Colonic Volvulus


Sigmoid Volvulus

  1. Pathogenesis
    • accounts for 60% - 80% of colonic volvuli
    • overall, colonic volvuli account for 10% of colon obstructions in the U.S.
    • usually occurs in older patients or patients with an underlying neurologic or psychiatric disorder
    • most prominent association is chronic constipation, which leads to lengthening of the colon
    • worldwide, sigmoid volvulus has been associated with a high-fiber diet
    • a redundant sigmoid colon with a narrow-based mesentery is the requisite anatomic factor for sigmoid volvulus
    • colonic dysmotility may also predispose to torsion of the sigmoid colon

  2. Clinical Manifestations
    • may present with acute or subacute obstruction
    • usually presents with cramping abdominal pain, distention, and obstipation
    • physical exam is remarkable for a distended and tympanitic abdomen
    • abdominal tenderness, fever, and an elevated WBC suggest gangrenous bowel

  3. Diagnosis
    1. Abdominal X-Rays
      • plain films may reveal a dilated colon pointing towards the right upper quadrant (‘bent inner tube’ sign)
      • however, plain films are diagnostic of sigmoid volvulus in only 60% of cases
      • pneumatosis suggests impending bowel perforation

      Sigmoid Volvulus - Bent Inner Tube Sign
    2. CT Scan
      • highly accurate in establishing the diagnosis of sigmoid volvulus
      • can also rule out other causes of colonic obstruction
      • characteristic findings include a whirl pattern caused by the twisting of the sigmoid colon around its mesentery, and a bird-beak appearance of its afferent and efferent segments

      Sigmoid Volvulus - Whirl sign on CT Scan
      'Whirl' Sign

    3. Contrast Studies
      • in equivocal cases, a limited barium enema will show the barium ending sharply at the point of torsion (‘bird’s beak’ deformity)
      • barium studies should not be done if gangrene is suspected

      Sigmoid Volvulus - Birds Beak Sign
      'Bird's Beak' Sign

  4. Treatment
    1. No Peritonitis
      1. Sigmoidoscopic Decompression
        • proctoscopy or sigmoidoscopy will usually reach the point of obstruction and untwist the colon
        • a soft rectal tube is then passed through the scope and left in place
        • endoscopy also allows assessment of bowel mucosal viability

      2. Delayed Colon Resection
        • recurrence following nonoperative decompression is approximately 50% - 70%
        • during the initial admission, the patient should undergo a standard bowel prep and colonoscopy to rule out malignancy in the colon
        • open or laparoscopic sigmoid colectomy with primary anastomosis is the preferred definitive procedure
        • sigmoidopexy has a high rate of recurrence and should not be done

    2. Peritonitis
      • emergent laparotomy is required
      • sigmoid resection, end colostomy, and a Hartmann’s pouch is the standard operative approach
      • to prevent reperfusion injury, gangrenous bowel should not be detorsed
      • if the patient is hemodynamically stable and has adequate nutrition, a primary anastomosis can be considered
      • patients with a gangrenous colon have a mortality rate of 50% to 70%

Cecal Volvulus

  1. Pathogenesis
    • accounts for 15% to 30% of colonic volvuli
    • etiology is lack of fixation of the cecum and ascending colon to the retroperitoneum and lateral abdominal wall
    • 90% of patients have an axial twist of the terminal ileum and proximal colon; 10% have a cephalad fold of the cecum across the ascending colon (cecal bascule)

    Cecal Volvulus - Axial Twist and Cecal Bascule
    (L) Axial Twist Volvulus                 (R) Cecal Bascule

  2. Clinical Manifestations
    • presents as a small bowel obstruction (distention, crampy abdominal pain, nausea, vomiting)
    • patients may present with intermittent subacute episodes or with an acute abdomen

  3. Diagnosis
    1. Abdominal X-Rays
      • plain abdominal films typically show small bowel dilatation with air/fluid levels
      • in 25% of cases, a ‘coffee-bean'-shaped cecum projects from the right lower quadrant into the left upper quadrant

      Cecal Volvulus - Abdominal X-ray
    2. CT Scan
      • in patients with axial torsion, the ‘whirl sign’ is diagnostic (twisting of the mesentery around the ileocolic vessels
      • in a cecal bascule, the CT will show the cecum folding upward, resulting in obstruction without the axial twist

      Cecal Volvulus CT Scan - Axial Twist and Cecal Bascule
      (L) Axial Torsion 'Whirl' Sign                 (R) Cecal Bascule

    3. Contrast Studies
      • rarely necessary
      • barium enema will show an abrupt ‘birds-beak’ blockage at the point of torsion

