Rectal prolapse

Rectal prolapse is the protrusion of rectal mucosa (mucosal prolapse) or the entire rectum (full-thickness prolapse) through the anal opening. While mucosal prolapse is more common in children, full-thickness prolapse occurs more commonly in adults. Increased intra-abdominal pressure (e.g., excessive straining as a result of constipation) and weakness of the pelvic floor muscles (e.g., as a result of old age, multiple pregnancies) are risk factors for rectal prolapse. Cystic fibrosis, moreover, is an important risk factor in children. The most commonly presenting complaint is a painless rectal mass that appears on straining. Other symptoms include fecal incontinence and/or constipation and pruritus ani. Inspection of the prolapsed structure helps to determine the type: In partial prolapse, radial folds are typically present in the mucosa, while a complete prolapse exhibits concentric mucosal folds. If clinical examination does not reveal any significant findings, video defecography may be used to confirm the diagnosis. Mucosal prolapse can be treated conservatively with digital reduction or injection sclerotherapy. Full-thickness prolapse, on the other hand, usually requires surgery. Surgery for full-thickness prolapse may be conducted either using an abdominal or a perineal approach, usually determined on a case-by-case basis.

• Age of onset: bimodal incidence
  • Adults
    • ♂: < 40 years
    • ♀: 60–70 years
  • Children: < 3 years
• Sex
  • Adults: ♀ > ♂ (6:1)
  • Children: ♀ = ♂

References:^[1][2]

Epidemiological data refers to the US, unless otherwise specified.

• Risk factors in adults
  • Any cause of raised intraabdominal pressure
    • Chronic straining as a result of constipation and/or benign prostatic hypertrophy (BPH)
    • Chronic cough (e.g. COPD)
    • Pregnancy
  • Weakness of the pelvic floor muscles
    • Advanced age
    • Multiparous women
    • Damage to the pudendal nerve or sacral roots (e.g., obstetric injury during vaginal delivery, diabetic neuropathy, pelvic tumors)
    • Previous perineal surgery (e.g., for the management of anal fistulas)
    • Connective tissue disorders (e.g., Ehler Danlos syndrome)
• Risk factors in children
  • Chronic straining as a result of constipation
  • Recurrent diarrhea
  • Cystic fibrosis
  • Rectal parasites (e.g., whipworm)
  • High anorectal malformations
  • Hirschsprung disease
  • Damage to the sacral roots (e.g., meningomyelocele)
  • Significant weight loss

References:^[1][2][3][4]

Depending on the severity of the rectal prolapse, rectal prolapse may be classified as:

• Mucosal prolapse (partial prolapse)
  • Protrusion of the rectal mucosa through the anus
  • Typically less than 4 cm in length
  • Much more common in children and infants
• Full-thickness prolapse (complete prolapse)
  • Usually begins as a rectal intussusception; therefore, all layers of the rectal wall protrude through the anus.
  • > 4 cm in length (usually 10–15 cm long when fully prolapsed)
  • Much more common in adults

Referenes:^[1][2]

Symptoms

• A painless rectal mass that protrudes through the anus
• Fecal incontinence
• Constipation
• Pruritus ani
• Rectal bleeding

Physical examination

The perineum should ideally be examined while the patient squats or strains.

• The rectum protrudes partially or completely through the external anal opening.
  • Mucous prolapse
    • Radial mucosal folds are seen on inspection
    • Only a double layered mucous membrane can be palpated.
  • Full-thickness prolapse
    • Concentric mucosal folds are seen on inspection (stacked-coin appearance)
    • All four layers of the rectal wall can be palpated.
    • A sulcus or groove may be present between the emerging mass and the walls of the anal canal.
• A solitary rectal ulcer on the prolapsed rectum is seen in 10–25% of cases.
• Digital rectal examination may reveal anal sphincter weakness and a mass or other pelvic floor pathology.
• Other conditions associated with pelvic floor weakness (e.g., uterine prolapse, vaginal vault prolapse, cystocele, rectocele) may be present along with rectal prolapse.

References:^[1][2][5]

• Definitive diagnosis
  • Rectal prolapse is primarily a clinical diagnosis.
  • Video defecography: to distinguish full-thickness rectal prolapse from mucosal prolapse when the diagnosis is not obvious from clinical examination alone
• Additional tests
  • Proctoscopy and/or colonoscopy should be performed prior to any surgical therapy.
  • If a rectal ulcer is present: biopsy of the rectal ulcer
  • If fecal incontinence is present: anal sphincter manometry
  • If pelvic floor weakness is suspected: dynamic pelvic floor MRI
  • A sweat chloride test should be performed among children with rectal prolapse to rule out cystic fibrosis.

References:^[2][3][6]

Mucosal prolapse

• Mucosal prolapse is generally managed nonsurgically.
  • First-line: reduction of mucosal edema, digital repositioning of the rectum, and pressure padding the perineum
  • Second-line: injection sclerotherapy
• Grade III and grade IV internal hemorrhoids that are often associated with a mucosal prolapse should be treated with hemorrhoidectomy (see “Treatment” in hemorrhoids)

Full-thickness rectal prolapse

Full-thickness prolapse requires surgical treatment with either an abdominal or perineal approach.

• Abdominal procedures: laparoscopic rectopexy with/without sigmoidectomy
• Perineal procedures
  • Short, full-thickness prolapse: Delorme procedure
  • Long, full-thickness prolapse that cannot be treated by abdominal procedures: Altemeier procedure (perineal rectosigmoidectomy)

While surgery is performed electively in most cases, incarcerated rectal prolapse should be treated as a surgical emergency!

In addition to definitive management of rectal prolapse, any underlying risk factors (e.g., constipation) must be addressed in order to prevent recurrence.
References:^[1][5][7]