Sigmoid volvulus and cecal volvulus

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. 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. 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.

See “Midgut volvulus and intestinal malrotation” for volvulus in a neonate or infant.

• Incidence
  • Volvulus: 3^rd most common cause (∼ 10–15%) of intestinal obstruction in the United States
• Age ^[1][2]
  • Sigmoid volvulus: ∼ 70 years
  • Cecal volvulus: 40–60 years
• Sex ^[1][2]
  • Sigmoid volvulus: ♂ > ♀
  • Cecal volvulus: ♀ >♂

SigmOid volvulus is more common in Older individuals while Midgut volvulus and Malrotation are more common in Minors.

Epidemiological data refers to the US, unless otherwise specified.

Risk factors

• Long mesentery ^[3]
  • Acquired (sigmoid volvulus): chronic constipation , high-fiber diet resulting in bulky stools → chronic overloading of the sigmoid colon → lengthening of the sigmoid colon and its mesentery → increased risk of torsion
  • Congenital (cecal volvulus): abnormally mobile cecum → predisposition of the cecum to rotate on its axis (axial torsion) or fold upwards (cecal bascule)
• Megacolon (Hirschsprung disease, Chagas disease)
• Intestinal bands/adhesions
• Decreased pelvic space: pregnancy or pelvic mass
• Previous history of volvulus

• Torsion of bowel on its axis ^[4]
  • Closed-loop mechanical bowel obstruction → accumulation of gas and feces within the loop → increased intraluminal pressure → impaired capillary perfusion of bowel → bowel strangulation, ischemia, and gangrene
  • Torsion of the mesenteric vascular pedicle → occlusion/thrombosis of mesenteric vessels → bowel strangulation, ischemia, and gangrene
• Location: may affect all parts of the bowel ^[5]
  • Sigmoid volvulus (most common, 80%)
  • Cecal volvulus (15%)
  • Transverse colon volvulus (3%)
  • Splenic flexure volvulus (2%)

Sigmoid volvulus

• 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

Cecal volvulus

• Types ^[6]
  • Axial torsion of the cecum (90% of cases): the cecum rotates on its mesenteric axis → bowel obstruction with vascular compromise
  • Cecal bascule (10%): the cecum folds upwards onto the ascending colon → bowel obstruction often without vascular compromise
• Clinical features
  • Acute presentation: features of small bowel obstruction
  • Insidious onset: recurrent episodes of right lower abdominal pain

• 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/inverted U sign, kidney bean sign): dilated loop of bowel (sigmoid colon) with absent haustrae that arises in the left lower abdomen and extends towards the right upper abdomen
    • Proximal colonic and small bowel dilation, with air-fluid levels
    • Absence of air in the rectum
  • Cecal volvulus: dilated loop of bowel (cecum) with maintained haustrae that arises in the right lower abdomen and extends towards the left upper abdomen
    • Upward displacement of the appendix
    • Dilated small bowel loops with multiple air-fluid levels
    • The colon distal to the obstruction does not dilate
  • Cecal bascule: dilated cecum in the center of the abdominal cavity; an air-distended appendix may also be seen
  • Bowel perforation: air under diaphragm ^[7]
• CT scan
  • Whirl sign: pathognomonic for volvulus ^[8]
  • Specific features of sigmoid/cecal volvulus are similar to those seen in x-rays
  • Demonstrates bowel ischemia , or perforation , if present
• Barium enema: : bird beak sign (tapering of the dye column at the site of the twist)
  • In cecal bascule, the end of the barium column is rounded, rather than tapered (teardrop sign).
  • Cecal volvulus: normal-sized colon with bird's beak sign at the cecum; dye does not enter the small bowel
  • Sigmoid volvulus: normal-sized rectum with bird's beak sign at the sigmoid; dye does not enter the sigmoid colon

References:^{[7][8][9][10][11][12][13][14][15]}

Differential diagnoses of sigmoid volvulus

• Acute megacolon
• Toxic megacolon
• Other causes of mechanical bowel obstruction (e.g., colon cancer, strictures, cecal volvulus)

Differential diagnoses of cecal volvulus

• Sigmoid volvulus
• Small bowel obstruction (e.g., adhesions, tumors, intussusception)

The differential diagnoses listed here are not exhaustive.

Treatment of sigmoid volvulus ^[16][17]

• Initial resuscitation: IV fluids; acid-base and electrolyte imbalance correction; NPO; placement of a nasogastric tube
• Evaluation
  • No signs of peritonitis : rigid/flexible endoscopic decompression, detorsion, and reduction of the volvulus → inspection of the mucosa for signs of ischemia ^[18]
    • 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 ^[18]
• Surgery
  • Sigmoid colectomy and primary anastomosis : indicated in hemodynamically stable patients with viable bowel ^[17]
  • Hartmann procedure: indicated in hemodynamically unstable patients or those with ischemic/gangrenous bowel

Treatment of cecal volvulus ^[19]

• Initial resuscitation (See “Treatment” of sigmoid volvulus above.)
• Surgery
  • Hemodynamically stable patients: ileocecal resection or right colectomy with ileocolic anastomosis
  • Hemodynamically unstable patients
    • Cecostomy ^[3][20]
    • Detorsion with cecopexy ^[21]