Colonic Transit Time Anorectal Manometry Defecography Anorectal Manometry Psychological Profile Esophageal, gastric and small intestinal studies to evaluate for gastrointestinal pseudoobstruction Infrequent Defecation Normal Defecatory Straining Normal Outlet Delay Colonic Inertia Normal Hirschsprung Disease Anatomical Abnormalities Abnormal Expulsion Define Complaint
Figure 28.7 Diagnostic Algorithm for Idiopathic Constipation. (From Ellerkmann MR, Kaufman H. Defecatory dysfunction. In:
Bent AE, Ostergard DR, Cundiff GW, et al., eds. Ostergard’s urogynecology and pelvic ﬂoor dysfunction. 5th ed. Philadelphia,
PA: Lippincott Williams & Wilkins, 2002:358, with permission.) has fecal impaction. Symptoms that persist despite a trial of conservative management indicate the need for further evaluation of colonic and anorectal function. A diagnostic algorithm for idiopathic (nonsystemic) constipation is given in Figure 28.7. Treatment should then be tailored to the underlying cause. Some conditions associated with disordered defecation are best treated using nonsurgical techniques, whereas others may benefit from surgery once conservative management has failed. As with fecal incontinence, the lack of consistent outcome measures in the published literature makes it difficult to compare efficacy among treatments.
in adults with constipation (156). This study lacked baseline data collection resulting in recall bias, and the use of mineral water containing magnesium may confound the results because of its mild laxative effect. Overall, the existing data do not support increased ﬂuid intake to treat constipation unless there is evidence of dehydration (151).
The addition of fiber may decrease constipation through several mechanisms. Fiber acts as a stool bulking agent and improves stool consistency through water absorption. It can also act as a substrate for bacterial proliferation and gas production. These mechanisms of action are believed to result in increased colonic motility, decreased transit time, and increased stool frequency.
Fiber therapy appears to have a beneficial effect in the treatment of diverticular disease, constipation of pregnancy, and possibly IBS (19,157,158). Its efficacy for idiopathic (nonsystemic) constipation remains uncertain. Dietary fiber intake for patients with constipation was similar to that of controls in several studies (152,153). A meta-analysis of 36 randomized trials using laxatives or fiber therapy for the treatment of constipation showed that the use of fiber or laxatives resulted in increased stool frequency and improved symptoms without the presence of severe side effects (159). Conversely, another meta-analysis showed an inability to restore transit time and stool weight in constipated patients using dietary fiber (158). Approximately half of the patients in another study responded to fiber treatment, but a much better response occurred in patients without an identifiable structural or motility disorder (160). Consequently, a low-fiber diet may be a contributing factor in chronic constipation, and an empiric trial of fiber therapy can be expected to help some patients. Side effects of increased gas production may limit compliance with treatment, so doses should be slowly titrated. Fiber therapy should be avoided in patients with impaction, megacolon or megarectum, or obstructive gastrointestinal lesions. Fiber therapy should also be used with caution in patients with cognitive dysfunction (dementia), difficulty with ambulation, and underlying neurogenic disease for fear of worsening the condition. There is no evidence to substantiate the recommendation for extra water intake with fiber supplements (161).
Laxatives are commonly used to treat constipation and disordered defecation. Many classes of laxatives are available over the counter.