Bowel Incontinence (Fecal Incontinence)

  • Medical Author:
    Benjamin Wedro, MD, FACEP, FAAEM

    Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

  • Medical Editor: Bhupinder Anand, MD

Bowel incontinence (fecal incontinence) definition

Fecal incontinence can be defined as the unintentional loss of stool (feces) or gas (flatus). It is often due to a failure of one or more of the components that allow the body to control the evacuation of feces, when it is socially appropriate.

A normal bowel movement requires a complex interaction and feedback system between the nerves and muscles of the rectum and anus. The anatomy of this area is complicated. The rectum is a reservoir for holding stool. Two sphincters or circular muscles separate the rectum from the anus and control when the anus should allow a bowel movement. The internal anal sphincter (IAS) is under involuntary control of the body's nervous system, while the external anal sphincter (EAS) can be actively controlled by the indivdiual. In addition, the puborectalis muscle tugs at the junction of the rectum and anus, creating a 90 degree angle, which makes it harder for stool to move involuntarily into the anus.

When the rectum is full and for a normal bowel movement to occur, the IAS relaxes just a little. Cells in the anus can detect feces or flatus and if the brain says that it is an opportune social time to pass gas or have a bowel movement, the puborectalis muscle relaxes, straightening the path from the rectum to the anus. Squatting or sitting helps increase the pressure within the abdomen, and muscles that surround the rectum squeeze its contents, the EAS relaxes and a bowel movement occurs.

If it is not an appropriate time to open the bowel, the puborectalis muscle contracts, the EAS contracts, the rectum relaxes and stool is forced back into the upper part of the rectum, causing the urge to have a bowel movement to be temporarily quieted.

What causes bowel incontinence?

Fecal incontinence occurs because of an underlying disease or illness (it is not considered a "disease"). There are numerous potential causes and many patients have more than one reason to cause loss of bowel control.

Damage to muscles and nerves may occur directly at the time of vaginal childbirth or after anal or rectal surgery.

Neurologic diseases such as stroke, multiple sclerosis, spinal cord injury, and spina bifida can be potential causes of fecal incontinence. Complications of diabetes can also cause peripheral nerve damage leading to incontinence.

Patients with inflammatory bowel disease (Crohn's disease, ulcerative colitis) and irritable bowel disease may develop fecal incontinence.

Stool seepage is different than fecal incontinence. Minor staining can occur in people who have hemorrhoids, rectal fistula, rectal prolapse and poor hygiene. Other causes include chronic diarrhea, parasite infections, and laxative abuse.

Paradoxical diarrhea or overflow incontinence may occur is a a person who has chronic constipation. In paradoxical diarrhea, stool fills the rectum, hardens and becomes impacted. Liquid stool leaks around the fecal mass, imitating incontinence.

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What are the symptoms of bowel incontinence?

Bowel incontinence refers to the inability to control the passage of small amount of stool, liquid or solid, or control flatus.

People are sometimes reluctant to discuss their lack of bowel control because of the social stigma attached to it. Their initial complaint might be anal itching (pruritis ani), a buttock skin infection, or breakdown of the skin and ulcers.

How is bowel incontinence diagnosed?

Taking a history is very important and the health care professional will spend time learning about how often loss of bowel control occurs, in what situations and whether it is solid, liquid, or gas. Past medical and surgical history is important, especially obstetric history or surgery of the anus, including hemorrhoids. It could be several years before the complication of a surgery or childbirth lead to fecal incontinence. Dietary habits and medications (including over-the-counter medications and laxative) will also be considered and evaluated.

Physical examination will likely include a rectal examination to assess sphincter tone. In females, a pelvic exam will also be performed.

While blood tests are not usually needed to make the diagnosis, other tests may be helpful in deciding the potential cause of fecal incontinence. Anal manometry measures the pressure within the rectum, both at rest and when the patient squeezes the anal sphincter. Nerve and muscle conduction studies may be considered. Ultrasound can evaluate the anal sphincters and look for muscle damage.

What is the treatment for bowel incontinence?

The treatment approach for a patient with fecal incontinence is individualized based upon the underlying cause. The purpose is to regulate bowel movements, decrease their frequency, and increase stool firmness and consistency. Often this involves dietary changes and the use of medications that bulk the stool.

Increasing the strength of the muscles of the pelvic floor might be helpful. Kegel exercises and electrical stimulation may be recommended. Biofeedback is often used to help retrain the anal sphincters and have the patient appreciate the sensation of rectal fullness that comes just before the need to defecate.

If the incontinence persists even after maximum medical therapy has been attempted, surgery may be an alternative. If damaged, attempts can be made to repair the muscles of the pelvic floor including the external anal sphincter. The internal anal sphincter function may be enhanced by injecting materials like silicone, carbon beads, or collagen.

As a last resort, where all other options have failed, a colostomy may be performed, where the colon is diverted through the abdominal wall to empty into a removable bag.

What about bowel incontinence in children?

In children, fecal incontinence (also called encopresis) is often due to chronic constipation and overflow incontinence or diarrhea. By definition, there should be at least one inappropriate bowel movement per month for at least three months in a child older than age 4 years. The incontinence usually happens during the day and not at night.

Most often, the diagnosis is made by history and physical examination by the health care professional and further testing is not needed.

Treatment is directed at developing a more routine bowel evacuation schedule and may require changes in diet, behavior modification, and the addition of stool bulking agents.

Can bowel incontinence be prevented?

Maintaining sphincter tone may prevent fecal incontinence. This might include preventing constipation by increasing fiber in the diet and keeping well hydrated and avoiding straining to promote a bowel movement.

Unfortunately, many times the cause of incontinence is childbirth anal surgery. It may be years until the symptoms of incontinence arise.

What is the prognosis for bowel incontinence?

The frequency of fecal incontinence increases with age. Once it occurs, the patient may be able to control the symptoms with diet, medication, and exercise. Many patients may initially benefit from surgery, but that benefit gradually decreases over the years and incontinence may recur.

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Medically Reviewed on 8/17/2016
References
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine

REFERENCE:

Shah, BJ; Chokhavatia, S; Rose, S .Fecal Incontinence in the Elderly. The American Journal of Gastroenterology;2012. 107 (11): 1635 to 46.

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