13 Dias

The

new england journal

of

medicine

review article

current concepts

Chronic Constipation
Anthony Lembo, M.D., and Michael Camilleri, M.D.
From the Gastroenterology Division, Beth Israel Deaconess Medical Center, Boston (A.L.); and the Gastroenterology Division, Mayo Clinic, Rochester, Minn. (M.C.). Address reprint requests to Dr. Lembo at the Gastroenterology Division, BethIsrael Deaconess Medical Center, Dana 501, 330 Brookline Ave., Boston, MA 02215, or at alembo@bidmc.harvard.edu. N Engl J Med 2003;349:1360-8.
Copyright © 2003 Massachusetts Medical Society.

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onstipation is a common symptom affecting between 2 percent1,2 and 27 percent3 of the population in Western countries. In the United States, it results in more than 2.5 million visits to physicians,92,000 hospitalizations,2 and laxative sales of several hundred million dollars a year. Constipation is more prevalent in women than in men,4 in nonwhites than in white persons,5 in children than in adults,6 and in elderly than in younger adults.5 Severe constipation (e.g., bowel movements only twice a month) is seen almost exclusively in women.4 Physical inactivity, low income, limited education, ahistory of sexual abuse, and symptoms of depression are all risk factors for constipation.7 Though the symptoms associated with constipation are often intermittent and mild, they may be chronic, difficult to treat, and debilitating. This review focuses on the evaluation and treatment of patients whose constipation is chronic and severe and does not resolve with the use of simple dietary ortherapeutic measures. An understanding of the physiological processes involved in colonic transit and defecation is important for the effective management of constipation.

definition
There is no single definition of constipation. Most patients define constipation by one or more symptoms: hard stools, infrequent stools (typically fewer than three per week), the need for excessive straining, a sense ofincomplete bowel evacuation, and excessive time spent on the toilet or in unsuccessful defecation.8,9 An epidemiologic study of constipation in the United States identified it as an inability to evacuate stool completely and spontaneously three or more times per week.1 A consensus definition of constipation (the Rome II criteria), used in current research, is shown in Table 1.10
causes andpathophysiology

Constipation is frequently multifactorial and can result from systemic or neurologic disorders or medications. Constipation can be classified into three broad categories: normal-transit constipation, slow-transit constipation, and disorders of defecatory or rectal evacuation. More than one mechanism may contribute to constipation in a patient. In a study of more than 1000 patientswith chronic constipation, normal transit through the colon was the most prevalent form (occurring in 59 percent of the patients), followed by defecatory disorders (25 percent), slow transit (13 percent), and a combination of defecatory disorders and slow transit (3 percent).6
Normal-Transit Constipation

Normal-transit constipation (or “functional” constipation) is the most common form ofconstipation that clinicians see. In patients with this disorder, stool traverses at a normal rate through the colon and the stool frequency is normal, yet patients believe they are constipated.11 In this group of patients, constipation is likely to be due to a perceived difficul-

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current concepts

ty with evacuation or the presence of hard stools. The patients may experience bloating and abdominal pain or discomfort, and they may exhibit increased psychosocial distress11; some may have increased rectal compliance, reduced rectal sensation, or both.12 Symptoms of constipation...