Rectal stricture

Rectal stricture has been defined as the inability to pass a rigid proctoscope (12 mm diameter) or a rigid sigmoidoscope (19 mm diameter) through the affected cross-section of rectum. Anal stricture versus rectal stricture Anal strictures are usually located at the anal verge in a narrow band, but sometimes they involve the entire length of the anal canal. Surgically and clinically, the anal canal is usually defined as the zone from the anal verge to the anorectal ring (at the level of the external anal sphincter and the puborectalis muscle). The anorectal ring is easy to identify when patients are asked to squeeze during digital rectal examination. Anatomically, the anal canal is defined as the zone from the anal verge to the dentate line (pectinate line). This is a line formed by the lower ends of the anal columns and represents the embryological junction between the hindgut and the proctodeum. Both rectal stricture and anal stricture (anal stenosis) are types of colonic stricture. They both can also be more widely categorized as gastrointestinal strictures. However, rectal strictures behave differently to colonic strictures because of the proximity of the rectum to the anal canal and pelvic organs, and because of different blood supply. ==Signs and symptoms==

There may be no symptoms (clinically silent stricture), or only minor symptoms, but may get worse over time. When symptoms are caused, the term "clinically relevant rectal stricture" is used. • Fecal incontinence (due to overflow diarrhea). • Tenesmus. • Fecal impaction. ==Diagnosis==

The first step is exclusion of malignant causes. This may involve tissue biopsy, endorectal ultrasound, computed tomography, and magnetic resonance imaging. The next step is assessment of the stricture. The distance from the anal verge, the diameter of the narrowest point of the stricture, and the longitudinal length are ascertained. The degree of narrowing can be assessed with a water-soluble contrast enema. ==Classification==

Rectal strictures are usually classified as benign or malignant (associated with cancer). Benign Benign rectal strictures can be further subcategorized as primary (caused by diseases) and secondary (caused by complication of surgery). Secondary strictures very often occur at the site of a previous surgical anastomosis. Primary strictures have various causes, including different inflammatory disease processes. Causes of benign strictures include: • Stricture at the site of surgical anastomosis (The most common type of benign rectal stricture.) • Inflammatory bowel disease (e.g., Crohn's disease or ulcerative colitis). • After submucosal endoscopic dissection. • Radiotherapy. • Ischemia. • Penetrating injury. • Foreign body trauma, e.g. chronic use of suppositories. • Caustic injury. • Endometriosis. • Pelvic abscess. • perianal fistula. • Sexually transmitted infections (e.g., lymphogranuloma venereum). • Tuberculosis. • Actinomycosis. • Solitary rectal ulcer syndrome. Malignant Acute bowel obstruction is a common presenting manifestation of colorectal cancer which is locally advanced. Malignant strictures may also develop in the context of inflammatory bowel disease. Treatment for malignant strictures is ideally resection (surgical removal) with or without radiotherapy. If resection is not possible or not sensible, symptoms of the stricture may be palliated with radiotherapy, stents, or debulking. Possible malignant processes which may cause rectal stricture include: • Primary rectal cancer. • Recurrent rectal cancer. • Ovarian cancer. • Prostate cancer. • Lymphoma. • Sarcoma. ==Causes==

The narrowing may be because of an intrinsic process occurring within the lumen of the rectum (luminal), within the wall of the rectum (mural), or it can be due to an extrinsic process that is compressing the rectum from the outside (extramural). In the case of external compression of the bowel, the term pseudostricture may be used. According to one review of a total of 730 cases, those which formed after anastomosis represented 74% of all reported benign rectal strictures. Inflammatory bowel disease Inflammatory bowel diseases (IBD) include ulcerative colitis, which affects only the colon, and Crohn's disease, which may affect any section of the gastrointestinal tract. The relapsing-remitting, chronic inflammation in the bowel wall can lead to the development of colonic strictures, including rectal strictures. If they cause inflammation, chronic use of suppositories may cause rectal stricture, Thermal burns are possible if hot water enemas are attempted by patients or practitioners of alternative medicine in the belief that they will provide a stronger stimulus for evacuation of stool. Such rectal strictures are usually located in the proximal rectum, and are one of the most common features of late radiation damage. In one report, herpes simplex virus 2 was implicated as the cause of a rectal stricture. and hemorrhoidectomy. ==Treatment==

How a rectal stricture is treated depends on the exact cause, the distance from the anal verge, the degree of narrowing, the severity of symptoms, and the health of the patient. Dilation For rectal strictures which are mild and close to the anal verge (<6 cm), digital dilation (with fingers) or dilation with instruments is possible. However, this view is now challenged. Stents may be used as the definitive treatment of a stricture, or as a temporary measure to stabilize a patient with acute obstruction before another procedure is carried out. ==References==