Prolaps Rekti

01Pathophysiology

Rectal prolapse (procidentia) occurs when the full thickness of the rectal wall descends through the anal canal and protrudes externally. The underlying mechanism involves a combination of weakened pelvic floor support and loss of the normal posterior fixation of the rectum to the sacrum. Over time, chronic straining, multiparity, or age-related connective tissue degeneration leads to laxity of the lateral ligaments, levator ani muscles, and the rectosacral fascia. This allows the rectum to intussuscept into itself and eventually telescope out through the anus.

The deep pouch of Douglas is a key anatomical finding. In patients with prolapse, this peritoneal pouch extends abnormally low along the anterior rectal wall, creating a sliding hernia that drags the rectum downward during Valsalva. The redundant sigmoid colon acts as a lead point for intussusception. As the rectum repeatedly protrudes, the internal anal sphincter becomes chronically stretched, which explains why patients develop progressive fecal incontinence and decreased resting anal tone.

In children, rectal prolapse is most commonly associated with cystic fibrosis due to chronic coughing, malnutrition, and bulky stools. In fact, any child presenting with rectal prolapse should prompt a sweat chloride test to rule out cystic fibrosis. In adults, the condition overwhelmingly affects elderly multiparous women, making pelvic floor laxity the dominant mechanism.

Mucosal discharge and bleeding result from chronic exposure and trauma to the prolapsed rectal mucosa, which becomes congested, edematous, and ulcerated over time. Constipation may be both a cause and a consequence: straining promotes prolapse, while prolapse creates a functional outlet obstruction that worsens straining.

02Classification and Clinical Manifestation

The single most important distinction for exam purposes is differentiating mucosal prolapse from full-thickness prolapse. Mucosal prolapse shows radial folds (like spokes of a wheel) because only the loosely attached mucosa slides out. Full-thickness prolapse shows concentric rings (circular folds) because all layers of the rectal wall, including the muscularis, are involved. This finding is the classic discriminator on the exam.

03Diagnostic Workup

The diagnosis of full-thickness external rectal prolapse is clinical. If the patient can reproduce the prolapse by straining on the commode or in the left lateral decubitus position, no further imaging is needed to confirm the diagnosis. The examiner should observe the perineum during straining and look for the classic concentric rings.

When the patient describes symptoms consistent with prolapse but nothing is visible on exam, the diagnosis of internal (occult) prolapse should be suspected. In this setting, defecography becomes the most accurate test. It captures real-time imaging during defecation and demonstrates the intussusception that cannot be seen externally.

Anal manometry is not used for diagnosis but is important preoperatively. It helps the surgeon counsel the patient regarding expected continence outcomes after repair. If sphincter pressures are severely diminished, the patient may remain incontinent even after anatomical correction, and adjunctive sphincter repair or biofeedback may be needed.

04Management and Treatment

Acute stabilization: When a patient presents with an incarcerated prolapse that cannot be reduced, the first step is to reduce the edema. Applying granulated sugar (osmotic agent) to the exposed mucosa for 15 to 20 minutes draws out interstitial fluid and shrinks the tissue, allowing gentle manual reduction. If reduction is successful, the patient should be scheduled for elective definitive repair. If the prolapsed segment is gangrenous or irreducible, emergent operative intervention is required.

Definitive surgical management depends on patient fitness. For patients who can tolerate general anesthesia, the abdominal approach is preferred. Posterior suture rectopexy (or mesh rectopexy, such as the ventral mesh rectopexy popularized in Europe) fixes the rectum to the presacral fascia, restoring normal posterior attachments. When constipation is the dominant symptom, a sigmoid resection is added (resection rectopexy) to remove the redundant colon and improve transit time.

For elderly or medically frail patients, perineal procedures are favored because they avoid laparotomy and general anesthesia. The Altemeier procedure (perineal rectosigmoidectomy) involves full-thickness excision of the prolapsed segment with a primary coloanal anastomosis and levatorplasty. The Delorme procedure involves stripping the mucosa off the prolapsed segment and plicating the exposed muscularis. Perineal approaches carry higher recurrence rates but are well tolerated in patients with significant comorbidities.

In children, rectal prolapse is nearly always managed conservatively first. Manual reduction, dietary fiber, stool softeners (polyethylene glycol 0.5 to 1 g/kg/day), and treatment of the underlying condition (such as cystic fibrosis) resolve most cases. Surgical intervention is reserved for the rare child with persistent prolapse beyond age 3 to 4 years.

A contraindication worth noting: mesh rectopexy should be used cautiously in patients who may require future pelvic surgery or in the setting of contamination, as mesh infection and erosion are recognized complications.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most commonly tested concept with rectal prolapse is the ability to differentiate it from prolapsed hemorrhoids. Expect a vignette describing an elderly woman with a protruding anal mass on straining. The exam will hinge on whether the mucosa shows concentric rings (full-thickness prolapse) or radial folds (mucosal/hemorrhoidal prolapse). Selecting hemorrhoidectomy for a patient with full-thickness rectal prolapse, or vice versa, is the classic trap.

A second high-yield pearl involves the pediatric patient. When a child younger than 3 years presents with rectal prolapse, the expected next step is a sweat chloride test to evaluate for cystic fibrosis. Failing to associate rectal prolapse in children with cystic fibrosis is a frequently missed connection.

On the management side, test-writers commonly assess whether you know the surgical approach stratified by operative risk. A young, healthy patient should receive an abdominal rectopexy. An 85-year-old with heart failure and rectal prolapse should receive a perineal procedure. Choosing the wrong approach for the wrong patient is a predictable wrong-answer trap. Similarly, the acute management pearl of using granulated sugar to reduce an edematous incarcerated prolapse is a classic "what is the next best step" question.

Finally, remember that rectal prolapse and fecal incontinence are tightly linked. Anatomical repair corrects the prolapse but does not always restore continence, because the sphincter may be irreversibly damaged from chronic stretch. Postoperative continence improvement depends on preoperative sphincter function, which is why anal manometry matters before surgery.