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The causes of fecal incontinence include:

  • Muscle damage. Injury to the rings of muscle at the end of the rectum (anal sphincter) may make it difficult to hold stool back properly. This kind of damage can occur during childbirth, especially if you have an episiotomy or forceps are used during delivery.
  • Nerve damage. Injury to the nerves that sense stool in the rectum or those that control the anal sphincter can lead to fecal incontinence. The nerve damage can be caused by childbirth, constant straining during bowel movements, spinal cord injury or stroke. Some diseases, such as diabetes and multiple sclerosis, also can affect these nerves and cause damage that leads to fecal incontinence.
  • Constipation. Chronic constipation may lead to a mass of dry, hard stool in the rectum (impacted stool) that is too large to pass. The muscles of the rectum and intestines stretch and eventually weaken, allowing watery stool from farther up the digestive tract to move around the impacted stool and leak out. Chronic constipation may also cause nerve damage that leads to fecal incontinence.
  • Diarrhea. Solid stool is easier to retain in the rectum than is loose stool, so the loose stools of diarrhea can cause or worsen fecal incontinence.
  • Loss of storage capacity in the rectum. Normally, the rectum stretches to accommodate stool. If your rectum is scarred or your rectal walls have stiffened from surgery, radiation treatment or inflammatory bowel disease, the rectum can't stretch as much as it needs to, and excess stool can leak out.
  • Surgery. Surgery to treat enlarged veins in the rectum or anus (hemorrhoids), as well as more complex operations involving the rectum and anus, can cause muscle and nerve damage that leads to fecal incontinence.
  • Other conditions. Fecal incontinence can result if the rectum drops down into the anus (rectal prolapse) or, in women, if the rectum protrudes through the vagina (rectocele).
Nov. 06, 2012