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Definition: constipation from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

In medicine, the infrequent emptying of the bowel. The intestinal contents are propelled by peristaltic contractions of the intestine in the digestive process. The faecal residue collects in the rectum, distending it and promoting defecation. Constipation may be due to illness, alterations in food consumption, stress, or as an adverse effect of certain drugs. An increased intake of dietary fibre (see fibre, dietary) can alleviate constipation. Laxatives may be used to relieve temporary constipation but they should not be used routinely.


Summary Article: Constipation from Encyclopedia of Lifestyle Medicine and Health

Approximately 2.5 million physician visits every year can be attributed to complaints of constipation, and more than 4 million Americans are believed to have frequent constipation, one of the most common gastrointestinal complaints in the United States. Almost everyone experiences this ailment at some point in his or her life. Given the widespread impact of constipation, it is essential for those with this condition to understand the causes and treatment options available.

Population-based studies show that constipation is more commonly reported by women than by men and is most common in adults aged 65 years and older. Nonwhites and those with low socioeconomic status and/or limited education are other groups that are associated with a higher incidence of constipation.

Definition

Constipation is a term that refers to a disturbance in bowel function resulting in infrequent stools (generally fewer than 3 stools per week) or difficulty with defecation. No single definition of chronic constipation exists however, it is generally described as constipation of more than 12 weeks that does not respond to dietary fiber or simple therapeutic measures. An international working committee developed diagnostic criteria, known as the Rome III criteria, to promote consistency in the diagnosis of chronic constipation.

Based on the Rome III criteria, the diagnosis should be based on the presence of the following for at least 3 months (with symptom onset at least 6 months prior to diagnosis):

  1. They must include 2 or more of the following.

    • Straining during at least 25% of defecations

    • Lumpy or hard stools in at least 25% of defecations

    • A sensation of incomplete evacuation for at least 25% of defecations

    • A sensation of anorectal obstruction/blockage for at least 25% of defecations

    • Manual maneuvers to facilitate at least 25% of defecations (e.g., digital evacuation, support of the pelvic floor)

    • Fewer than 3 defecations per week

  2. Loose stools are rarely present without the use of laxatives.

  3. There are insufficient criteria for a diagnosis of irritable bowel syndrome.

A review of epidemiological studies found that estimates of the prevalence of constipation in the United States vary from 2% to 28%, most likely because no standard definition of constipation exists.

Causes and Contributing Factors

Constipation generally occurs because the colon absorbs too much water from food moving through it. If the colon's muscle contractions are slow, food may move through it too slowly, allowing the colon to absorb an excess of water. As a result, stools can become hard and dry.

Idiopathic constipation refers to constipation that is from an unknown cause. Functional constipation can be classified as slow transit, pelvic floor dysfunction, or a combination of both. Decrease in muscle activity in the colon or uncoordinated motor activity causes slow-transit constipation, whereas pelvic floor dysfunction is caused by a weakness of the muscles in the pelvis surrounding the anus and rectum. Anorectal dysfunction, or anismus, is a form of functional constipation caused by abnormalities in the structure of the anus or rectum. This results in an inability to relax the muscles that allow stool to exit.

Those with constipation generally find it painful to have a bowel movement and experience straining, bloating, and the uncomfortable sensation of a full bowel. Most constipation is temporary and not serious. Sometimes, however, constipation can lead to serious complications when left untreated. Examples of such complications include hemorrhoids and anal fissures caused by straining to have a bowel movement. Moreover, this straining effort can cause a small portion of the intestinal lining to be pushed through the anal opening (rectal prolapse), a condition that may require surgical correction. Constipation may result in fecal impaction, wherein the normal movement of the bowel is not sufficient to expel the stool. Fecal impaction may require administration of an enema and/or manual disimpaction.

Prior to treatment, secondary causes of constipation should be evaluated. Medications such as opioids, anticholinergics (antihistamines, antispasmodics, antidepressants, and antipsychotics), anticonvulsants, calcium channel blockers, chemotherapy agents, anti-Parkinson's agents, calcium supplements, aluminum-containing antacids, and iron supplements are often found to cause constipation. Overuse of laxatives may cause the body to become dependent on the use of the laxative in order to have a bowel movement. In addition, medical conditions such as diabetes, colon cancer, multiple sclerosis, Parkinson's disease, anorexia, and pregnancy can cause constipation. Lifestyle factors such as poor diet, inadequate fluid intake, and lack of exercise can also be contributing factors.

Prevention and Treatment

First-line options for the treatment of constipation include lifestyle modifications such as increased dietary fiber and fluid intake and regular physical activity. Fiber helps alleviate constipation by binding water in the gastrointestinal tract, reducing colonic transit time, and increasing stool bulk and frequency. Increased dietary fiber can be achieved by consuming more fruits, vegetables, and whole grains. The American Dietetic Association recommends that women consume 20 g and men 38 g of fiber per day. Most Americans fall short of this recommendation and consume less than 15 g/d. Avoiding dehydration by increasing fluids such as water and juice can help relieve constipation. The data showing a direct effect of these interventions on constipation are not strong however, they have shown benefit in lowering the risk of various diseases and conditions that can cause constipation.

When lifestyle modifications are not effective in relieving constipation, it may be appropriate to consider using over-the-counter products such as stool softeners, hyperosmolar agents, fiber/bulk-forming laxatives, stimulant laxatives, saline laxatives, or lubricant laxatives. Finally, there are prescription medications available for the treatment of constipation, such as the chloride channel activator lubiprostone.

Further Readings
  • Bleser, S; Brunton, S; Carmichael, B; Olden, K; Rasch, R; Steege, J Management of chronic constipation: recommendations from a consensus panel. J Fam Pract. 54 : 691-698.
  • Brandt, LJ; Prather, CM; Quigley, EM; Schiller, LR; Schoenfeld, P; Talley, N Systematic review on the management of chronic constipation in North America. Am J Gastroenterol. 100 (suppl 1): S1-S4.
  • Higgins, PD; Johnson, JF Epidemiology of chronic constipation in North America: a systemic review. Am J Gastroenterol. 99 : 750-759.
  • Longstreth, GF; Thompson, WG; Chey, WD; Houghton, LA; Mearin, F; Spiller, RC Functional bowel disorders. Gastroenterology. 130 (5): 1480-1491.
  • Marlett, JA; McBurney, MI; Slavin, JL Position of the American Dietetic Association: health implications of dietary fiber. J Am Diet Assoc. 108 : 1716-1731.
  • National Digestive Diseases Information Clearinghouse. Constipation. http://digestive.niddk.nih.gov/ddiseases/pubs/constipation. Accessed October 17, 2008.
  • Hartman, Sarah
    MacKenzie, Elizabeth
    opyright © 2012 by SAGE Publications, Inc.

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