Bowel incontinence (fecal incontinence) can range from an infrequent involuntary passage of small amounts of stool to a total loss of bowel control. Some people with fecal incontinence feel the urge to have bowel movements but are unable to wait to reach a bathroom. Other people don’t feel the sensation of a pending bowel movement, passing stool unknowingly. Normal bowel control relies on the proper function of the:
- pelvic muscles
- rectum, part of the lower end of the large intestine
- anal sphincter muscles, the muscles in the anus
- nervous system
Injury to any of these areas can result in fecal incontinence. Common causes of fecal incontinence include:
Fecal impaction
Chronic constipation can lead to a fecal impaction. This happens when a hard stool gets stuck in the rectum. The stool can stretch and weaken the sphincter, which makes the muscles incapable of stopping normal passage. Another complication of fecal impaction is leakage of liquid fecal matter through the anus.
Diarrhea
Diarrhea is the result of loose or liquid stools. These loose stools can cause an immediate need for a bowel movement. The need can be so sudden that you don’t have enough time to reach a bathroom.
Hemorrhoids
External hemorrhoids can block the sphincter from closing completely. This allows loose stool and mucus to pass involuntarily.
Muscle damage
Damage to the anal sphincter will prevent the muscles from keeping the anus tightly closed. Muscle damage can occur during a difficult vaginal childbirth, when doctors have to use forceps or make a small cut (an episiotomy) to make a larger opening. Surgery in or near the anorectal region, trauma, and constipation can damage the sphincter muscles.
Nerve damage
If the nerves that control sphincter movement are damaged, the sphincter muscles won’t close properly. When this happens, you may also not feel the urge to go to the bathroom. Some causes of nerve damage include:
- trauma from giving birth
- chronic constipation
- stroke
- diabetes mellitus
- multiple sclerosis (MS)
Pelvic floor dysfunction
Women can undergo damage to the muscles and nerves in their pelvis while giving birth, but symptoms of pelvic floor dysfunction may not be immediately noticeable. They may occur years later. Complications include:
- weakness of the pelvic muscles that are used during bowel movements
- rectal prolapse, which is when the rectum protrudes through the anus
- rectocele, which is when the rectum bulges down into the vagina
Some men may also develop pelvic floor dysfunction.
Older age.
Muscles in the rectum and anus naturally weaken with age. Other nearby structures in the pelvis area also loosen with age. This adds to the general weakness seen in that area of the body, leading to problems with stool management. Loose stool is more difficult to manage than solid stool. When a large amount of loose stool arrives rapidly in the rectum, there may not be enough warning to reach the bathroom in time.
Inability of the rectum to stretch
If the muscles of the rectum are not as elastic as they should be, excess stool that builds up can leak out. Inflammatory bowel disease (such as Crohn’s disease) can also affect the rectum’s ability to stretch. The scars resulting from surgery and radiation therapy can also stiffen the muscles of the rectum.
Other medical conditions
Certain medical conditions, such as rectal prolapse (the rectum falls down into the anus) or rectocele (the rectum pushes into the vagina), or chronic constipation where stool leaks around a large stool ball, can lead to fecal incontinence.
Other causes
Laxative abuse, radiation treatments, certain nervous system and congenital (inherited) defects, inflammation (swelling), and inflammatory bowel disease may affect the ability to regulate stool.
If you are experiencing bowel incontinence, it is important to speak with a healthcare provider to determine the cause and receive appropriate treatment.