  4. Treatment
    • endoscopic decompression and reduction is not effective and only delays surgery
    • prompt surgery, reduction of the volvulus, and assessment of bowel viability are the mainstays of therapy

    1. Gangrenous Bowel
      • resection is mandatory
      • resection, ileostomy, and mucous fistula is the traditional management
      • resection with primary anastomosis to nondilated colon appears to be equally safe in a stable patient
      • the nonviable bowel should not be detorsed to avoid reperfusion injury

    2. Viable Bowel
      • several different treatment options are available
      • tube cecostomy fixes the cecum in place but is associated with many complications (wound infection, cecal necrosis, intraperitoneal leak, and persistent fecal fistula)
      • cecopexy involves suturing the tenia of the cecum and ascending colon to the lateral abdominal wall - this avoids an anastomosis, but is technically difficult and has a high recurrence rate
      • right hemicolectomy or ileocecectomy is usually the procedure of choice

Acute Colonic Pseudo-obstruction

  1. Definition
    • acute colonic distention in the absence of mechanical obstruction

  2. Pathogenesis
    • exact etiology remains unknown
    • one theory is that sympathetic overactivity overrides the parasympathetic system responsible for motility
    • most commonly involves the cecum and right colon
    • increasing colon diameter increases colon wall tension, with a resultant increase in the risk of colon ischemia and perforation
    • the risk of colon perforation increases when the cecal diameter is greater than 10 – 12 cm and when the duration of dilation is great than 6 days

  3. Clinical Manifestations
    • abdominal distention (100%), mild abdominal pain (80%), nausea/vomiting (60%)
    • bowel sounds are usually present
    • severe abdominal pain, fever, and an elevated wbc suggest ischemia or perforation
    • occurs almost exclusively in hospitalized patients
    • commonly occurs after nonoperative trauma and orthopedic procedures

  4. Diagnosis
    • abdominal films show diffuse colonic distention indistinguishable from obstruction
    • CT scan is valuable to rule out mechanical obstruction
    • water-soluble contrast enemas can reliably distinguish between mechanical obstruction and pseudo-obstruction, but they can raise intracolonic pressure and cause perforation
    • colonoscopy can be used for diagnosis and therapy, but runs the risk of perforation

    Colonic Pseudoobstruction KUB
  5. Treatment
    1. Initial Maneuvers
      • cecal distention > 12 cm and distention > 6 days is associated with a perforation rate of 3%
      • NPO, correction of electrolyte disorders (potassium, magnesium, calcium), NG decompression, rectal tube attached to gravity drainage
      • discontinue medicines that slow colonic motility: opioids, anticholinergics, calcium channel blockers
      • ambulation if possible
      • laxatives worsen the problem and should be avoided
      • most patients will improve with this plan

    2. Failure to Improve
      • if there is no clinical improvement within 24 to 48 hours, there are additional treatments to try:

      1. Neostigmine
        • enhances parasympathetic activity (anticholinesterase inhibitor)
        • mechanical obstruction must be ruled out
        • success rates between 60% to 100%
        • usually works within 10 minutes
        • most significant side effect is bradycardia
        • must be given in a telemetry unit with atropine immediately available

      2. Epidural Anesthesia
        • sympathetic blockade can relieve pseudo-obstruction

      3. Endoscopic Decompression
        • used when patients have failure of or cannot tolerate neostigmine
        • bowel should not be prepped
        • long decompression tube is usually placed
        • 20% of patients require multiple procedures
        • perforation rate is 3%

      4. Percutaneous Cecostomy Tube
        • reserved for patients who have failed supportive therapy, neostigmine, endoscopic decompression, and who are poor surgical candidates
        • associated with multiple complications: peritonitis, wound infection, tube patency, inadequate decompression

      5. Surgery
        • reserved for patients who fail all less invasive measures or who develop peritonitis or perforation
        • loop colostomy is the preferred procedure if there is no ischemia or perforation
        • Hartmann procedure will be required for perforation or ischemia







References

  1. Schwartz, 10th ed., pgs 1219 - 1221
  2. Sabiston, 20th ed., pgs 1334 - 1339
  3. Cameron, 11th ed., pgs 185 – 187, 187 – 190
  4. UpToDate. Sigmoid Volvulus. Richard A. Hodin, MD. March 04, 2020, pgs 1 – 20.
  5. UpToDate. Cecal Volvulus. Richard A. Hodin, MD. March 02, 2020, pgs 1 – 19.
  6. UpToDate. Acute Colonic Pseudo-obstruction (Ogilvie’s Syndrome). Michael Camilleri, MD. Jan 30, 2020. Pgs 1 - 22.