• Clinical science

Volvulus and intestinal malrotation

Summary

Volvulus is defined as the twisting of a loop of bowel on its mesentery and is one of the most common causes of intestinal obstruction. The sigmoid colon, and less frequently, the cecum, are the common sites of volvulus in adults. Volvulus in a neonate or infant almost always presents as a midgut volvulus secondary to intestinal malrotation. Patients typically show features of bowel obstruction (abdominal pain, distension, bilious vomiting) or of bowel ischemia and gangrene (tachycardia, hypotension, hematochezia, peritonitis) in severe cases. The whirl sign and a grossly dilated loop of bowel on an abdominal CT scan establish the diagnosis of volvulus in adults. Upper GI series is the investigation of choice in infants with suspected midgut volvulus, which is seen as a cork-screw duodenum. Sigmoid volvulus without peritonitis is initially managed with endoscopic detorsion, followed by a semi-elective surgery (sigmoid colectomy). Sigmoid volvulus with peritonitis, and all cases of cecal volvulus, require emergency surgery. Endoscopic detorsion should not be attempted in a patient with cecal volvulus because of the high risk of perforation. The Ladd procedure (laparotomy and detorsion of the volvulus) is indicated in all patients with intestinal malrotation since it is impossible to predict if volvulus of the midgut will occur in an asymptomatic patient or not.

Epidemiology

References:[1][2][3][4][5][6][7][8][9][10][11]

Epidemiological data refers to the US, unless otherwise specified.

Risk factors for the development of a volvulus

References:[2][3][4][5][12][13][14][15][16]

Pathophysiology

References:[5][17]

Sigmoid volvulus

Clinical features

  • Previous episodes of abdominal pain, which decreased after explosive passage of stool/gas
  • Slowly (most common) or rapidly progressive symptoms of bowel obstruction
  • If bowel ischemia occurs → tachycardia, hypotension, peritonitis (rebound tenderness), hematochezia or blood on DRE may be present
  • If bowel perforation occurs → obliteration of liver dullness on percussion

Differential diagnoses

Treatment

  1. Initial resuscitation: IV fluids; acid-base and electrolyte imbalance correction; nil per oral; placement of a nasogastric tube
  2. Evaluation
    • No signs of peritonitis: rigid/flexible sigmoidoscopic detorsion of the volvulus → inspection of the mucosa for signs of ischemia
      • No signs of mucosal ischemia → placement of a soft rectal tube (for bowel decompression) → semi-elective surgery within 72 hours of detorsion
      • Signs of mucosal ischemia → emergency surgery (see below)
    • Signs of peritonitis/unsuccessful endoscopic detorsion → broad-spectrum IV antibiotics and emergency surgery
  3. Surgery

References:[18][1][3][4][5][17][19][20][21]

Cecal volvulus

Types

Clinical features

  • Acute presentation: features of small bowel obstruction
  • Insidious onset: recurrent episodes of right lower abdominal pain

Differential diagnoses

Treatment

  1. Initial resuscitation (See “Treatment” of sigmoid volvulus above.)
  2. Surgery
    • Hemodynamically stable patients: ileocecal resection or right colectomy with ileocolic anastomosis
    • Hemodynamically unstable patients
      • Cecostomy
      • Detorsion with cecopexy

References:[1][5][12][19][22][23]

Intestinal malrotation and midgut volvulus

Definition

  • Intestinal malrotation: arrest in the normal rotation of the gut in utero, resulting in an abnormal orientation of the bowel and mesentery within the abdominal cavity
Common types of intestinal malrotation
Nonrotation Incomplete rotation
  • The mesenteric attachment has a wider base than in incomplete rotation

Clinical presentation

Differential diagnoses

Treatment

References:[6][7][24][25][26][27][28][29]

Diagnostics

Volvulus

  • Work-up follows the same protocol as that for bowel obstruction.
  • Abdominal x-ray (erect and supine)
    • Sigmoid volvulus: coffee bean sign (bent inner tube sign)
    • Cecal volvulus: kidney bean sign
    • Bowel perforation: air under diaphragm
  • CT scan
    • Whirl sign: pathognomonic for volvulus
    • Specific features of sigmoid/cecal volvulus are similar to those seen in x-rays
    • Demonstrates bowel ischemia , or perforation , if present
  • Barium enema: : bird's beak sign (tapering of the dye column at the site of the twist)

Intestinal malrotation and midgut volvulus

Imaging in intestinal malrotation and midgut volvulus

Intestinal malrotation

Midgut volvulus

Upper GI series (gold standard in hemodynamically stable patients)

  • Displaced duodenojejunal junction
Barium enema (lower GI series)
Abdominal ultrasound
  • Abnormal position of the superior mesenteric vessels and bowel
  • Whirlpool sign (on color doppler)

CECT scan (oral and IV contrast)

  • Findings similar to those seen on ultrasound
  • Findings similar to those seen on ultrasound
  • Can demonstrate bowel ischemia , or perforation , if present

References:[3][6][7][8][11][23][26][28][30][31][32][33][34][35][36][37][38][39][40][41][42]