Define Rectal Prolapse. Describe its types, aetiology, clinical features and management.

The Concept

Rectal prolapse is the protrusion of the rectum through the anus. The essential distinction — which determines both the causes and the treatment — is between a partial (mucosal) prolapse, in which only the rectal mucosa protrudes, and a complete (full-thickness) prolapse (procidentia), in which the entire thickness of the rectal wall comes down through the anus.

Types

• Partial (mucosal) prolapse — only the mucosa protrudes, showing radial folds; common in children and the elderly.
• Complete (full-thickness) prolapse — procidentia — all layers of the rectal wall protrude, showing concentric (circular) rings of mucosa; typically in elderly women.
• Internal intussusception — an 'occult' prolapse that does not appear externally.

Aetiology

In children, prolapse is associated with straining, diarrhoea, malnutrition and cystic fibrosis, and is usually self-limiting. In adults, it results from a weak pelvic floor and anal sphincter, chronic straining, multiparity, and increasing age (hence its predominance in elderly women), sometimes with neurological disease.

Clinical Features

Patients describe a mass protruding on defecation or straining (which reduces spontaneously or must be pushed back), with mucus discharge, bleeding, faecal incontinence (from a stretched sphincter), constipation, and ulceration of the exposed mucosa. On examination the patient is asked to strain to demonstrate the prolapse, and concentric rings (complete) are distinguished from radial folds (partial); digital examination assesses sphincter tone.

Management

• Children — usually conservative: treat the underlying cause (constipation, nutrition, cystic fibrosis), with digital reduction; it typically resolves.
• Adults — surgical repair, by an abdominal approach (rectopexy — fixing the rectum to the sacrum, ± resection, often laparoscopic) for fitter patients, or a perineal approach (Delorme's or Altemeier's procedure) for the frail elderly; constipation is also treated.

A Note on Associated Pelvic-floor Problems

Full-thickness rectal prolapse in adults is often the visible tip of a wider pelvic-floor weakness, and may coexist with other prolapses (such as a cystocele or uterine/vaginal prolapse) and with faecal incontinence or obstructed defecation. This is why assessment may include examination of the whole pelvic floor and investigations such as defecating proctography or anorectal physiology, and why management sometimes involves a coordinated approach to several pelvic-floor problems rather than the rectum alone.

Abdominal VS Perineal Repair

The choice between abdominal and perineal repair is a practical, examinable decision. Abdominal rectopexy (increasingly laparoscopic) fixes the rectum to the sacrum and has the lowest recurrence rate, making it preferred in fitter patients. Perineal procedures (Delorme's, Altemeier's) avoid an abdominal operation and general anaesthetic stress, so they suit the frail, elderly or high-risk patient, but have a somewhat higher recurrence rate. The decision balances durability against operative fitness.

A Note on the Solitary Rectal Ulcer Syndrome

Related to the straining and internal intussusception that underlie prolapse is the solitary rectal ulcer syndrome — a condition in which chronic straining and internal prolapse cause an ulcer (or ulcers) on the anterior rectal wall, presenting with bleeding, mucus, straining and a sense of incomplete evacuation. It is important because it can be mistaken for malignancy or inflammatory bowel disease and needs biopsy to confirm; treatment addresses the underlying disordered defecation (biofeedback, bulking agents) rather than the ulcer itself.

A Note on Reducing an Irreducible Prolapse

An acute clinical scenario is the irreducible (incarcerated) full-thickness prolapse, in which the protruded rectum becomes oedematous and cannot be reduced, risking ulceration and, rarely, strangulation. Initial management is gentle manual reduction aided by measures that reduce the oedema (such as applying granulated sugar, which draws out fluid osmotically, then steady pressure). If reduction fails or the bowel is compromised, emergency surgery is required. Recognising and promptly reducing an incarcerated prolapse prevents progression to strangulation.

• Partial (mucosal, radial folds — children/elderly) vs complete (full-thickness procidentia, concentric rings — elderly women).
• Children: conservative (treat constipation, nutrition, cystic fibrosis); usually resolves.
• Adults: surgery — abdominal rectopexy (± resection) or perineal Delorme's/Altemeier's for the frail.

The direction of the mucosal folds distinguishes the two.

• Rectal prolapse = protrusion of the rectum through the anus; partial (mucosal only) vs complete (full-thickness, procidentia).
• Partial: radial folds, children/elderly; complete: concentric rings, elderly women; also occult internal intussusception.
• Children: straining, diarrhoea, malnutrition, cystic fibrosis; adults: weak pelvic floor/sphincter, chronic straining, multiparity, age.
• Protruding mass on straining, mucus, bleeding, incontinence, constipation, ulceration; ask patient to strain to demonstrate.
• Children conservative (treat cause); adults surgery — abdominal rectopexy or perineal Delorme's/Altemeier's for the frail.