symptoms > 24hr)
- If pt cannot be placed in upright position a left lateral decub abd film can substitute
- CT A/P with PO and IV contrast
- Consider if plain films are non-diagnostic
- Can show closed-loop obstruction, evidence of ischemia
Management
- IV fluid resuscitation with electrolyte repletion
- Assessment of need for operative vs nonoperative management
- Nonoperative Management
- Sometimes successful in patients with partial SBO (must rule-out strangulation first!)
- IV fluid resuscitation with electrolyte repletion
- NG tube
- 14 French
- Intermittent low wall suction
- Nasogastric fluid losses can be replaced w/ NS + KCL (30-40 meq)
- Contrast
- Both diagnostic and therapeutic (draws water into the bowel stimulating peristalsis)
- Associated with decreased hospital stay, more rapid resolution of symptoms
- If increasing pain, distention, or peristent high NGT output, consider operative intervention
- Repeat CT scan may be helpful to detect early signs of bowel ischemia
- Repeat plain films are not helpful (only detect perforation)
- Operative Management
- 25% of pts admitted for SBO require surgery
- Indicated for pts with:
- Complete SBO
- Closed-loop obstruction
- Fever, leukocytosis, peritonitis