Volvulus happens when a section of the intestine twists around itself and the tissue that holds it in place, cutting off blood flow and trapping food or stool. The causes depend on which part of the gut is affected and the person’s age, but chronic constipation, abnormal intestinal anatomy, and reduced mobility are the most common factors across all types.
How the Sigmoid Colon Twists
Sigmoid volvulus, which involves the S-shaped loop of the lower colon, is the most common form in adults. It accounts for the majority of volvulus cases worldwide and is driven by two primary mechanisms: chronic constipation and a high-fiber diet. Both cause the sigmoid colon to stretch and elongate over time. A longer, heavier loop of colon sitting on a narrow base of supporting tissue is mechanically prone to twisting, much like a jump rope that flips over itself when slack builds up.
Chronic laxative or enema use adds to the problem by further distending the colon wall, weakening its muscle tone, and creating the conditions for rotation. This is why sigmoid volvulus disproportionately affects older adults, particularly men, nursing home residents who are bedridden, and people with long histories of constipation. Black individuals also have a higher incidence, though the reasons likely involve a combination of dietary patterns and anatomical variation.
Neurological and Psychiatric Conditions
People with neuropsychiatric disorders like Parkinson’s disease and multiple sclerosis face a notably higher risk of sigmoid volvulus. These conditions slow gut motility, the rhythmic muscle contractions that push stool through the colon. The result is severe, persistent constipation that stretches the sigmoid over months and years. Neuroleptic medications, commonly prescribed for psychiatric conditions, compound the problem because they also reduce gut movement as a side effect.
Muscular dystrophies, including Duchenne muscular dystrophy, weaken the muscles of the intestinal wall directly, making the colon more prone to dilation and twisting. Hospitalized and institutionalized patients are at particular risk because they combine multiple factors: reduced physical activity, medication side effects, and often poor hydration.
The “Volvulus Belt” and Diet
In parts of the Middle East, India, South America, Africa, and Russia, volvulus causes roughly 50% of all colonic obstructions. These regions are collectively called the “volvulus belt.” The connection appears to be dietary. Populations in these areas consume diets very high in fiber and plant residue, which increases stool bulk and chronically distends the colon. Over a lifetime, this elongates the sigmoid and its supporting tissue, raising the likelihood of torsion.
By contrast, in Western countries where lower-fiber diets are more common, volvulus accounts for a much smaller share of bowel obstructions. The paradox is worth noting: fiber is broadly beneficial for gut health, but in very high amounts over decades, it can contribute to the anatomical changes that make volvulus possible.
Midgut Volvulus in Infants and Children
Midgut volvulus is a different condition with a different cause, and it primarily affects newborns and young children. It stems from intestinal malrotation, a developmental error that occurs between the fourth and eighth weeks of pregnancy. During normal fetal development, the intestines elongate, push temporarily outside the abdomen, then retract back in while rotating 270 degrees counterclockwise around the main artery supplying the gut. When this rotation is incomplete or doesn’t happen at all, the intestines settle into abnormal positions.
The consequences are twofold. First, the base of the tissue anchoring the small intestine (called the mesentery) ends up abnormally narrow, forming a stalk around which the entire midgut can spin. Second, fibrous bands of tissue develop between the misplaced cecum and the abdominal wall. These bands, known as Ladd’s bands, cross over the second portion of the small intestine and can physically compress it, creating an obstruction point even before twisting occurs. Genetic mutations affecting a signaling pathway involved in intestinal rotation have been identified as one underlying cause of malrotation.
Midgut volvulus is a surgical emergency. Because the twist can cut off blood supply to the entire small bowel, tissue death can happen within hours.
Cecal Volvulus and the Mobile Cecum
The cecum, the pouch at the beginning of the large intestine, is normally fixed to the back wall of the abdomen. In about 11% of the general population, this attachment never fully forms during fetal development. The cecum and the first part of the ascending colon are left free-floating, a condition called mobile cecum. When the cecum is unanchored, it can fold upward or rotate on itself, producing cecal volvulus.
Cecal volvulus tends to occur in younger adults compared to sigmoid volvulus and is less strongly associated with constipation. Prior abdominal surgery can also contribute by creating adhesions, bands of scar tissue that tether parts of the bowel in abnormal positions and serve as pivot points for twisting. Connective tissue disorders, such as Ehlers-Danlos syndrome, may further increase the risk by affecting the structural integrity of the tissues that normally hold the cecum in place.
Pregnancy as a Risk Factor
Pregnancy raises the risk of sigmoid volvulus through a combination of mechanical and hormonal changes. The expanding uterus physically displaces the sigmoid colon, pushing it into unfamiliar positions. At the same time, pregnancy hormones slow gastrointestinal motility, leading to constipation that distends the colon further. Over 70% of pregnancy-related volvulus cases occur in the third trimester, when the uterus is largest and displacement is most extreme. While volvulus during pregnancy is rare overall, it carries serious risks for both the mother and baby because diagnosis is often delayed.
Chagas Disease and Megacolon
In parts of Central and South America, infection with the parasite that causes Chagas disease is an important driver of volvulus. The parasite destroys nerve cells in the intestinal wall over years or decades, progressively paralyzing sections of the colon. The affected segment loses its ability to contract and push stool forward, leading to massive dilation known as megacolon. A colon that has ballooned to several times its normal diameter is highly susceptible to twisting, and patients with Chagas-related megacolon face an elevated risk of volvulus and the bowel ischemia that follows.
Why Timing Matters
The danger of volvulus isn’t just the obstruction itself. It’s the loss of blood supply. When the intestine twists tightly enough to compress its blood vessels, the tissue begins to die. If the bowel is still viable when treatment happens, outcomes are generally good. But once the tissue becomes gangrenous or perforates, mortality climbs steeply. In one study of sigmoid volvulus patients, mortality reached 57% among those who had developed peritonitis (infection spreading through the abdominal cavity) by the time of surgery. Early diagnosis using CT imaging brought mortality down to 16% in patients who were caught before that stage.
This gap underscores why understanding the causes and risk factors matters practically. People with chronic constipation, neurological conditions, a history of abdominal surgery, or known intestinal malrotation are the ones most likely to develop volvulus. Recognizing sudden severe abdominal pain, bloating, and inability to pass gas or stool as potential warning signs can make the difference between a straightforward treatment and a life-threatening emergency.