Symptoms are that of a large bowel obstruction: constipation, abdominal bloating, nausea and/or vomiting. Onset may be acute or chronic.
There is a wide range of causes; some are geographically-specific 5:
- chronic constipation and/or laxative abuse
- fiber-rich diet (especially in Africa)
- Chagas disease (especially in South America)
- chronic neurological conditions (e.g. Parkinson disease, multiple sclerosis, pseudobulbar palsy)
- medications from chronic psychiatric conditions (e.g. chronic schizophrenia)
Abdominal radiographs will show a large, dilated loop of the colon, often with a few gas-fluid levels. Specific signs include:
- coffee bean sign 5
- Frimann-Dahl sign - three dense lines converge towards the site of obstruction
- absent rectal gas 5
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).
- large gas-filled loop lacking haustra, forming a closed-loop obstruction 6,7
- whirl sign: twisting of the mesentery and mesenteric vessels
- bird's beak sign: if rectal contrast has been administered 6
- X-marks-the-spot sign: crossing loops of bowel at the site of the transition
- split wall sign: mesenteric fat seen indenting or invaginating the wall of the bowel
Treatment and prognosis
Rectal tube insertion is successful in treating 90% of cases 5. Occasionally patients suffer from recurrent sigmoid volvulus, for which a surgeon may consider sigmoid colopexy (surgical fixation of the sigmoid colon), or in the surgically unfit, a percutaneous endoscopic colostomy (PEC) might be performed.
The mortality rate is 20-25% 7. The most serious complication is bowel ischemia.
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- 2. Catalano O. Computed tomographic appearance of sigmoid volvulus. Abdom Imaging. 21 (4): 314-7. Abdom Imaging (link) - Pubmed citation
- 3. Levsky JM, Den EI, Dubrow RA et-al. CT findings of sigmoid volvulus. AJR Am J Roentgenol. 2010;194 (1): 136-43. doi:10.2214/AJR.09.2580 - Pubmed citation
- 4. Burrell HC, Baker DM, Wardrop P et-al. Significant plain film findings in sigmoid volvulus. Clin Radiol. 1994;49 (5): 317-9. - Pubmed citation
- 5. Salati U, Mcneill G, Torreggiani WC. The coffee bean sign in sigmoid volvulus. Radiology. 2011;258 (2): 651-2. doi:10.1148/radiol.101882 - Pubmed citation
- 6. Vandendries C, Jullès MC, Boulay-Coletta I et-al. Diagnosis of colonic volvulus: findings on multidetector CT with three-dimensional reconstructions. Br J Radiol. 2010;83 (995): 983-90. doi:10.1259/bjr/35714052 - Free text at pubmed - Pubmed citation
- 7. Brant WE, Helms CA. Fundamentals of Diagnostic Radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781761352. Read it at Google Books - Find it at Amazon