Sigmoid Volvulus
Submitted by Raymond Ropiak

 

• Twisting of loop of intestine around its mesenteric attachment site may occur at various sites in the GI tract
  • Most commonly: sigmoid & cecum
  • Rarely: stomach, small intestine, transverse colon
  • Results in partial or complete obstruction
  • May also compromise bowel circulation resulting in ischemia
• Sigmoid volvulus most common form of GI tract volvulus
  • Accounts for up to 8% of all intestinal obstructions
• Most common in elderly persons (often neurologically impaired)
• Patients almost always have a history of chronic constipation

·     Pathophysiology

• Redundant sigmoid colon that has a narrow mesenteric attachment to posterior abdominal wall allows close approximation of 2 limbs of sigmoid colon à twisting of sigmoid colon around mesenteric axis
• Other predisposing factors
  • Chronic constipation
  • High-roughage diet (may cause a long, redundant sigmoid colon)
  • Roundworm infestation
  • Megacolon (often due to Chagas dz)
• 20-25% mortality rate
• Peak age > 50 yrs.
  • Second largest group à children
• Torsion usually counterclockwise ranging from 180 – 540 degrees
• Luminal obstruction generally @ 180 degrees
• Venous occlusion generally @ 360 degrees à gangrene & perforation
• Signs and symptoms
  • May present as abdominal emergency
    • Acute distension
    • Colicky pain (often LLQ)
    • Failure to pass flatus or stool (constipation is prevailing feature)
    • Vomiting is late sign
  • Distention may compromise respiratory & cardiac function
  • May also present with surprisingly few signs and symptoms in bedridden and debilitated
• Physical examination
  • Tympanitic abdomen
  • Abdominal distention
  • +/- palpable mass

·     Diagnosis

• Abdominal plain films usually diagnostic
  • Inverted U-shaped appearance of distended sigmoid loop
    • Largest  and most dilated loops of bowel are seen with volvulus
  • Loss of haustra
  • Coffee-bean sign à midline crease corresponding to mesenteric root in a greatly distended sigmoid
    • Sigmoid volvulus – bowel loop points to RUQ
    • Cecal volvulus – bowel loop points to LUQ
      • Dilated cecum comes to rest in left upper quadrant
  • Bird’s-beak or bird-of-prey sign à seen on barium enema as it encounters the volvulated loop
• CT scan useful in assessing mural wall ischemia

Photo on left shows large, dilated loop of large bowel with an inverted U-shape
with walls between two volvulated loops pointing from LLQ toward RUQ;
Photo on right shows same patient with decompressed sigmoid volvulus following insertion of rectal tube

·    Differential Diagnosis

• Large bowel obstruction due to other causes à sigmoid colon CA
• Giant sigmoid diverticulum
• Pseudoobstruction

·    Complications

• Colonic ischemia
• Perforation
• Sepsis

Treatment

o    Derotation & decompression by barium enema or with rectal tube, colonoscope, or sigmoidoscope if no signs of bowel ischemia or perforation

• Laparoscopic derotation or laparotomy +/- bowel resection
• Cecopexy à suture fixation of bowel to parietal peritoneum may prevent recurrence
• Recurrence rate after decompression alone à 50%