The term “twisted colon” is the common description for the serious medical condition known as colonic volvulus. This life-threatening event occurs when a section of the large intestine rotates around the tissue that supports it, called the mesentery. The twisting action immediately creates an intestinal obstruction, blocking the passage of stool and gas through the digestive tract. This rotation can also severely compromise the blood vessels within the mesentery, quickly leading to a lack of oxygen for the bowel tissue.
Defining Volvulus and Its Primary Locations
Volvulus occurs when a loop of the large bowel twists around its supporting mesentery, creating a closed-loop obstruction. This twisting constricts the blood vessels supplying the intestine, causing ischemia. If not corrected urgently, this lack of blood flow can rapidly progress to tissue death (necrosis) and eventual perforation.
The large intestine has two primary locations susceptible to this twisting: the sigmoid colon and the cecum. Sigmoid volvulus is the most common form, typically occurring in the S-shaped lower portion of the colon located in the left abdomen. This segment is prone to twisting because it naturally has a long, mobile mesentery, and the condition is most often seen in older adults.
Cecal volvulus, which is less frequent, involves the cecum, the pouch that forms the beginning of the large intestine in the right lower abdomen. This type often affects younger individuals, particularly those between 30 and 60 years old. The susceptibility of the cecum stems from a congenital failure of proper fixation, resulting in an abnormally mobile section of bowel that can rotate.
Recognizing the Signs
The onset of a twisted colon is marked by severe and sudden symptoms related to a complete bowel obstruction. The most common sign is intense, cramping abdominal pain that may begin intermittently before becoming constant. This pain is often accompanied by abdominal distension, as gas and fluid accumulate behind the obstruction.
Patients experience absolute constipation, unable to pass any stool or gas. The inability to clear the bowel contents often triggers secondary symptoms, including nausea and forceful vomiting. If the obstruction has been present for a longer period, the vomit may contain bile, appearing green or yellow-green.
Understanding the Underlying Causes
The twisting event is facilitated by anatomical factors that increase the colon’s mobility. A primary factor is a redundant colon, meaning the intestine has extra length or an unusually long mesentery, allowing the loop to rotate. For cecal volvulus, the cause is often a developmental issue where the cecum is not properly fixed to the abdominal wall, making it hypermobile.
Chronic constipation is a major acquired risk factor, particularly for sigmoid volvulus, as it causes the sigmoid colon to become chronically dilated and heavy with retained stool. This prolonged distension stretches the intestinal wall and its mesentery, which increases the likelihood of a twist. High-fiber diets can also contribute to a dilated, loaded colon.
Age is another factor, with sigmoid volvulus being more common in older adults, especially those who have limited mobility or underlying neurological conditions that affect bowel function. Prior abdominal surgery can also leave behind scar tissue or adhesions, which may act as fixed points around which a mobile section of the colon can twist.
Clinical Diagnosis and Necessary Treatment
Diagnosing colonic volvulus begins with a physical examination, where the doctor finds a distended, tender abdomen. Imaging studies confirm the mechanical obstruction and identify its specific location. A standard abdominal X-ray can reveal a characteristic “coffee bean sign” or a massively dilated, U-shaped loop of bowel for sigmoid volvulus.
A Computed Tomography (CT) scan is typically the definitive diagnostic tool. The CT scan shows the exact site of the twist and may display the “whirl sign,” where the mesentery and its vessels spiral around the central point of the torsion. This imaging also assesses for signs of bowel ischemia, indicating a severely compromised blood supply.
Treatment is time-sensitive and depends on the location and the condition of the affected bowel. For many cases of sigmoid volvulus without signs of necrosis, an initial non-surgical procedure called endoscopic decompression may be attempted. A flexible scope is passed into the rectum to gently untwist the colon and relieve the obstruction, often followed by the placement of a rectal tube to prevent immediate recurrence.
If the bowel shows evidence of severe damage or compromised blood supply, immediate surgery is required to untwist the section and remove any dead tissue (colectomy). Cecal volvulus almost always requires surgical intervention, such as a right hemicolectomy, since endoscopic methods are rarely successful. Due to the high risk of recurrence, surgical resection and fixation of the colon are frequently recommended even after successful initial decompression.