In an older adult with chronic constipation, what condition is characterized by stool exiting the anus and then being forced back into the rectum?

Rectal Prolapse (Full-Thickness External Rectal Prolapse)

The condition you're describing—where stool exits the anus and then is forced back into the rectum—is most likely rectal prolapse, specifically full-thickness (complete) external rectal prolapse, where the entire rectal wall protrudes through the anus and may become incarcerated. 1

What This Condition Is

Rectal prolapse occurs when the rectum (and sometimes sigmoid colon) protrudes circumferentially through the anal canal as a full-thickness intussusception. 1 This is most common in:

• Elderly patients (prevalence ~1% in adults over 65 years)
• Females (women:men ratio of 9:1)
• Those with chronic constipation and excessive straining 1

The prolapse can be:

• Intermittent: Comes out during defecation and spontaneously reduces
• Incarcerated: Cannot be manually reduced, becomes trapped outside
• Strangulated: Blood supply compromised, leading to ischemia, gangrene, or perforation 1

Immediate Assessment Required

Clinical Examination

Look for these specific features during physical exam:

• Concentric protrusion (not radial bulging like hemorrhoids)
• Edematous, painful rectal mass that cannot be reduced
• Signs of ischemia: dusky/dark tissue, ulceration, bleeding
• Signs of perforation: peritonitis, hemodynamic instability 1

Laboratory Tests

Order these specific tests:

• Complete blood count (leukocytosis suggests ischemia)
• Serum creatinine
• Inflammatory markers: C-reactive protein, procalcitonin, lactate (elevated lactate is a predictor of bowel necrosis and mortality) 1

Imaging

In hemodynamically stable patients: Obtain urgent contrast-enhanced CT scan of abdomen/pelvis to detect:

• Bowel obstruction
• Perforation/peritonitis
• Associated colorectal cancer (4.2-fold increased risk in rectal prolapse patients) 1

In hemodynamically unstable patients: Do NOT delay treatment for imaging—proceed directly to surgery 1

Treatment Algorithm

For Incarcerated Prolapse WITHOUT Ischemia or Perforation:

Attempt manual reduction first 1:

1. Place patient in Trendelenburg position
2. Administer IV sedation and analgesia
3. Apply topical granulated sugar or 50% dextrose to reduce edema (creates hyperosmolar environment)
4. Perform gentle manual reduction

Important caveat: Failure rate of conservative management is high, so do not delay surgery if reduction fails within 4-7 hours 1

For Strangulated Prolapse WITH Ischemia, Gangrene, Perforation, or Shock:

Immediate surgical intervention is mandatory 1

Surgical Approach Selection:

For hemodynamically unstable patients with peritonitis:

• Abdominal open approach (strong recommendation) 1

For hemodynamically stable patients:

• Laparoscopic rectopexy is preferred (lower recurrence rate 0-8%, fewer complications, shorter hospital stay) 2, 3
• Perineal approach (Altemeier procedure) reserved for:
  • Elderly patients
  • Significant medical comorbidities
  • Contraindications to abdominal surgery
  • Note: Higher recurrence rate (5-21%) but lower perioperative morbidity 2, 1

Avoid bowel resection in patients with pre-existing diarrhea or incontinence, as these symptoms worsen with resection 2

Antibiotic Coverage:

In strangulated prolapse, administer empiric broad-spectrum antibiotics due to risk of bacterial translocation 1

Critical Pitfalls to Avoid

1. Do not confuse with hemorrhoids: Rectal prolapse is concentric; hemorrhoids are radial discrete cushions 1
2. Do not delay surgery for prolonged conservative attempts—ischemia and perforation can develop rapidly 1
3. Screen for colorectal cancer: All patients with rectal prolapse should undergo colonoscopy/flexible sigmoidoscopy given the 4.2-fold increased cancer risk 1
4. Address underlying constipation: Chronic straining is the root cause; postoperative management must include bowel regimen to prevent recurrence 1, 4