Causes Of Fecal Incontinence

There are many possible causes of fecal or bowel incontinence, the most common are: severe constipation, diarrhea, muscle damage and nerve damage. Incontinence occurs when the complex mechanism that maintains continence doesn't function properly.

Normal continence depends on proper functioning of the colon and rectum muscles and nerves, anal sphincter muscles, the brain and the nervous system. If one or more of these elements are not functioning as intended, the result could be bowel incontinence.

Fecal or bowel incontinence can arise from a variety of causes. These include:


Diarrhea, or liquid stool, may be associated with a feeling of urgency or stool leakage due to the frequent waterly stools passing through the anal opening. Besause diarrhea is more difficult to control than solid stools, even people who do not have problems with incontinence can have an accident when having diarrhea.

Diarrhea causes temporary fecal incontinence. If diarrhea is severe (chronic or acute), it can cause serious health complications, such as dehydration.

Pelvic floor dysfunction:

The pelvic floor plays a very important role in maintaining continence. The function of pelvic floor muscles and nerves is critical to activities such as urinating and having bowel movements. Any abnormalities of those muscles and nerves can lead to fecal incontinence.

Examples of some abnormal conditions are: decreased perception of rectal sensation, decreased anal canal pressures, decreased squeeze pressure, impaired anal sensation, a dropping down of the rectum (rectal prolapse), protrusion of the rectum through the vagina (rectocele), and/or generalized weakness and sagging of the pelvic floor. Often the cause of pelvic floor dysfunction is childbirth, and incontinence does not show up until the midforties or later.

Muscle damage

Fecal incontinence is most often caused by injury to one or both of the ring-like muscles at the end of the rectum called the anal internal and/or external sphincters. The sphincters keep stool inside. When damaged, the muscles are not strong enough to do their job, and stool can leak out.

In women, the damage often happens when giving birth. Anal operations or injury to the tissue surrounding the anal region can damage the anal muscles and hinder bowel control. Infections around the anal area may destroy muscle tissue leading to problems of fecal incontinence.

Nerve damage

Bowel incontinence can also be caused by damage to the nerves that control the anal sphincters or to the nerves that sense stool in the rectum. If the nerves that control the sphincters are injured, the muscle does not work properly and incontinence can occur.

If the sensory nerves are damaged, they do not sense that stool is in the rectum. You then will not feel the need to use the bathroom until stool has leaked out. Nerve damage can be caused by childbirth, a long-term habit of straining to pass stool, stroke, and diseases that affect the nerves, such as diabetes and multiple sclerosis.

Loss of storage capacity

Normally, the rectum stretches to hold stool until you can get to a bathroom. But rectal surgery, radiation treatment, and inflammatory bowel disease can cause scarring that makes the walls of the rectum stiff and less elastic. If this happens, the rectum cannot stretch as much and cannot hold as much stool.

Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS) can also make rectal walls very irritated and thus unable to contain stool.


Constipation is one of the most common causes of fecal incontinence and can lead to a build up of large amount of stool in the rectum, a condition called fecal impaction. Fecal impaction is a large mass of dry, immobile bulk of hard stool that cannot be passed. A watery stool from higher in the bowel may then eventually move around the impaction and leak out.

Other possible causes of fecal incontinence are also:
  • Extended period without defecation
  • Severe muscular strain in the abdominal area, particularly when giving birth
  • Spinal Cord Injury