Most of us acquire control over our bowel movements by the age of four years. To a certain extent, this control allows us to hold back the defecation process till an appropriate place and time as we are aware that soiling ourselves is inappropriate. Bowel accidents refer to episodes of involuntary defecation caused by an inability to hold back a bowel movement even for a short period of time. The condition is also known as bowel incontinence or fecal incontinence.
Bowel accidents are common in young children before they are toilet trained. During adulthood, bowel accidents should not occur since adults have fully developed bowel control. However, bowel accidents do occasionally happen in adults, especially in the elderly due to some underlying medical condition. One of the most common medical condition that can cause bowel accidents is severe gastroenteritis. With certain conditions particularly seen in the elderly, bowel accidents may be much more common.
Control of Bowel Movement
The control of bowel movement is a complex process. The process of defecation begins when stool formed in large intestine (also known as colon) is pushed into rectum. The walls of rectum stretch due to pressure from the incoming stool. This stretching activates stretch receptors in the walls of rectum, and a signal is relayed by nerves to spinal cord. This creates a strong urge to defecate.
Read more on bowel movement urging.
The urge becomes stronger as the walls of rectum are stretched further due to incoming stool. It compels us to look for a toilet in order to complete the act of defecation. In addition, the external anal sphincter is also relaxed by the signals from the nervous system, in order to facilitate the outward movement of stools. The relaxing of the muscles of external anal sphincter is an involuntary act that we cannot control.
However, we manage to retain stool and hold off the act of defecation by preventing the relaxation of internal anal sphincter. The muscles of the internal anal sphincter are under voluntary control but they can hold off defecation only till the pressure builds up to a certain level. Relaxation of both anal sphincters, coupled with strong contractions of the walls of colon and rectum, lead to expulsion of stool from the body.
Causes of Bowel Accidents
If there is a problem with any of the stages in the control of bowel movement then it can lead to bowel accidents, or leakage of stools. Problems with the muscles and nerves can lead to leaky anal sphincters, and are the most common causes of bowel accidents. Apart from muscle and nerve problems, however, there are other reasons that may also cause bowel accidents.
Conditions that cause diarrhea are one of the most common causes of bowel accidents in any age group. Examples of diarrheal conditions that may cause bowel accidents include gastroenteritis and food poisoning. In severe diarrhea, bowel accidents may occur due to the inability of an affected person to find a toilet in time. Such bowel accidents are temporary. Ir stops once the diarrheal disease resolves.
Bowel accidents in diarrheal diseases are very much expected. However, bowel accidents may also occur in some cases of constipation, which is a condition characterized by difficulty in passing stools. In cases of severe constipation, stool becomes very hard due to fecal impaction. The solid stool forms a plug, and prevents the flow of stool.
However, fluid stool coming from behind can pass around this solid mass and leak out of the anus. This can lead to soiling of underwear. Also, passing large hard masses of stool during constipation may cause damage to rectal and anal regions, leading to higher chances of bowel accidents later on.
As described above, bowel movement can be controlled voluntarily up to a point. The muscles of colon, rectum, anal sphincters, and pelvic floor are involved in the control of defecation process. A problem with any of these muscles (such as weakening or damage of muscles) could cause ineffective control of bowel movements, leading to bowel accidents.
There are a variety of conditions that can cause these muscles to become weak or injured. For example, the process of vaginal childbirth can cause injury to the muscles of pelvic floor. Hemorrhoid surgery could also cause injury to the muscles of perineum and pelvic floor. Any other trauma to pelvic and perineal regions can also cause bowel accidents.
Read more on weak bowel movement.
Problems with the nervous system
Muscular contraction and relaxation is mediated through impulses from nervous system. This is the case for both voluntary and involuntary muscular actions. Any problem with the nerves (such as damage or disease) can lead to improper muscular functions, causing bowel accidents. Nerve problems may occur in conditions such as a stroke, head trauma, multiple sclerosis, spinal cord injury, and diabetic neuropathy.
These conditions may, therefore, be associated with bowel accidents. Nerve problems are also commonly associated with vaginal childbirth and long term constipation. Forceps delivery or episiotomy during delivery is a common cause of nerve injury. Nerves can get damaged in chronic constipation due to the constant straining required to pass stools in this condition.
Problems with the rectum
The stretching of the walls of rectum upon entry of stool from the last part of the colon is an important event in the defecation process. This ability of the rectum to stretch and change shape allows control of defecation process. When the walls of rectum become stiff, and are unable to stretch, stool may leak out as soon as it enters the rectum. Stiffness of the walls of rectum happens due to scarring of these walls. Scarring may be caused by injuries seen in conditions such as exposure to radiation (such as during cancer treatment), and inflammatory bowel diseases.
Other causes of bowel accidents
Bowel accidents due to fecal incontinence may also occur in other conditions that adversely affect rectum and anus. Examples include hemorrhoids, rectal prolapse, and rectocele. In hemorrhoids, the veins in rectum become inflamed and swollen. Rectal prolapse occurs when a part of rectum collapses, impairing the closure of anal sphincters. Rectocele is characterized by the formation of an abnormal connection between rectum and vagina.