Before we pass stool we have a compelling urge to do so, which can last for varying periods of time. This physiological urge is what motivates a person to find a place to pass stools and assume the appropriate position to have a bowel movement. The urge to defecate is a culmination of the following physiological processes:
- The digested food moves into the colon through peristaltic action of the walls of the intestines.
- The wall of the colon is stretched as digested food waste and water accumulates in it.
- The stretch receptors present in the walls of the colon sense the expansion of the colon and trigger the defecation reflex. The defecation reflex involves contraction of the colonic muscles that facilitates movement of the feces into the rectum, and relaxes the internal anal sphincter. This creates the compelling urge to defecate.
- Defecation is then assisted by increased abdominal pressure.
The urge to defecate subsides completely once the feces in the rectum are passed out. Depending on individual bowel habit, this urging occurs daily, usually at particular times of the day (especially morning for most people). However, the frequency varies in different persons, and ranges from a few times daily to a few times weekly. Certain conditions that stimulate this urge to defecate include:
- A large meal.
- Strong emotions and psychological stress.
- Brisk physical activity.
- Increase in abdominal pressure.
These conditions that create the urge to defecate are considered normal, even though they are not regular factors that aid everyday routine emptying of the bowels.
Read more on overactive bowels.
What is tenesmus?
Sometimes, the urge to defecate becomes abnormal. In these cases, there is an urge to empty the bowels, but very little or no stool comes out. This spurious urge to defecate is technically known as tenesmus. Tenesmus can be accompanied by pain, abdominal cramps and involuntary straining to defecate. It can continue even after a bowel movement. In these cases there is also a feeling of incomplete evacuation of the bowels.
Tenesmus is classified into two categories: intermittent and persistent. Intermittent tenesmus is characterized by a recurring urge to defecate, meaning that it comes and goes. In persistent or constant tenesmus, the urge to defecate does not subside. It can persist for long periods of time, even hours and days. Passing stool may ease it to some degree but this relief is short-lived. Despite efforts to defecate again, there is no passing out of stool.
Causes for Persistent Urge
There are a number of different causes that can lead to tenesmus. Most are directly associated with some malfunction of the colon, rectum and the anus. But some causes are due to an indirect affect on the bowels as a result of a disorder that does not involve the bowel. The constant urge to defecate is commonly associated with the following conditions:
- Constipation: Constipation is frequently associated with either constant or intermittent urge to defecate. This feeling is usually temporary. In most cases, the exact cause for constipation remains unknown.
- Hemorrhoids: Hemorrhoids, or piles, refer to inflammation and bulging of the veins in the rectum and anus. It is associated with both diarrhea and constipation. Sitting for prolonged periods in a toilet is also thought to contribute to this condition.
- Inflammatory bowel disease (IBD): Inflammatory bowel disease is the most common cause of the constant urge to defecate. As the name suggests, IBD refers to a chronic inflammation of the walls of the bowels. It is categorized into two subtypes: ulcerative colitis and Crohn’s disease.
- Irritable bowel syndrome (IBS): Irritable bowel syndrome is characterized by bouts of diarrhea and constipation. A feeling of bloating, abdominal pain and cramps are common symptoms in IBS. Irritable bowel syndrome is a functional disease, which means that despite the abnormal bowel behavior, the bowels don’t seem to show any structural abnormalities. The exact cause of IBS is not known.
- Infectious colitis: Infection of the colon, caused by bacteria, parasites, and viruses, can also cause frequent urge to defecate. The infection may even result from conditions that lead to an overgrowth of some residential bacteria in the colon.
- Abnormal growths in colon and rectum: Polyps, tumors and cancers in the colon and rectum (colorectal growths) are also associated with the constant urge to defecate.
- Inflammation of the rectum: Technically known as proctitis, inflammation of the rectum is caused by infections and injury to the rectum.
- Other colorectal problems: Other colorectal problems associated with a constant urge to defecate include fecal impaction, rectal prolapse, rectal perforation, presence of a foreign body in the rectum, obstipation, ischemic proctolitis, and perirectal abscess.
- Problems with the anus: Apart from hemorrhoids, other problems with the anus can also cause tenesmus. These include anal fissures, anal fistulas, perianal abscesses, and anal cancer.
- Problems with female reproductive system: The majority of conditions that are primarily associated with the constant urge to defecate involve problems with the colon, rectum and anus. However, due to the proximity of some structures of the reproductive system and the bowels, conditions affecting the reproductive structures may also lead to tenesmus. These conditions include endometriosis, infection of paraurethral glands, female urethral syndrome and pelvic inflammatory disease.
- Problems with male reproductive system: Tenesmus may also be caused by some conditions affecting the male reproductive system, especially the prostate. These conditions include prostate cancer and inflammation (prostatitis).
- Other causes: Some other conditions that are infrequently associated with tenesmus include overuse of laxatives and suppositories, pelvic tumors, pinworms in the intestine, and AIDS.
Read more on recurrent diarrhea.
Treatment for Tenesumus
Treating tenesmus, or the constant urge to defecate, depends on first identifying the exact cause of the feeling. The constant urge to defecate is a symptom, and not a disease by itself. As mentioned above, the underlying causes for tenesmus are diverse. Therefore, the treatments would be diverse as well. For example, in case of cancers, radiotherapy can help in alleviating tenesmus problems. Laparoscopic treatments are used for women with bowel endometriosis. Thrombosed piles may require surgical removal.
Apart from disease-specific treatments, there are some useful general measures that can help in the management of tenesmus. These include:
- Increasing fiber intake in diet and avoiding foods that result in constipation.
- Increasing the intake of water.
- Not straining hard while defecating.
- Not sitting for long in toilet.
- Increasing physical activity in order to promote healthy gut movements.
- Avoiding overuse of laxatives.