Most Common Cause of Rectal Prolapse
Chronic straining during defecation and conditions causing chronic increases in intra-abdominal pressure are the primary causes of rectal prolapse, leading to weakening of pelvic floor support structures. 1
Pathophysiology and Risk Factors
The development of rectal prolapse stems from deficient pelvic floor support, which occurs through multiple mechanisms:
Chronic straining is the fundamental causative factor, particularly in patients with constipation or defecatory disorders, as it progressively weakens the pelvic floor musculature and fascial support structures 2
Direct or denervation injury to the pelvic floor musculature increases stress on the fascia and leads to progressive weakening of pelvic floor support 1
Key risk factors include: advanced age, menopause, vaginal multiparity, obesity, chronic straining, and any conditions resulting in chronic increases in intra-abdominal pressures 1
Clinical Context
The relationship between straining and prolapse is well-established across the spectrum of pelvic floor disorders:
Solitary rectal ulcer, internal rectal intussusception, and complete rectal prolapse represent a continuum of defecatory disorders that share chronic straining as a common etiology 2
When the pelvic floor is weakened by chronic straining, external prolapse is frequently complicated by fecal incontinence due to mechanical stretching and damage of the anal sphincters over time 3, 2
The progression from internal intussusception to complete external prolapse reflects the cumulative effect of repetitive straining on already compromised pelvic floor support 4
Important Clinical Pitfalls
Avoid attributing rectal prolapse solely to constipation without recognizing the broader context of chronic straining. While constipation is common, the actual mechanism is the repetitive straining behavior, which can occur with various defecatory disorders including paradoxical pelvic floor contraction (dyssynergia) 1. Patients may even have daily bowel movements yet still experience chronic straining 1.