Aetiology

Multiple factors act as predisposing factors for rectal prolapse.

Infants and children

• anatomical/structural abnormalities
  • absent Houston valves (seen in 75% of prolapse in children <1 year)
  • anorectal hypotonia
  • low position of the rectum
  • megacolon (Hirschsprung disease)
  • poor underlying tissue support for anal mucosa
  • redundant sigmoid colon
  • underdeveloped sacral curve leading to direct downward course of the rectum
• functional causes
  • chronic straining associated with constipation
  • infectious disease
  • chronic diarrhoea
  • parasitic infestations (trichuriasis)
• other
  • cystic fibrosis
  • malnutrition
  • neoplasm (polyps)
  • neurologic disorders (meningomyelocele)

Adults

• anatomical/structural abnormalities
  • lack of or poor attachment of the rectum to the retrorectal tissues and sacrum
  • pelvic floor muscle weakness
  • prior pelvic surgery
• neurologic disorders
  • cerebrovascular accident
  • dementia
  • pudendal neuropathy
• other
  • multiparity
  • psychiatric disorders

Reference:

1. American Academy of Family physicians (AAFP). FP Comprehensive 2016 - Board Preparation. Anorectal conditions. Rectal prolapse