Pediatric Rectal Prolapse

Updated: Sep 19, 2016
  • Author: Jaime Shalkow, MD, FACS; Chief Editor: Carmen Cuffari, MD  more...
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Overview

Background

Although less common in Western societies, pediatric rectal prolapse is a relatively common benign disorder in children. However, without proper treatment, it can become a lifestyle-limiting, chronic condition. Most cases are self-limiting, characterized by prompt resolution with institution of conservative measures aimed at correcting associated underlying problems.

In the pediatric population, rectal prolapse should always be considered as a presenting sign of an underlying condition and not a discrete disease entity unto itself.

Rectal prolapse in children is thought to begin as mucosal prolapse starting at the mucocutaneous junction, which may eventually progress to full-thickness prolapse.

Prolapse of the rectum is one of the first surgical entities described in the medical profession. It can be defined as the protrusion of a few or all layers of the rectal wall through the anal sphincter (see the image below).

Image of young patient with full-thickness rectal Image of young patient with full-thickness rectal prolapse with multiple circular folds seen on exposed mucosa.

Rectal prolapse and its etiology were first described in 1912 by Moschcowitz. Rectal prolapse in childhood was first highlighted in 1939 by Lockhart-Mummery, [1] who attributed the condition to malnutrition and careless nursing, but also acknowledged diarrheal and wasting illnesses as contributing factors. Lockhart-Mummery’s preferred operative treatment was linear cauterization of the prolapsed rectum, with recurrences treated by 5% phenol injection.

Loss of the normal sacral curvature that causes a vertical tube between the rectum and the anal canal has been described as a causative factor. Straining during defecation predisposes children with constipation, diarrhea, or parasitosis to prolapse, as does childhood laxative usage. About 60-70% of patients have fecal incontinence. [2] The prolapse can spontaneously reduce or it can be digitally reduced.

One classification of rectal prolapse divides the entity into true prolapse (protrusion of all layers of the rectum) and procidentia (herniation of only the mucosa). However, this classification is confusing and nonspecific and therefore, should be abandoned.

The classification most widely used currently for rectal prolapse was described in 1971 by Altemeier et al, who divided the entity into the following 3 types [3] :

  • Type I - Protrusion of redundant mucosa, termed false prolapse; it is usually associated with hemorrhoids
  • Type II - Intussusception without sliding hernia of the cul-de-sac; it occupies the rectal ampulla but does not continue through the anal canal; the most common symptom is fecal incontinence, but solitary ulcers in the anterior rectal mucosa can be seen
  • Type III - Complete prolapse, including full-thickness rectal wall prolapse; it is associated with a sliding hernia of the Douglas pouch and is the most frequent type
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Anatomy

The anal canal extends cephalad from the anal verge to the anorectal ring. The rectum extends from this point to the sacral promontory.

Upon histologic examination, the anal canal consists of mucosa, submucosa, and 2 muscular layers: the internal anal sphincter (IAS), which is a continuation of the circular muscle of the rectum, and (2) the external anal sphincter (EAS), which lies outside the IAS as an elliptic cylinder and is continuous with the puborectalis muscle superiorly. The surgical anal canal includes this entire muscular sphincter mechanism (see the images below).

Levator ani muscle is shown in red. It includes il Levator ani muscle is shown in red. It includes ileococcygeus (stretches during defecation and labor), pubococcygeus (maintains integrity of pelvic floor), and puborectalis (closes anorectal canal as sling) muscles.
Deep, superficial, and subcutaneous external sphin Deep, superficial, and subcutaneous external sphincter.
Anatomy of internal and external anal sphincter me Anatomy of internal and external anal sphincter mechanisms.

The many and varied procedures described for the treatment of rectal prolapse attempt to create a fixation of the anorectal mucosa to the submucosa, or the rectal wall to perirectal tissues.

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Pathophysiology

A pelvic floor defect with levator ani muscle diastasis and a deep endopelvic fascia have been described as a pathophysiologic effect for the disease. Patients with rectal prolapse have lost the normal semihorizontal rectal position; they also have weak muscle insertions to the pelvic walls and sacrum and an abnormally deep Douglas pouch. A redundant rectosigmoid and a weaker and wider anal sphincter are common.

The normal resting tone of the anal sphincter decreases in response to rectal distention. In 1962, Porter found that patients with rectal prolapse have a profound and lengthy response and weakened tone of the levator ani muscles. [4] Whether this is a causative factor or a secondary finding is not clear, because the prolapse begins above the pelvic musculature.

