CONSTIPATION
Section snippets
EPIDEMIOLOGY AND ECONOMICS
Constipation is a symptom rather than a disease and represents a subjective interpretation of a real or imagined disturbance of bowel function. Although constipation often is defined as a frequency of defecation of twice weekly or less, frequency alone is not a sufficient criterion. Most individuals who describe themselves as constipated complain of excessive straining or discomfort at defecation or the passage of hard or pellet stools, although frequency of defecation is within the normal
RISK FACTORS
The prevalence of self-reported constipation is related to age and gender. At all ages, females more often define themselves as constipated, and overall prevalence in both genders increases with age. This increase in prevalence is reflected in office visits for constipation. In men and women, there is a sharp rise in office visits for constipation after age 65.20 Some studies have shown that constipation is correlated to fewer years of education and lower socioeconomic status10 and to a
Cause
Constipation is a heterogeneous disorder that often is hypothesized to be disordered movement through the colon, anorectum, or both. Slowing of colonic transit may occur in association with many diseases or as a side effect of many drugs. The accompanying box, box list diseases and drugs associated with constipation. Diseases associated with chronic constipation include neurologic, metabolic, and endocrine disorders as well as obstructing lesions of the gastrointestinal tract.24
Colonic and Anorectal Transit
Because most
EVALUATION OF CONSTIPATION
The initial assessment incorporates a careful history with particular attention to identifying potential risk factors. This assessment includes defining the nature and duration of the complaint. It is helpful for patients to record their bowel habits and food intake in a diary for several weeks. Such information helps the physician to determine if such complaints arise from patient misconceptions concerning normal bowel habits. A recent and persistent change in bowel habits, if not associated
Flexible Sigmoidoscopy and Colonoscopy
Flexible sigmoidoscopy and colonoscopy are excellent techniques to identify lesions that narrow or occlude the bowel. Colonoscopy is preferable in patients older than age 50 and in those with anemia or hemoccult-positive stools because of the ability to identify polyps and other important but often incidental lesions.
Barium Radiographs
Barium radiographs are less costly than colonoscopy and are preferable in younger patients. Barium radiographs show the aganglionic distal bowel in classic Hirschsprung's disease
TREATMENT OPTIONS FOR UNCOMPLICATED CONSTIPATION
Patient education includes reassurance and an explanation about normal bowel habits. Efforts are made to reduce excessive use of laxatives and cathartics, to increase fluid and fiber intake, to encourage moderate exercise, and to use postprandial increases in colonic motility by instructing patients to defecate in the morning and after meals, when colonic motor activity is highest. Dietary fiber and bulk laxatives, such as psyllium, methylcellulose, and polycarbophil, together with adequate
LAXATIVES WITH ONSET OF ACTION IN 1 TO 3 DAYS
Psyllium, calcium polycarbophil, and methylcellulose are more refined and concentrated than bran but also are more expensive (Table 2). These agents should be diluted to ensure adequate mixing with food and generally are consumed before meals or at bedtime. All increase water content and bulk volume of the stool to decrease colonic transit time, increase stool weight, and improve stool consistency.
Sorbitol and lactulose are poorly absorbed sugars that are hydrolyzed, in part, to lactic, acetic,
LAXATIVES WITH ONSET OF ACTION IN 2 TO 8 HOURS
When patients fail to respond to bulk or osmotic laxatives, stimulant laxatives may be considered (see Table 2). These agents act by altering fluid and electrolyte transport, gastrointestinal motility, or both. Because stimulant laxatives may be abused, some physicians recommend that they be taken for no longer than several weeks, but this seems unduly restrictive and overestimates the danger. Continuous daily use of stimulant laxatives may produce diarrhea severe enough to cause hyponatremia,
PHARMACOLOGIC AGENTS
The use of drugs to promote colonic transit by increasing colonic motor activity generally has proved disappointing. Cholinergic agents have been tried with little success. Prokinetic agents, such as metoclopramide and cisapride, appear to be ineffective in most severely constipated patients.
Some patients have been treated successfully with misoprostol. Abdominal cramps have been the most limiting side effect, and the drug is not appropriate for young women who wish to become pregnant because
PROBLEMATIC PATIENT
Most chronically constipated patients do not require an extensive diagnostic workup beyond a careful history and physical examination and the appropriate exclusion of systemic or gastrointestinal causes for their complaints. Likewise, patients with constipation-predominant irritable bowel syndrome do not require extensive diagnostic testing and rarely complain of persistent constipation beyond 3 to 6 months. Evaluation of colonic and anorectal function should be reserved for patients who fail
Behavioral Approaches
Habit training has been employed successfully in children with severe constipation. The goal of such an approach is to achieve regular evacuation to prevent buildup of stool. A modified program may be effective in many adults with neurogenic constipation, patients with dementia, and patients with physical impairments.
Initially, patients should be disimpacted and the colon evacuated effectively. This evacuation can be accomplished with twice-daily enemas for 3 days. An alternative approach is to
CONCLUSIONS
Most patients with chronic constipation respond to dietary measures, fiber supplements, or laxatives. For those who do not, diagnostic tests of colonic and anorectal function help to select appropriate treatments. Therapeutic options for more severe constipation include behavioral approaches and pharmacologic agents. Surgery is a last resort and should be considered only for carefully selected patients. A stepwise approach usually results in a successful outcome in most patients.
References (32)
- et al.
Cost-effective treatment of constipation in the elderly: A randomized double-blind comparison of sorbitol and lactulose
Am J Med
(1990) Mechanisms of idiopathic constipation: outlet obstruction
Gastroenterology
(1978)- et al.
Simplified assessment of segmental colonic transit
Gastroenterology
(1987) - et al.
Psychological and physiological characteristics of patients with severe idiopathic constipation
Gastroenterology
(1989) - et al.
Segmental colonic transit time
Dis Colon Rectum
(1981) - et al.
Effect of wheat bran in treatment of chronic nonorganic constipation: A double-blinded controlled trial
Dig Dis Sci
(1995) - et al.
Selective stimulation of colonic transit by the benzofuran 5HT4 agonist, prucalopride, in healthy humans
Gut
(1999) - et al.
Clinical management of intractable constipation
Ann Intern Med
(1994) - et al.
Idiopathic megarectum in adults
Dig Dis Sci
(1995) - et al.
Colectomy for severe slow transit constipation in strictly selected patients
Scand J Gastroenterol
(1996)
Colonic and anorectal function in constipated patients with anorexia nervosa
Am J Gastroenterol
Small volume isosmotic polyethylene glycol electrolyte balanced solution (PMF-100) in treatment of chronic nonorganic constipation
Dig Dis Sci
Polyethylene glycol (PEG) laxative for ambulatory and long-term care facility constipation patients
Online J Dig Health
A longitudinal survey of self-reported bowel habits in the United States
Dig Dis Sci
Discriminant value of psychological distress, symptom profiles and segmental colonic dysfunction in outpatients with severe idiopathic constipation
Gut
A new method for studying gut transit times using radiopaque markers
Gut
Cited by (0)
Address reprint requests to Arnold Wald, MD, Division of Gastroenterology, Hepatology and Nutrition Support, University of Pittsburgh Medical Center, PUH, Mezzanine Level, C-Wing, 200 Lothrop Street, Pittsburgh, PA 15213
- *
Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition Support, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania