A colon stricture is a narrowing of the large intestine, also known as the colon. This narrowing can impede the normal passage of digestive waste through the bowel. It can lead to various gastrointestinal issues, ranging from discomfort to severe blockages.
Understanding Colon Strictures
A stricture refers to an abnormal narrowing of a bodily passage. In the colon, this creates a constricted segment within the large intestine, which is the final part of the digestive tract responsible for forming and eliminating stool. This narrowing can develop in any part of the colon, from the cecum to the rectum, making it difficult for stool and gas to pass through.
The underlying mechanism often involves inflammation within the colon wall. This inflammation, if chronic or severe, can lead to the formation of scar tissue, a process known as fibrosis. As scar tissue accumulates and contracts, it stiffens and narrows the colon’s lumen, the hollow space inside the bowel.
Common Causes of Colon Strictures
Colon strictures arise from various conditions that cause damage or inflammation to the colon. Inflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis, are frequent culprits. In these chronic conditions, repeated cycles of inflammation and healing result in the build-up of scar tissue within the intestinal wall, gradually constricting the passage. Crohn’s disease, in particular, commonly leads to strictures, with estimates suggesting that up to 15% of affected individuals may develop one within 10 years of diagnosis.
Diverticular disease, characterized by small pouches (diverticula) forming in the colon wall, can also lead to strictures. If these pouches become inflamed, a condition called diverticulitis, the resulting swelling and scar tissue can narrow the colon. Ischemic colitis occurs when blood flow to a segment of the colon is reduced, causing tissue damage. The healing process following such damage can involve scar formation, which may lead to strictures, particularly in individuals over 60 years old or in areas of the colon prone to reduced blood supply.
Radiation therapy, often used to treat cancers in the pelvic or abdominal region, can damage colon tissue. This damage may result in inflammation and fibrosis, leading to strictures, sometimes appearing several months to two years after treatment. Surgical complications are another cause, particularly following operations that involve connecting two parts of the colon, known as anastomotic strictures. Scar tissue, reduced blood flow, or infection at the surgical site can cause narrowing after the procedure. Furthermore, the growth of tumors, both benign and malignant (colon cancer), directly obstructs the colon and can lead to stricture formation.
Recognizing the Signs
Recognizing the signs of a colon stricture involves observing changes in bowel habits and experiencing abdominal discomfort. One common symptom is a change in the frequency or consistency of bowel movements, often manifesting as constipation or stools that are noticeably narrower than usual.
Abdominal pain or cramping is frequently reported, often localized in the lower abdomen, and can be constant or intermittent. This pain results from the colon’s efforts to push contents past the constricted area. Other symptoms can include bloating, a feeling of fullness or tightness in the abdomen, and nausea or vomiting, especially if the stricture is causing a significant obstruction. Unexplained weight loss and, in some cases, rectal bleeding may also occur.
Diagnosing and Treating Colon Strictures
Diagnosing a colon stricture involves medical history, physical examination, and imaging studies. A colonoscopy is often considered a primary diagnostic tool, allowing a doctor to visually inspect the inside of the colon using a flexible tube with a camera. During this procedure, tissue samples (biopsies) can be taken to determine the underlying cause of the stricture. Imaging techniques like computed tomography (CT) scans or magnetic resonance imaging (MRI) provide detailed cross-sectional images of the abdomen, helping to identify the location, extent, and potential cause of the narrowing. In some cases, a barium enema, where a liquid containing barium is introduced into the colon to highlight it on X-rays, may also be used.
Treatment for colon strictures depends on the cause, severity, and location of the narrowing. For strictures caused by ongoing inflammation, medical management with corticosteroids or immunomodulators may help reduce swelling and improve the passage. When the stricture is benign, endoscopic balloon dilation is often a first-line treatment. This procedure involves inserting a scope with a balloon into the colon and inflating the balloon at the site of the stricture to widen the passage. Multiple dilation sessions may be necessary, and there is a small risk of complications like perforation.
If endoscopic methods are not sufficient or appropriate, surgical interventions may be considered. Strictureplasty is a surgical option that widens the narrowed segment of the colon without removing it, typically by making incisions along the stricture and then sewing them crosswise. This approach is often preferred for shorter strictures to preserve bowel length. For severe, long, or inaccessible strictures, surgical resection involves removing the constricted portion of the colon and reconnecting the healthy ends. In situations of complete obstruction, a temporary or permanent colostomy, which diverts waste through an opening in the abdomen, might be necessary.