Colonic Obstruction

  • – Large bowel obstruction is approximately 3 to 4 times less likely than SBO
  • – Adenocarcinoma causes more than half of all cases of colonic obstruction
  • – 20% of CRC patients present with obstruction
  • – Most obstructing colon cancers occur distal to the splenic flexure

 

  •                                              Colonic Volvulus
    • – Colonic volvulus is the axial twisting of the colon on its vascular pedicle
    • – Typically, a closed-loop obstruction is produced that causes ischemia of the bowel wall due to twisting of the vascular pedicle and increased wall tension from colonic distention.
    • – The sigmoid colon and cecum are the most common sites of colonic volvulus
    • – The anatomic factors necessary for the development of volvulus
      • • Redundant segment of bowel that is freely movable within the peritoneal cavity
      • • Long movable mesocolon
      • • Close approximation of 2 points of fixation of the colon
  •                                                 Pathophysiology: 
  •                             In presence of competent ileocecal valve:
    • – The obstructed colon cannot decompress fluid and gas distally because of the blockage in the colon, and when the ileocecal valve is competent, neither can the colon decompress its contents proximally into the small intestine
    • – A closed-loop obstruction results, which ultimately leads to colonic ischemia and perforation
    • – Acute dilatation of the cecum to 10 cm suggests colonic wall ischemia, and a diameter greater than 13 cm implies imminent perforation
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  •                      
  •             Clinical Features
    • – Periumbilical / hypogastric pain
    • – Abdominal distention
    • – Severe unremitting pain suggests gangrenous bowel and mandates urgent laparotomy
    • – Diarrhea (reflecting the passage of liquid stool around an obstructing lesion) or Obstipation,depending upon the degree and location of the obstruction
    • – Acute abdominal distention : Colonic volvulus
  •                       Diagnosis:
  •     Radiologic feature of sigmoid volvulus:
    • – Distended ahaustral sigmoid loop
    • – Bent inner-tube appearance—the apex of which is directed toward the right shoulder
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  •                          
  •                     Features of Cecal Volvulus:
    • – Massively dilated cecum located in the epigastrium or left upper quadrant
    • – A distended kidney bean-shaped cecum
    • – Distended loops of small bowel suggesting SBO, and a single long air-fluid level present on upright or decubitus films
  •                    
  • – Patients with peritonitis should undergo resuscitation and urgent laparotomy without additional diagnostic procedures- In suspected sigmoid or cecal volvulus, a water-soluble contrast enema may be helpful by demonstrating a point of torsion (a mucosal spiral pattern or beak sign) while avoiding the risk of barium peritonitis in the case of unrecognized perforation
  • Colonoscopy a can be used to assist with diagnosis, but caution must be used with insufflation so as not to further compromise the already distended bowel

 

  • Treatment of Colonic Obstruction:

 

    • – Endoscopic balloon dilation of strictures in:
    •              • Diverticulitis
    •              • Anastomotic strictures
    •              • IBD
    • – Self-expanding metal stents
    • – SurgeryInitial management:
      • – Fluid and electrolyte resuscitation
      • – NG aspiration
      • – Urgent Laparotomy in case of peritonitis or strangulated obstruction

       

      For Benign and Malignant Colonic Strictures:

      •  – Endoscopic balloon dilation of strictures in:
      •              • Diverticulitis
      •              • Anastomotic strictures
      •              • IBD
      • – Self-expanding metal stents
      • – Surgery

       

                             For Volvulus:

    • – Decompression of a sigmoid volvulus by
    •           • Flexible or rigid sigmoidoscope
    •            • Placement of a rectal tube
    • – Endoscopic reduction of sigmoid volvulus
    • – Sigmoid resection with end colostomy and a Hartmann’s pouch or primary anastomosis for strangulated sigmoid volvulus
    • – Right hemicolectomy with primary ileocolic anastomosis for Cecal volvulus

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