76-year-old male.
* Presents with acute abdominal pain, enlarged abdomen and no defaecation since a few days.
What do you see?
Abdominal CT scan shows dilated colon loops with a calibre change in the sigmoid. Whirl of mesenterial vessels.
Differential diagnosis is Sigmoid volvulus. This was confirmed on OR.
Sigmoid volvulus is differentiated from a cecal volvulus by its ahaustral wall and the lower end pointing to the pelvis.
Abdominal radiographs will show a large, dilated loop of the colon, often with a few gas-fluid levels. Specific signs include coffee bean sign and absent rectal gas.
CT scan will show large gas-filled loop lacking haustra, forming a closed-loop obstruction. Specific signs include:
– whirl sign: twisting of the mesentery and mesenteric vessels
– bird’s beak sign: if rectal contrast has been administered
– 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
Rectal tube insertion for treatment is successful in treating 90% of cases. 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 of sigmoid volvulus is 20-25%. The most serious complication is bowel ischemia, not blow-out perforation as you might expect.
