Sigmoid volvulus

Dr Jeremy Jones et al.

Sigmoid volvulus is a cause of large bowel obstruction and occurs when the sigmoid colon twists on the sigmoid mesocolon.

Large bowel volvulus accounts for ~5% of all large bowel obstructions, with ~60% of intestinal volvulus involving the sigmoid colon 6. It is more common in the elderly 7.

Symptoms are that of a large bowel obstruction: constipation, abdominal bloating, nausea and/or vomiting. Onset may be acute or chronic.

Aetiology

There is a wide range of causes; some are region-specific 5:

  • chronic constipation and/or laxative abuse
  • fibre-rich diet (especially in Africa)
  • Chagas disease (especially in South America)
Associations

Sigmoid volvulus is differentiated from a caecal volvulus by its ahaustral wall and the lower end pointing to the pelvis.

Abdominal radiograph

Abdominal radiographs will show a large, dilated loop of the colon, often with a few air-fluid levels. Specific signs include:

Fluoroscopy

Although now uncommonly performed, a water soluble contrast enema exquisitely demonstrates this condition, with the appearances described as the beak sign (or bird beak sign).

CT

Rectal tube insertion is successful in treating 90% of cases 5. The mortality rate is 20-25% 7. The most serious complication is bowel ischaemia.

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Article Information

rID: 6398
Synonyms or Alternate Spellings:
  • Sigmoid colon volvulus

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Cases and Figures

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    Case 6: Frimann Dahl’s sign - sigmoid volvulus
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