What are the treatment options for constipation and soiling?

Pathophysiology of Constipation and Soiling: Explanation and Treatment Options

Pathophysiology Explanation for Patients

Constipation and soiling occur when normal bowel movement patterns are disrupted, leading to infrequent, difficult bowel movements and involuntary stool leakage around impacted feces. 1

The process can be explained as follows:

• Normal bowel function: The colon absorbs water from stool, and regular contractions (peristalsis) move stool toward the rectum. When stool reaches the rectum, it triggers the urge to defecate.

• Constipation development:

  • When stool moves too slowly through the colon, excessive water absorption occurs
  • Stool becomes hard, dry, and difficult to pass
  • Over time, the rectum stretches to accommodate accumulated stool
  • Stretched rectal walls become less sensitive to the presence of stool
  • The urge to defecate diminishes or disappears

• Soiling mechanism:

  • Liquid stool from higher in the colon flows around the impacted hard stool
  • This liquid stool leaks out involuntarily (soiling/encopresis)
  • The child often doesn't feel this happening due to decreased rectal sensitivity

Treatment Options

First-Line Treatment: Polyethylene Glycol (PEG)

Polyethylene glycol (PEG) is the recommended first-line treatment for constipation due to its proven efficacy, safety profile, and low cost. 1

• Dosing: 17g daily mixed in 8oz water
• Mechanism: Increases water content in the colon, softening stool
• Benefits: Effectively increases complete spontaneous bowel movements
• For children: Age-appropriate dosing under medical supervision

Dietary Interventions

• Fiber intake: Increase to age + 5g per day for children; approximately 30g/day for adults 1

  • Soluble fiber (psyllium) is more effective than insoluble fiber for constipation 2, 3
  • Psyllium is superior to docusate sodium for stool softening 4

• Fluid intake: Adequate hydration, particularly water

• Helpful foods: Prune, pear, and apple juices (contain sorbitol that helps increase stool frequency) 1

• Foods to avoid: Lactose-containing products, alcohol, high-osmolar supplements 1

Other Medication Options

1. FDA-approved medications for chronic constipation:

   • Linaclotide: Strongly recommended for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation in adults, and functional constipation in children 6-17 years 1, 5
   • Lubiprostone: Conditionally recommended for chronic idiopathic constipation, opioid-induced constipation, and IBS-C in women 1, 6

2. Other laxative options:

   • Lactulose: Conditionally recommended osmotic laxative 1
   • Stimulants: Senna, bisacodyl, sodium picosulfate 1
   • Bulk-forming: Methylcellulose (less gas-producing than psyllium) 1
   • For opioid-induced constipation: Methylnaltrexone 0.15mg/kg subcutaneously for refractory cases 1

Behavioral Interventions

• Biofeedback therapy: Improves symptoms in >70% of patients with defecatory disorders 1

• Toileting habits:

  • Attempt defecation 30 minutes after meals (utilizing gastrocolic reflex)
  • Optimize toileting position (use footstool)
  • Ensure regular toilet access, especially for patients with decreased mobility

• Physical activity: Regular moderate exercise as tolerated 1

• Abdominal massage: Particularly helpful for patients with neurogenic problems 1

Treatment Algorithm

1. Initial approach:

   • Start PEG (17g daily in 8oz water)
   • Increase dietary fiber (preferably soluble fiber like psyllium)
   • Ensure adequate fluid intake
   • Implement behavioral interventions

2. If inadequate response:

   • Increase PEG dose or frequency
   • Add a stimulant laxative (senna or bisacodyl)

3. For refractory cases:

   • Consider prescription medications (linaclotide, lubiprostone)
   • Evaluate for defecatory disorders and consider biofeedback
   • For opioid-induced constipation, consider methylnaltrexone

Special Considerations

• Elderly patients: Require particular attention to assessment and toilet access 1

• Opioid-induced constipation:

  • Prophylactic PEG is recommended
  • Avoid bulk-forming laxatives (ineffective for opioid-induced constipation)
  • Adjust laxative dosing when increasing opioid doses 1

• Cautions:

  • Liquid paraffin should be avoided for bed-bound patients (aspiration risk)
  • Use saline laxatives cautiously in renal impairment
  • Enemas are contraindicated in neutropenia, thrombocytopenia, and after recent colorectal surgery 1