Description

There are three types of rectal prolapse:

• Complete: full thickness of rectum prolapses through anus (two layers of rectum with an intervening peritoneal sac, which may contain small bowel)
• Incomplete/mucosal: prolapse limited to only two layers of mucosa
• Concealed: internal intussusception of upper rectum into lower, with no extrusion into the anus

Epidemiology

• Most cases occur in children <4 years of age around time of toilet training; equal incidence in boys and girls
• In older children and adults, strong (6-fold) female predilection
• Common in developing countries, perhaps because of poor nutrition and parasitic infection; less common in industrialized countries

Risk Factors

• Cystic fibrosis (CF)
  • Typically presents between 6 months and 3 years of age in patients with CF
  • Presentation in children with CF >5 years of age is rare.
• Chronic constipation
  • About 50% of children with chronic constipation will experience prolapse.

Etiology

Exact etiology uncertain

Commonly Associated Conditions

• Excessive straining with bowel movements from constipation and toilet training (hips and knees flexed) is the most common cause in industrialized countries.
• Diarrhea; may be more of a cause in tropical and subtropical countries
• Infections: hookworms and other parasitic infections
• Malnutrition; can cause loss of the ischiorectal fat pad
• Complication of past surgery, such as imperforate anus repair
• Complete prolapse is rare in children, but when it occurs, it may be related to poor fixation of rectum to sacrum and to weak pelvic and anal musculature.
• CF
• Ulcerative colitis
• Hirschsprung disease
• Ehlers-Danlos syndrome
• Meningomyelocele
• Pertussis
• Rectal polyp
• Pneumonia
• Anorexia
• Rectal neoplasm