Sigmoid volvulus: Causes and treatment of twisted sigmoid colon

sigmoid volvulusSigmoid volvulus is a gastrointestinal condition that frequently leads to large bowel obstruction. It is characterized by a twisted sigmoid colon—the part of the large intestine that is closest to the rectum and anus. Nearly 20 percent of all bowel obstructions occur in the large bowel, and sigmoid volvulus accounts for approximately five percent of these cases.

Sigmoid volvulus is primarily a condition that affects the elderly population, with men being affected by it more than women. If left untreated, serious complications could occur, such as venous infarction—due to decreased blood supply and perforation. This leads to fecal peritonitis, a condition where fecal matter enters the abdominal cavity causing an infection.

What are the causes and risk factors of sigmoid volvulus?


While not as common as other forms of bowel obstruction, sigmoid volvulus is one of the major causes of colonic obstruction in many parts of the world. Sigmoid volvulus is more often encountered in populations from South America, Africa, Asia, and eastern Europe. It rarely occurs in developed countries like Canada and the United States.

The most common causes of sigmoid volvulus development include:

  • Chronic constipation
  • Excessive or prolonged use of laxatives
  • A diet that is too rich in fiber (commonly occurring in Africa)
  • Chagas disease (commonly occurring in Africa)

Risk factors that increase the chances of developing sigmoid volvulus include:

  • Age – people over the age of 50 are more prone to develop sigmoid volvulus
  • Chronic constipation – defined as having less than three bowel movements per week
  • Megacolon – defined as having an abnormal dilation of the colon
  • Gender – males are more likely to develop the condition compared to females

Symptoms of twisted sigmoid colon

The most common symptoms associated with sigmoid volvulus include:

  • Constipation
  • Bloating
  • Nausea/vomiting
  • Abdominal pain – generally located in the lower part of the abdomen
  • Failure to pass gas or stool
  • History of recurrent mild attack that is relieved by passing large quantities of gas or stool
  •  Abdominal distension
  • High fever – in cases of colonic perforation
  • Possible development of colonic ischemic if treatment is delayed
  • Peritonitis – in cases of colonic perforation

Diagnosing sigmoid volvulus

The following tests are the best tools available to diagnose cases of sigmoid volvulus:

  • Abdominal x-ray – can give a general outline of the intestinal tract, allowing the doctor to see if there is bowel dilatation
  • Barium enema – a type of x-ray exam that can detect changes and abnormalities in the large intestine with the use of injected contrast material. This test is seldom done today.
  • Computer tomography – an imaging study that gives the physician a detailed look at internal structures. This test can be used to confirm sigmoid volvulus.
  • MRI – another imagining study that gives a more detailed view of the internal structures of the abdomen.
  • Ultrasonography – with the use of sound waves, an image can be produced to get an idea if bowel obstruction is present. This test is not the most accurate.
  • Sigmoidoscopy – a flexible tube that is inserted into the anus, allowing doctors to examine the rectum and lower (sigmoid) colon. This is typically not needed unless complications of sigmoid volvulus are suspected.

Treating sigmoid volvulus

Acute cases (a situation where a condition occurs in a short span of time) of sigmoid volvulus are considered medical emergencies. This means that emergency care should be taken immediately, as complications such as a perforated colon could occur at any time. The main approach for treatment involves the insertion of a rectal tube to decompress the bowel.

Decompression procedures often involve the patient lying on their left side. The decompression and untwisting of the sigmoid colon are performed with the help of sigmoidoscopy and flatus tubes. Using these two devices, a rush of liquid feces and flatus will relieve the obstruction. This procedure provides immediate relief to the patient suffering from sigmoid volvulus symptoms.


The physician will likely keep the flatus tube in position for approximately one day to maintain decompression and reduce the risk of recurrence. After this intervention, the patient will need to be monitored.

In cases of chronic sigmoid volvulus (developing over a long period of time), changes in diet can benefit the patient before they undergo the procedure previously mentioned and after the procedure has been done. These dietary changes may include:

  • Eating smaller meals – help to keep the pressure in the digestive system under control
  • Consume foods rich in fiber – helps to avoid constipation
  • Avoid spicy or fried foods – may slow down the healing process
  • Drink plenty of water – helps to keep the stool soft and avoid constipation

Related: Twisted bowel (volvulus) in adults: How the bowels twist and how to treat it


Related Reading:

Swollen colon: Causes and symptoms

Bowel obstruction (intestinal obstruction): Causes, symptoms, diagnosis, and treatment

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