investigation
Last reviewed 01/2018
The investigation of suspected sigmoid volvulus should comprise abdominal X-rays, both erect and supine. These show an enormously dilated oval gas shadow in the upper abdomen which may be looped on itself to give the typical 'bent inner-tube' - inverted U - sign. The erect film reveals large fluid levels within this loop. The key difference between sigmoid volvulus obstruction and that due to neoplasia at the same site is that in the former, the proximal colon is not distended.
Barium enema is not indicated as it may delay the onset of surgery.