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Incomplete Evacuation

Incomplete Bowel or Stool Evacuation

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Updated May 16, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Man sitting on toilet
Richard Kolker/The Image Bank/Getty Images

Considering that a "feeling of incomplete evacuation" is a hallmark symptom of IBS, it is remarkable how little attention it gets. IBS research tends to lump the symptom in with the rest of the unpleasantness that is IBS. This approach is not so helpful to those who struggle with this discomfort on a regular basis. This article is offered as a way to try to fill in this information gap, with the hope that it will lead to some self-care strategies that you can try in an effort to reduce any unnecessary discomfort.

What Is Incomplete Evacuation?

Incomplete evacuation is a subjective sensation that a bowel movement has not been as complete as it should be. When a person is constipated, passage of small, hard stools may not leave the person with the sense that a full emptying has occurred. On the opposite side of the spectrum, people who suffer from chronic diarrhea may feel continued urges to defecate even after repeated bowel movements.

Why Does This Happen?

Two physiological processes have been identified as major underpinnings of IBS symptomatology and are most likely at play when it comes to the sensation of incomplete evacuation. The first, visceral hypersensitivity, refers to a heightened pain sensitivity within internal organs -- in this case, the large intestine. The second is motility dysfunction, the fact that the muscles of the large intestine do not appear to be operating in a smooth manner, thus interfering with the ability to pass a comfortable, well-formed stool.

What's Supposed to Happen

In order to begin to directly address the problem of incomplete evacuation, it is essential to know what a "complete evacuation" is supposed to be. Take a look at the picture above. Stool matter makes its way along the entire length of the large intestine. Throughout this process, water is being absorbed from the stool, so that the consistency of the stool becomes more firm as it makes its way through the bowel. Although there is a great deal of variability, typically this stool matter moves into the sigmoid colon and rectum once or twice a day. Here, it is formed into a sausage-like shape in preparation to be passed comfortably out through the anus.

Constipation researchers use a term called "complete spontaneous bowel movements" when assessing the effectiveness of a particular constipation treatment. This is the "Holy Grail" of bowel movements, sought after by IBS sufferers around the world.

Incomplete Evacuation and IBS-C

For IBS-C sufferers, the sensation of incomplete evacuation is directly related to actual physiology. Due to the difficulty in passing stool, it is likely that you have not fully emptied the rectum of stool, thus leaving you with feelings of dissatisfaction and discomfort. Obviously, the primary way to address the problem is to try treatment options for relieving the underlying constipation. Increasing fiber, whether through diet or the use of bulk laxatives, is a good way to start.

Another good self-care strategy is to ensure that you have good bowel habits. Try to schedule a trip to the toilet the same time each day. For many people, biorhythms are such that urges for bowel emptying are strongest in the morning. Allow your body the time to empty as much stool as is possible, envisioning that rectum as you evaluate the "completeness" of the movement. For further tips, see:

If you believe that dyssynergic defecation contributes to the difficulty in passing a complete stool, you may want to look into biofeedback:

Incomplete Evacuation and IBS-D

The sensation of incomplete evacuation for sufferers of IBS-D is much more complex. Although known by the blanket term tenesmus, there is a glaring lack of research on the subject when it comes to IBS-D and the occurrence of tenesmus without any overt physiological cause. Due to the lack of clinical study, the following discussion is based primarily on my own experience in consulting with IBS patients.

Given our discussion that an "ideal bowel movement" involves emptying the rectum of stool matter, then one can see that when diarrhea is experienced, there is no physiological need to keep the bowels moving to "empty" themselves. Once stool emerges that is loose and watery, any firm stool that may have been residing in the sigmoid colon has certainly been passed. Yet, the nerve and motor dysfunction inherent in IBS keeps the sensation of an urgency to empty very much alive.

In order to counteract this sense of urgency, it helps to remind yourself that no further stool really needs to come out. This type of thinking is often in direct contrast to what many IBS-D patients believe -- that emptying the bowels completely will prevent further diarrhea episodes. In fact, once the stool that is emerging is loose and watery, it is better to imagine the stool remaining in the rectum, where water can be drawn out so that the stool will be firmed up for tomorrow's bowel movement. Keep in mind that there is no such thing as a truly empty bowel, as new stool is constantly being produced. In terms of the fear of future diarrhea episodes, remember that it is easier for the muscles of the anus to contain stool that is firm (i.e., has been "hanging out" and dried in the colon), than the watery stool that is emerging from higher up in the large intestine. For further information, see:

In response to urges to continue to empty, try the use of delay. Sit quietly in a spot near the bathroom and see if you can use relaxation exercises to calm your body until the sense of urgency passes without having to make another trip to the bathroom.

Based on conversations with many IBS-D patients, I have come to believe that for some people, the repeated bathroom trips share the same underlying problem as that of the compulsions seen in obsessive compulsive disorder (OCD). Underlying anxiety strengthens the feeling of incomplete evacuation and thus the urge to engage in the emptying. The behavior of repeated bathroom trips then reinforces or strengthens the anxiety. I would love to see someone do research on this. If you believe that anxiety/compulsion might be contributing to your symptoms, you might want to consult with a behavior therapist who specializes in the treatment of OCD.

Sources:

Delvaux, M. Role of visceral sensitivity in the pathophysiology of irritable bowel syndrome Gut 2002 51:i61-i67.

American Psychiatric Association. "Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text revision" 2000. Washington, D.C.

Lund, C. Motility disorders in the irritable bowel syndrome. Gastroenterology Clinics of North America 1991 20:279-295.

DISCLAIMER: The information contained on this site is for educational purposes only and should not be used as a substitute for diagnosis or treatment rendered by a licensed physician. It is essential that you discuss with your doctor any symptoms or medical problems that you may be experiencing.

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