What are the next steps for managing ongoing stool impaction and constipation after peri-rectal abscess drainage in a patient already using daily senna and Polyethylene Glycol (PEG)?

Management of Ongoing Stool Impaction and Constipation After Peri-rectal Abscess Drainage

For patients with ongoing stool impaction and constipation after peri-rectal abscess drainage who are not responding to daily senna and polyethylene glycol (PEG), escalate treatment with high-dose PEG (up to 8 sachets/1L per day for 2-3 days) combined with suppositories or enemas for disimpaction, followed by a maintenance bowel regimen.

Assessment of Current Situation

Before escalating therapy, perform:

• Digital rectal examination to assess for persistent fecal impaction
• Abdominal examination to evaluate extent of fecal loading
• Review of medication list to identify and discontinue constipating medications

Treatment Algorithm for Refractory Constipation/Impaction

Step 1: Disimpaction Phase

• For confirmed fecal impaction:

  • High-dose PEG: Increase to 8 sachets (17g each) daily divided in 2-4 doses (maximum 1L/day) for 2-3 days 1
  • Add bisacodyl or glycerol suppositories 30 minutes after meals to synergize with the gastrocolonic response 2
  • Consider mineral oil enemas if not contraindicated 2

• Contraindications for enemas 2, 3:

  • Neutropenia or thrombocytopenia
  • Paralytic ileus or intestinal obstruction
  • Recent colorectal or gynecological surgery
  • Recent anal or rectal trauma
  • Severe colitis, inflammation or infection
  • Undiagnosed abdominal pain
  • Recent pelvic radiotherapy

Step 2: Maintenance Phase (After Successful Disimpaction)

• Continue PEG 17g daily with senna (2-3 tablets daily) 4
• Add stimulant laxative if needed (bisacodyl 10-15mg daily) 2
• Consider adding docusate sodium as a stool softener 5

Step 3: For Refractory Cases

• If no response to above measures, consider adding lubiprostone 24mcg twice daily with food 6
• Refer for biofeedback therapy if defecatory disorder is suspected 2

Non-Pharmacological Interventions

• Ensure adequate fluid intake (at least 2L daily unless contraindicated) 3
• Optimize toileting schedule: attempt defecation at least twice daily, 30 minutes after meals 2, 3
• Consider abdominal massage to improve bowel efficiency 2
• Ensure privacy and comfort during defecation 2
• Use proper positioning (small footstool may help exert pressure more easily) 2
• Increase physical activity within patient limits 2, 3

Monitoring and Follow-up

• Aim for one non-forced bowel movement every 1-2 days 3
• Monitor for adverse effects of high-dose PEG (abdominal pain, bloating)
• If symptoms persist despite treatment, consider:
  • Colonic transit study
  • Referral to gastroenterology for specialized testing (anorectal manometry, defecography)

Special Considerations for Post-Abscess Patients

• Assess for perianal pain that may be contributing to constipation through voluntary withholding
• Ensure adequate pain management during bowel movements
• Monitor for recurrence of perianal abscess or development of fistula

High-dose PEG has shown excellent response rates (89.3%) for severe constipation and fecal impaction 1, making it the preferred initial approach for escalation therapy. The combination of PEG with senna has demonstrated good efficacy with fewer side effects than high-volume PEG alone 4.