Bowel Obstruction Approach

– History –

1. Is it obstruction or not?

  • Cardinal features: N\V, abdominal pain, distension, decreased flatus, constipation\obstipation

2. What’s the likely level of obstruction?

Proximal Distal
Cramping pain (periumbilical)

Early vomiting (may be bilious)

Minimal distension

May still have bowel movement\passing flatus distal to obstruction

Cramping pain (lower abdomen)

Late\absent vomiting (may be fecal)

Large distension

Early constipation\obstipation

3. What’s the probable cause:

  • Intraluminal:
    • Fecal impaction, gallstone ileus, foreign body, bezoar, worm ball (Ascaris)
  • Intramural:
    • Neoplasm (benign\malignant), intussusception, inflammatory, ischemia
  • Extrinsic:
    • Adhesions, hernia, volvulus\malrotation, intra-abdominal tumors (ovarian masses, mesenteric cysts, pancreatic cysts, GIST), tumor cell deposits in mesentery, annular pancreas, intra-abdominal abscess or hematoma

4. Partial or complete?

  • Still passing stool\flatus -> partial obstruction
  • No bowel movement > 24 hrs \ obstipation -> complete obstruction

5, Simple or complicated?

  • No peritoneal signs = simple obstruction
  • Peritoneal signs, ischemia, gangrene, perforation = complicated obstruction

6. Any systemic manifestations caused by the obstruction?

  • Dehydration, electrolyte disturbances, hemodynamic instability, renal impairment


Important points in PMHx:

  • Diseases: malignancy, atherosclerotic ds, prev MI\stroke, arrhythmia, IBD, diverticulitis, chronic biliary colic, hx of hernia
  • Review medications
  • Previous abdominal operations


– Physical Exam –

  1. Vital signs: hemodynamic stability (tachycardic, hypotensive), fever
  2. Abdominal exam:
    • Inspection: scars, distention, obv masses, hernia
    • Palpation: tenderness, guarding, masses, hernia
    • Percussion: tympanic
    • Bowel sounds: hyperactive -> hypoactive\absent
  3. PR exam:
    • Empty rectal vault?
    • Fecal impaction?
    • Pelvic masses?
    • + FOBT -> strangulation, ca, inflammation


– Investigations –

  1. Labs:
    • CBC: leukocytosis, hgb\hct (high if dehydrated, low if anemic)
    • Electrolytes: hypokalemia
    • Renal function: BUN, Cr (high if dehydrated)
    • Amylase
    • U\A
  2. Imaging:
    • Plain films: initial
    • Barium: for LBO
    • CT: for SBO


– Management –

  • If partial, simple obstruction -> conservative therapy:
    • NPO
    • IV hydration
    • Correct electrolyte imbalances
    • NGT decompression
    • Foley’s cath to monitor output
  • If not improving or worsening of partial obstruction w\ conservative therapy, signs of peritonitis, hemodynamic instability -> OR


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