Bowel Obstruction


  • Open vs Closed
  • Incomplete vs Complete
  • Extrinsic (tumor, volvulus, adhesions, hernias) vs Intramural (tumor, stricture, Crohn’s, ischemia) vs Intraluminal (constipation, FB, bezoar – tricho, phyto)
  • Small bowel vs Large bowel

Differential Diagnosis of a Small Bowel Obstruction

  • Adhesions
  • Hernias
  • Neoplasm (Adenocarcinoma, Carcinoid)
  • Inflammatory bowel disease, Volvulus, Intussusception, Gallstone ileus, Bezoars

Differential diagnosis of a large bowel obstruction (usually sigmoid)

  • Carcinoma
  • Diverticulitis
  • Volvulus
  • IBD, Radiation, Intussusception, Olgilvie’s, Paralytic ileus, Metabolic ileus, Drugs


  • Presentation: obstipation, nausea and vomitting, cramping, distension, typanism, dehydration, tinkling bowel sounds, pain, visible peristalsis
  • Last meal
  • B symptoms: fevers, night sweats, weight loss
  • PMHx – previous surgeries, diet (high fibre, high bulk = volvulus), inflammatory bowel disease, tumors, bleeding problems, hernias
  • Medications
  • Family history – cancer, bleeding
  • Social history– smoking, EtOH

Physical exam

  • Vitals (if dehydrated – tachycardia, postural hypotension, low urine output)
  • Inspection: distension, visible peristalsis
  • Percussion: tympanic, pain
  • Palpation: masses, distension, pain (complicated)
  • Auscultation: loud Borborygmus (tinkling), lack of bowel sounds


  • CBCD, lytes, BUN, Cr
  • Beta HCG
  • Amylase, Lipase
  • Low sodium
  • Low potassium
  • Low volume
  • WBC if strangulated
  • Metabolic alkalosis with vomiting (hypokalemic, hypochloremic)


  • Abdominal x-rays
    • Great Big FART
      • Gas pattern
      • Bowel wall air
      • Free air
      • Air fluid levels
      • Air in Rectum
      • Thickened bowel wall
    • 60% will be normal
    • upright chest x-ray or left lateral decubitus to rule out free air
    • No air in rectum and many air fluid levels
    • If ischemic look for free air, pneumatosis, thicked bowel wall, air in portal vein
    • No air in RLQ, bubble in LUQ – cecal volvulus
    • Omega or kidney bean in RLQ with bird’s beak – sigmoid volvulus
    • Double bubble – duodenal atresia
    • Air in biliary tree plus SBO – gallstone ileus
    • Cecum >12cm, Transverse colon >6cm, SB >5cm –> OR
  • Ultrasound – for closed loop
  • CT – for questionable patients
  • Contrast studies – enema, not from above!

Do not take to OR if:

  • Post-op
  • Carcinomatosis
  • Recurrent adhesive bowel obstruction
  • Post radiotherapy


  • Stabilize vitals, fluid and electrolyte resuscitation
  • NG tube
  • Foley catheter to monitor in/outs
  • Manage conservatively if partial – take to OR if does not resolve
  • If strangulated/complicated – to OR


  • NPO, ice chips
  • AAT
  • Vitals q2h
  • IV Ringer’s lactate bolus 500cc-2000cc then run at 150cc/hr
  • CBCD, lytes, BUN, Cr, amylase, lipase
  • Abdominal x-ray 3 views, repeat in 8 hrs
  • NG to gravity or low suction
  • Foley to urometer
  • Ins/Outs q1hr, call if <60cc over 2 hr
  • Flagyl 500mg IV on call to OR
  • Ancef 1g IV on call to OR

Leave a Comment