Full Thickness Rectal Prolapse Definition
Full thickness rectal prolapse is a circumferential, complete protrusion of the entire rectal wall (all layers) through the anus, also known as true or Type III rectal prolapse. 1
Anatomic Definition
- Full thickness rectal prolapse involves intussusception and protrusion of the rectum with its entire wall—including mucosa, submucosa, and muscularis propria—through the anal canal 1, 2
- This distinguishes it from partial (mucosal) prolapse, which involves only the mucosal and submucosal layers 3
- The prolapse may include the sigmoid colon in addition to the rectum in some cases 1
Clinical Presentation Features
- The prolapse appears as a concentric, circumferential protrusion on examination, which differentiates it from prolapsed hemorrhoids that show radial bulging of discrete anal cushions 1
- The prolapse may be intermittent (reducible) or incarcerated (cannot be reduced manually), presenting as a large, painful, immobile rectal mass 1
- When incarcerated, the prolapse can progress to strangulation with compromised blood supply, leading to necrosis and perforation—a life-threatening emergency 1
Epidemiology in Older Adults
- Full thickness rectal prolapse has an incidence of approximately 2.5 per 100,000 inhabitants with a prevalence of 1% in adults over 65 years 1, 4
- The condition shows a striking female predominance with a women:men ratio of 9:1 1, 4
- It occurs at extremes of life but is most commonly seen in elderly females 1
Pathophysiology in High-Risk Populations
- Chronic straining during defecation and chronic increases in intra-abdominal pressure weaken pelvic floor support structures over time 4
- Direct or denervation injury to pelvic floor musculature increases stress on the fascia, leading to progressive weakening 4, 5
- In older women, menopause, vaginal multiparity, and chronic straining contribute to mechanical stretching and failure of the rectovaginal septum, levator ani muscles, and endopelvic fascia 5
Associated Complications
- Fecal incontinence is the predominant symptom, resulting from mechanical stretching and damage to anal sphincters as the prolapsed rectum repeatedly passes through the anal canal 4, 5
- Concurrent pelvic organ prolapse is common, including cystocele, enterocele, uterovaginal prolapse, and bladder prolapse, reflecting global pelvic floor failure 5
- Critical pitfall: Colorectal cancer screening is mandatory, as rectosigmoid cancer prevalence is 5.7% in patients with rectal prolapse compared to 1.4% in age-matched controls (4.2-fold increased relative risk) 5
Diagnostic Approach
- Diagnosis is primarily clinical, based on patient history, symptoms, and physical examination 1
- Visualization may require the patient to strain while sitting or squatting to demonstrate the prolapse 3, 6
- Laboratory tests (complete blood count, serum creatinine, inflammatory markers like CRP, procalcitonin, and lactate) should be obtained when complicated prolapse with incarceration or strangulation is suspected 1
- Dynamic imaging (cystocolpoproctography or MR defecography) can confirm diagnosis when uncertain and detect concurrent pelvic floor abnormalities 1, 5
- Contrast-enhanced CT of abdomen and pelvis is indicated in complicated cases to detect bowel obstruction, perforation, or colorectal malignancy 5