Constipation: Evaluation and Management

Abstract

Constipation is defined as the infrequent passage of stools or difficulty with evacuation of stools. Constipation can be classified as primary or secondary, and primary constipation can be further divided into slow transit constipation or outlet obstruction. The diagnostic workup involves focused lab tests and structural evaluation, followed by a therapeutic trial of fiber and laxatives, and finally, specialized tests. Treatment can consist of dietary changes, medications, physical therapy, and possibly surgery in refractory cases.

Figure 1

Diagnostic algorithm for constipation *Normal or negative manometry study is normal balloon expulsion with no paradoxical contraction **Inconclusive manometry is normal balloon expulsion and paradoxical contraction OR abnormal balloon expulsion and no paradoxical contraction ***Abnormal or positive manometry is abnormal balloon expulsion and paradoxical contraction

Figure 2

High resolution anorectal manometry. A catheter with multiple pressure transducers is introduced through the anal canal and into the rectum and provides real-time pressure measurements at the external anal sphincter, internal anal sphincter and within the rectum. The patient is asked to try to expel the catheter by increasing intraabdominal pressure and relaxing the external sphincter. as shown in this example, two attempts to expel the catheter (from 3 to 11 seconds and 34 to 42 seconds) resulted in appropriately increased intraabdominal pressure but dyssynergic contraction of the external sphincter and no relaxation of the internal sphincter. The color pressure scale is shown on the right from low pressure (blue) to high pressure (red).

Figure 3

Treatment algorithm for functional constipation. Once secondary constipation has been excluded and functional constipation has been characterized, treatment can be focused on the underlying disorders.