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Sigmoid Volvulus
General Considerations
- 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
- 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
Differential Diagnosis
Treatment
- Laparoscopic de-rotation or laparotomy +/- bowel resection
- De-rotation & decompression by barium enema or with rectal tube, colonoscope, or sigmoidoscope if no signs of bowel ischemia or perforation
- Cecopexy à suture fixation of bowel to parietal peritoneum may prevent recurrence
- Recurrence rate after decompression alone à 50%
Sigmoid Volvulus. Dilated loop of sigmoid colon has a "coffee-bean" shape and
the wall between the two volvulated loops of sigmoid (black arrow) "points" towards the right upper quadrant.
There is a considerable amount of stool in the colon from chronic constipation.
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For this same photo without the annotations, click here
Sigmoid Volvulus. 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
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