William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Constipation facts
- What is constipation?
- What causes constipation?
- Medications that cause constipation
- Other causes of constipation
- What are constipation symptoms?
- How is constipation diagnosed (evaluated)?
- Exams and tests
- Imaging studies and other tests
- What treatments are available for constipation?
- Dietary fiber and bulk-forming laxatives to treat constipation
- Other laxatives to treat constipation
- Other laxatives and OTC products to treat constipation
- Prescription drugs to treat constipation
- Other treatments for constipation
- What is the approach to the evaluation and treatment of constipation?
- When should I seek medical care for chronic constipation?
- What is new in the treatment of constipation?
- Pictures of Constipation Myths and Facts - Slideshow
- Pictures of Irritable Bowel Syndrome (IBS) - Slideshow
- Pictures of What's Causing Your Pelvic Pain - Slideshow
Other causes of constipation
Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (for example, when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
One suspected cause of severe constipation is the over-use of stimulant laxatives (senna [Senokot], castor oil, and many herbs). An association has been shown between the chronic use of stimulant laxatives and damage to the nerves and muscles of the colon, possibly resulting in constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormones can affect bowel movements. For example:
- Too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation.
- At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem.
- High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon
There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon can decrease the flow of stool.
Central nervous system diseases
Colonic inertia is a condition in which the nerves or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia also may be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause for constipation.
Pelvic floor dysfunction
Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
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