What is Sigmoid Volvulus?
A volvulus is the medical term for when the intestine twists around its own blood supply. Specifically, a sigmoid volvulus is when this twist happens at the base of the sigmoid mesentery, which is a part of the lower intestine. This is the most common type of twist that can occur in the colon; others – though less common – can occur in the upper intestine or the transverse colon. This condition is most often seen in patients who are not very mobile, are confined to bed, live in care facilities, and typically experience chronic constipation.
What Causes Sigmoid Volvulus?
A volvulus is a condition that happens when the bowel twists around a small, thin tissue in the abdomen called the mesentery. This usually happens in patients who are less mobile and have a long history of chronic constipation. As a result of constipation, the sigmoid colon, a part of the large intestine, often becomes overly stretched and excessive, which makes it more prone to twisting.
Risk Factors and Frequency for Sigmoid Volvulus
Sigmoid volvulus is seen more frequently in Africa due to dietary and physical reasons. People in Africa often have a diet high in fiber, which could contribute to this condition. Additionally, people of African descent tend to have a narrower base of the sigmoid mesentery, a tissue in the abdomen, compared to other races. This particular physical characteristic leaves them more prone to developing a sigmoid volvulus.

Signs and Symptoms of Sigmoid Volvulus
Patients who have volvulus often tend to be older and may have other health issues. They may have limited mobility or be bedridden, and are frequently from hospices or nursing homes. They often have a history of chronic constipation. The signs and symptoms that usually result in a hospital admission include loss of appetite, lower food consumption, increasingly bloating, and cessation of bowel movement. They may feel discomfort from the significant bloating, but often do not report pain, unless the volvulus has led to a decrease in blood supply and/or a rupture. However, this condition can affect their breathing due to the effect of the distended colon on the diaphragm.
Some patients may suffer from recurrent episodes of volvulus if they have been treated with non-surgical interventions in the past. A recurring volvulus episode should be taken as seriously as a first occurrence and requires the same detailed health history and physical examination.
Upon physical examination, the abdomen is significantly distended and produces a drum-like sound when tapped. Guarding or rebound tenderness can be noticed over areas of reduced blood supply or imminent rupture. If a rupture has already occurred, the patient will have severe inflammation of the peritoneum (the lining of the abdomen). Digital examination of the rectum reveals it to be empty and often large.
- Higher age
- Other existing health issues
- Limited mobility or bedridden
- History of chronic constipation
- Loss of appetite
- Lower food consumption
- Increasing bloating
- Cessation of bowel movement
- Significant abdominal distension
- Discomfort
- Respiratory compromise
Testing for Sigmoid Volvulus
In the process of determining your diagnosis and treatment plan, your doctor will likely order standard blood tests. These tests, which include a full blood count and kidney function tests, are important for two reasons – they aid in restoring normal body function and assess the condition of your kidneys to determine if it’s safe for you to undergo a CT scan with contrast.
X-rays of your abdomen could show signs of potential issues that are typical of certain conditions – signs that resemble the shapes of a coffee or kidney bean or an expanded part of the large intestine known as the colon. Depending on how long you’ve been experiencing symptoms, the part of the colon that’s closer to the small intestine can release air or fluid into the small intestine – but this only happens if a specific valve between the small and large intestines isn’t working properly.
In addition, CT scans can show a twisting of the membrane connecting the colon to the abdominal wall (mesentery). This, along with an enlarged loop of the sigmoid colon (part of the colon) often filled with air or fluid, are characteristic signs often seen in these cases. If free air is seen either on the x-ray or the CT scan, this is an indication of a more serious issue – a ruptured bowel – which needs immediate attention.
CT scans are particularly helpful in establishing a diagnosis and differentiating the cause of blockage in the large bowel. This is especially true if a patient reports symptoms for the first time and hasn’t had any previous tests on their colon, such as a colonoscopy. The CT scan helps doctors rule out other potential causes, such as a malignant tumor.
Treatment Options for Sigmoid Volvulus
Before any surgery, it’s crucial that the patient is properly hydrated with an IV (a fluid-filled tube in their vein) and that any imbalances in their body’s electrolytes (chemicals that help the body function) are fixed. A nasogastric tube, a tube that goes through the nose into the stomach, can relieve pressure in the upper part of the digestive tract.
If a condition called sigmoid volvulus is present, which means the large intestine has twisted around itself, doctors might try to untwist it with a special tube at the patient’s bedside, using a rigid sigmoidoscope, a small camera that can look inside the sigmoid colon (the end part of the colon). If this doesn’t work or there is worry about the health of the bowel wall, a procedure called a flexible sigmoidoscopy may be used. This involves gently pumping air into the colon while the inside of the colon is checked for signs of damage with the sigmoidoscope.
Patients who can’t be treated this way, or if part of their large intestine isn’t healthy, may need surgery. The typical surgery for this involves removing the twisted part of the large intestine, which is called a sigmoid colectomy. Depending on what the surgeon discovers during the procedure and the patient’s overall health, the colon may be reconnected or an opening (stoma) may be made in the abdominal wall for waste to pass through, known as an end colostomy.
If the large intestine has a hole in it, an immediate surgery called a laparotomy is needed to clean out any waste that may have leaked into the abdomen and to remove the damaged part of the bowel.
Patients who keep having episodes of sigmoid volvulus that can be treated without surgery can discuss with their doctor about having an elective (planned) surgery to remove the part of the large intestine that keeps twisting, which could prevent the need for emergency hospital admissions in the future. This surgery can usually be done with the ends of the colon reconnected, unless the patient has other serious health conditions.
What else can Sigmoid Volvulus be?
When considering a diagnosis, physicians have a list of several conditions that present with symptoms similar to each other. Here are some possibilities:
- Abdominal Aortic Aneurysm
- Acute Gastroenteritis
- Aortoenteric Fistula
- Early Appendicitis
- Bowel Obstruction
- Bowel Perforation
- Diabetic Ketoacidosis
- Gastroparesis
- Mesenteric Ischemia
- Sickle Cell Crisis
- Volvulus
Doctors will typically examine these potential conditions carefully and run appropriate tests to reach the correct diagnosis.