Rectal Stricture
An abnormal narrowing of the rectum or anal canal
Quick Facts
- Type: Digestive (anorectal) condition
- Common causes: Scarring, inflammation, surgery
- Main symptom: Difficulty passing stool
- Treatment: Dilation, surgery, treating the cause
Overview
A rectal stricture is a narrowing of the rectum or anal canal that restricts the normal passage of stool. The rectum is the final section of the large intestine, and when its walls become tightened by scar tissue or chronic inflammation, the channel through which waste leaves the body becomes smaller than normal.
Strictures can range from mild narrowing that causes only minor changes in bowel habits to a tight blockage that makes passing stool painful or nearly impossible. Most rectal strictures develop gradually as the result of healing and scarring after inflammation, surgery, radiation, or injury. With proper diagnosis, many can be widened and managed effectively.
Symptoms
Symptoms depend on how tight the narrowing is and how quickly it has developed. Common features include:
- Difficulty passing stool or a feeling of incomplete emptying
- Thin, narrow, or ribbon-like stools
- Straining during bowel movements
- Constipation that is new or worsening
- Pain or discomfort in the rectum or anus, especially when passing stool
- Bloating or cramping when stool builds up behind the narrowing
If a stricture becomes severe enough to block the bowel completely, it can cause inability to pass stool or gas, abdominal swelling, and vomiting. This is a medical emergency and needs prompt evaluation.
Causes
Rectal strictures form when the wall of the rectum is damaged and heals with scar tissue that pulls the channel narrower. Frequent causes include:
- Inflammatory bowel disease: Long-standing Crohn's disease in particular can scar the bowel and produce strictures.
- Surgery: Operations on the rectum or anus, including for hemorrhoids or cancer, can leave scar tissue at the surgical site.
- Radiation therapy: Radiation to the pelvis for prostate, cervical, or rectal cancer can cause delayed narrowing.
- Chronic inflammation or infection: Repeated abscesses, fistulas, or certain infections can scar the tissue.
- Ischemia: Reduced blood supply to the rectum can lead to scarring.
- Cancer: A tumor of the rectum can narrow the passage and must always be ruled out.
Risk Factors
- A history of Crohn's disease or ulcerative colitis
- Previous anal or rectal surgery
- Pelvic radiation therapy
- Recurrent anal abscesses or fistulas
- Chronic constipation with straining
- Older age, which is also a risk factor for rectal cancer
Diagnosis
A doctor evaluates a suspected rectal stricture with a history, physical examination, and tests to confirm the narrowing and find its cause:
- Digital rectal examination: A gloved finger can often feel a low stricture and assess its tightness.
- Endoscopy: Sigmoidoscopy or colonoscopy lets the doctor see the narrowed area, judge its length, and take biopsies to rule out cancer.
- Imaging: A contrast enema (barium study) or CT scan can map the location and extent of the narrowing.
Biopsy is especially important because it is essential to confirm whether a stricture is benign scar tissue or caused by a tumor.
Treatment
Treatment is chosen according to the cause, location, and severity of the stricture, and aims to relieve symptoms and restore normal bowel passage.
- Dilation: Gentle stretching of the narrowed area, done by hand, with dilators, or with a balloon during endoscopy, is often the first approach for short benign strictures and may be repeated over time.
- Treating the underlying cause: Controlling inflammatory bowel disease with medication can prevent strictures from worsening.
- Surgery: Strictures that are long, recurrent, or cause severe blockage may need a surgical procedure to remove or reconstruct the narrowed segment.
- Stool softeners and fiber: These help stool pass more easily and reduce straining while the stricture is being managed.
When a stricture is caused by cancer, treatment focuses on the underlying tumor.
Prevention
- Follow up closely after anal or rectal surgery to catch narrowing early
- Keep inflammatory bowel disease well controlled with prescribed treatment
- Avoid chronic straining by eating enough fiber and staying hydrated
- Report new changes in bowel habits or stool shape promptly
- Attend recommended screening so rectal cancer is found early
When to See a Doctor
See a doctor if you notice persistently thin or ribbon-like stools, ongoing difficulty passing stool, or new constipation, especially with rectal pain or bleeding. Seek emergency care if you cannot pass stool or gas at all, have severe abdominal pain or swelling, or are vomiting, as these can signal a complete blockage of the bowel.
Frequently Asked Questions
What are the main symptoms of a rectal stricture?
The most typical signs are difficulty passing stool, thin or ribbon-like stools, straining, and a feeling of incomplete emptying. Some people also have rectal pain or worsening constipation as the narrowing tightens.
What causes a rectal stricture?
Most rectal strictures result from scar tissue forming after inflammation, surgery, radiation, or recurrent abscesses. Crohn's disease and pelvic radiation are common causes, and a tumor must always be ruled out.
Can a rectal stricture be cured?
Many benign strictures can be effectively widened with dilation and managed by treating the underlying cause. Tight, long, or recurring strictures may need surgery, and treating any inflammatory bowel disease helps prevent recurrence.
Is a rectal stricture dangerous?
A mild stricture is usually manageable, but a severe one can block the bowel completely. Inability to pass stool or gas, severe abdominal pain or swelling, and vomiting are emergencies that need immediate care.
How is a rectal stricture diagnosed?
Doctors use a digital rectal exam, endoscopy such as sigmoidoscopy or colonoscopy, and sometimes imaging to see the narrowed area. A biopsy is often taken to confirm whether the stricture is scar tissue or caused by cancer.
References
- MedlinePlus, U.S. National Library of Medicine. Anal and rectal disorders.
- Crohn's & Colitis Foundation. Strictures in inflammatory bowel disease.
- American Society of Colon and Rectal Surgeons (ASCRS). Anorectal conditions.
- Mayo Clinic. Crohn's disease and bowel complications.