Rectal prolapse has been associated with myriad conditions, including the following:

  • Increased intra-abdominal pressure due to straining (as often occurs in toilet training and constipation)
  • Parasitic disease (eg, trichuriasis, or whipworm) and neoplastic disease
  • Malnutrition (loss of ischiorectal fat pad) - Worldwide, this is possibly the most common condition associated with pediatric rectal prolapse; the loss of ischiorectal fat reduces perirectal support
  • Meningomyelocele
  • Surgical repair of an anorectal malformation
  • Fecal incontinence and diarrhea [5, 6]
  • Chronic constipation [7]
  • Neuromuscular disorders
  • Mental challenge [8]
  • Poor sacral root innervation (as observed in patients with spina bifida)
  • Bladder or cloacal exstrophy [9]
  • Scleroderma [10]
  • Hirschsprung disease (especially in the ultrashort aganglionic segment, which acts as a subocclusion, favoring the appearance of rectal prolapse) [11]
  • Rectal polyps (in which the polyp acts as a leading point for the intussusception) [12]
  • Shigellosis in neonates [14]

Cystic fibrosis deserves special attention; rectal prolapse is found in 20% of patients with cystic fibrosis and is the presenting symptom in one third of them. Potential mechanisms by which this condition predisposes an individual to prolapse include bulky bowel movements, coughing paroxysms, and undernutrition. [15, 16]

Other implicated entities include lymphoid hyperplasia of the distal colon, which also acts as a leading point for rectal intussusception, [17] parasites and other infectious agents, [14, 18, 19] and HIV infection. [20]

Most cases of childhood rectal prolapse occur in children younger than 4 years, with the highest incidence during the first year of life. Anatomic considerations related to this early presentation include the vertical course of the rectum along the straight surface of the sacrum, a relatively low position of the rectum in relation to other pelvic organs, increased mobility of the sigmoid colon, relative lack of support by the levator ani muscle, loose attachment of the rectal mucosa to the underlying muscularis, and absence of Houston valves seen in about 75% of infants.

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Etiology

The exact etiology of rectal prolapse in children is unknown. However, several predisposing factors have been identified. The most common underlying condition is chronic constipation and straining (52%).

Other causes include diarrhea (15%), [5] rectal parasites [21] (the most common cause of rectal prolapse in developing countries), neuromuscular and pelvic nerve disorders, myelomeningocele, bladder and cloacal exstrophy, Hirschsprung disease, high anorectal malformations, [22] cystic fibrosis, chronic respiratory infections and cough, [23] lymphoid hyperplasia, rectal polyps, and shigellosis. [24] Rectal prolapse has been described in a case of Clostridium difficile –associated pseudomembranous colitis in a child. [25]

Broden and Snellman proposed a theory to explain the etiology of rectal prolapse. [26] They cineradiographically demonstrated that the entity implies a circumferential intussusception of the rectum, with its origin 3 inches above the anal margin.

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Epidemiology

In adults, rectal prolapse is 6 times more common in females than in males. Almost all patients have a history of constipation (75%), which stretches the pelvic floor and the anal sphincter mechanism, predisposing them to rectal prolapse.

In children, the incidence is higher during the first year of life, after which it becomes increasingly infrequent. It is slightly more common in boys than in girls. Whether prolapse in children is predominantly mucosal prolapse (procidentia) rather than full-thickness prolapse is controversial.

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Prognosis

Most cases reduce spontaneously. Otherwise, venous stasis, edema, and ulceration ensure. Longstanding or frequent recurrent prolapses lead to proctitis.

Approximately 10% of patients who experience rectal prolapse as children continue to be symptomatic into adulthood. Over 90% of children who experience rectal prolapse during the first 3 years of life respond to conservative treatment by age 6 years. Spontaneous resolution is much less likely in children who develop their first episode of prolapse after age 4 years.

After a surgical rectopexy, continence is achieved in 92% of patients. Resective procedures are associated with decreased recurrence rates. Recovery of continence after surgery is not immediate and may take as long as 12 months.

Nwako et al reported a 100% success rate with the Lockhart-Mummery procedure, which involves packing the presacral space with gauze through a posterior approach, with excision of the prolapsed mucosa. [27]

Hight et al recommend linear cauterization of the rectal mucosa, with a 98% success rate in 72 patients. [28]

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