New Colonoscopy Guidelines for Adults with Frequent Constipation
By David S. MacDougall
OAK BROOK, Ill—The American Society of Gastrointestinal Endoscopy released new clinical guidelines for the use of endoscopy in patients with chronic constipation, which is associated with an increased risk of colorectal cancer (odds ratio, 2.36). Thus, colonoscopy is recommended in all persons aged ³50 years who have not undergone previous colorectal cancer screening.
The guidelines, which were published in Gastrointestinal Endoscopy(2005;62:199-201), indicate that constipation affects up to 27% of the US adult population and results in about 2.5 million physician office visits each year. Risk factors for constipation include female gender, low socioeconomic status, physical inactivity, depression, and a history of sexual abuse.
According to the guidelines’ authors, data from well-designed, prospective trials evaluating the role of gastrointestinal endoscopy in patients with constipation are limited. These new guidelines are based on a critical review of published literature, anecdotal reports from recognized authorities, and the consensus recommendations of a panel of experts.
Constipation is defined in these guidelines according to the Rome II diagnostic criteria (Table). Accordingly, physicians should consider the diagnosis in patients with a normal frequency of defecation who complain of excessive straining, discomfort, or passage of hard stools.
Colonoscopy is generally recommended for use in select patients to exclude the presence of obstruction from cancer, stricture, or extrinsic compression. Potential indications for colonoscopy in patients with constipation are listed in Table 2.
The diagnostic yield of colonoscopy in patients with constipation may be limited. “The yield of colonoscopy in isolated constipation is low and is comparable with asymptomatic patients who undergo colonoscopy for colon cancer screening,” the authors state.
In a study of 563 sigmoidoscopies or colonoscopies performed for evaluation of constipation, colorectal cancer was detected in 1.4%, adenomas in 14.6%, and advanced lesions in 4.3% of cases.
Colonoscopy may be used to guide therapy in select patients, the guidelines suggest, including dilation of fibrotic strictures from surgery or inflammatory bowel disease. Colonoscopy is not recommended for therapeutic use in patients with stool impaction.
Contraindications to colonoscopy in patients with constipation include complete or high-grade colonic obstruction or suspected perforation. Potential contraindications include acute inflammation of the colon, advanced pregnancy, recent myocardial infarction, pulmonary embolism, large aortic aneurysm, and an uncooperative patient.
Chronic constipation, the authors note, is an independent risk factor for inadequate bowel preparation for colonoscopy. Therefore, a more aggressive bowel cleansing should be considered before the use of colonoscopy in a patient with chronic constipation.
Table 1. Rome II diagnostic criteria for functional constipation
At least 12 weeks of the preceding 12 months with ³2 of the following:
Source: Gastrointestinal Endoscopy. 2005;62:199-201.
Table 2. Indications for colonoscopy in patients with constipation
Source:Gastrointestinal Endoscopy. 2005;62:199-201.