Introduction

The principal functions of the colon and rectum are storing fecal waste for prolonged periods and expelling it appropriately. Storage is facilitated by adaptive compliance of the intestine and by contractions of colonic smooth muscle, which slow the movement of stool, thereby promoting water absorption and reducing stool volume. Stool moves by relatively infrequent peristaltic contractions. Defecation and continence are maintained by the ability to sense rectal filling and by the coordinated function of the internal and external anal sphincters and the pelvic floor muscles.

Colonic motility and transit in healthy elderly persons are similar to those in younger persons; however, aging is associated with diminished anal sphincter tone and strength and decreased rectal compliance. The latter may increase susceptibility to fecal incontinence in the elderly.

The major symptoms of lower gastrointestinal (GI) disorders are constipation, diarrhea, pain, rectal bleeding, and fecal incontinence. Lower GI disorders that occur more commonly in the elderly than in younger persons are diverticular disease, angiodysplasia, colonic ischemia, antibiotic-associated diarrhea and colitis, fecal incontinence, and constipation. Inflammatory bowel diseases occur in all age groups, but new onset is more likely in the elderly and in persons in their 20s.