Case of the Week 7 2015

Answer: Sigmoid volvulus

Scenography demonstrates coffee bean sign. Enhanced axial CT image shows twisting of the mesentery and mesenteric vessels (arrow).

Sigmoid volvulus is a twisting or axial rotation of a portion of bowel about its mesentery. It is a cause of large bowel obstruction.
Large bowel volvulus accounts for ~5% of all large bowel obstructions. Sigmoid volvulus is more common in the elderly.
Symptoms are constipation, abdominal bloating, nausea and/or vomiting. Onset can be acute or chronic.
Sigmoid volvulus is differentiated from a caecal volvulus by its ahaustral wall and the lower end pointing to pelvis.
Plain film reveals a large, dilated loop of colon, often with a few air-fluid levels.
Plain film specific signs:
•coffee bean sign
•Frimann Dahl’s sign – three dense lines converge towards site of obstruction
•absent rectal gas
Fluoroscopy with barium shows the bird of prey sign.
CT
•dilated gas-filled bowel
•whirl sign
•beak sign – if rectal contrast has been administered

References:
1. Janzen DL, Heap SW. Organo-axial volvulus of the sigmoid colon. Australas Radiol. 1992;36 (4): 332-3.
2. Catalano O. Computed tomographic appearance of sigmoid volvulus. Abdom Imaging. 21 (4): 314-7.
3. Levsky JM, Den EI, Dubrow RA et-al. CT findings of sigmoid volvulus. AJR Am J Roentgenol. 2010;194 (1): 136-43.
4. Burrell HC, Baker DM, Wardrop P et-al. Significant plain film findings in sigmoid volvulus. Clin Radiol. 1994;49 (5): 317-9.
5. Salati U, Mcneill G, Torreggiani WC. The coffee bean sign in sigmoid volvulus. Radiology. 2011;258 (2): 651-2.
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.
7. Brant WE, Helms CA. Fundamentals of Diagnostic Radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781761352.