15-42: Rectal Prolapse & Solitary Rectal Ulcer Syndrome

Rectal prolapse is protrusion through the anus of some or all of the layers of the rectum. Hemorrhoidal (mucosal) prolapse is common (see discussion under Hemorrhoids). Full thickness is uncommon and is usually caused by surgical or traumatic injuries or from chronic, excessive straining at stool in conjunction with weakening of pelvic support structures, especially in patients who are older, psychotic, or paraplegic. Although prolapse initially reduces spontaneously after defecation, with time the rectal mucosa becomes chronically prolapsed, resulting in mucous discharge, bleeding, incontinence, and sphincteric damage. Patients with complete prolapse require surgical correction.

The term "solitary rectal ulcer syndrome" is a misnomer. The syndrome is characterized by anal pain, excessive straining at stool, and passage of mucus and blood. It is most commonly seen in young adults, especially women. Proctoscopic examination reveals either shallow ulcerations (single or multiple) or a nodular mass located anteriorly 6–10 cm above the anal verge. Biopsy is diagnostic. The disorder may be caused by rectal prolapse or paradoxical contractions of the pelvic floor with excessive straining during defecation. Treatment is directed at decreasing straining through education of the patient, use of bulking agents, biofeedback therapy, and surgical treatment of prolapse, when present.