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

1. Postoperative adhesions
2. Malignancy
3. Hernias�
4. Intraluminal strictures�
   1. Crohn's disease
   2. Radiation therapy
   3. Mesenteric ischemia
5. Trauma (particularly to the duodenum)�
6. 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

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