What is the best treatment approach for a 19-month-old patient with chronic constipation?

Treatment of Chronic Constipation in a 19-Month-Old

Polyethylene glycol (PEG) is the first-line pharmacological treatment for chronic constipation in this 19-month-old child, dosed at 17 grams once daily mixed in 4-8 ounces of beverage, with the goal of achieving one non-forced bowel movement every 1-2 days without abdominal pain or straining. 1

Initial Assessment

Before starting treatment, you must:

• Perform a rectal examination to rule out fecal impaction, which requires disimpaction before maintenance therapy 2, 1
• Evaluate stool consistency and frequency of bowel movements to establish baseline 2
• Screen for secondary causes including medications or metabolic disorders 1
• Assess current dietary fiber and fluid intake 2, 1

Stepwise Treatment Algorithm

Step 1: Non-Pharmacological Measures (Start Immediately)

• Increase dietary fiber through fiber-rich foods as the foundation of treatment 2
• Target fiber intake of age + 5 grams per day minimum (approximately 24 grams daily for this child) 1
• Ensure adequate fluid intake, particularly important if the child is in the lowest quartile of daily consumption 1
• Establish regular toilet times, especially after meals, to utilize the gastrocolic reflex 2, 1
• Promote age-appropriate physical activity 2, 1

Step 2: First-Line Pharmacological Treatment

PEG is recommended as first-line maintenance therapy based on moderate-quality evidence in adults with supportive pediatric data 1:

• Dose: 17 grams once daily mixed in 4-8 ounces of beverage 1
• PEG increases complete spontaneous bowel movements effectively 2
• Common side effects include abdominal distension, loose stool, flatulence, and nausea 3

Fiber supplementation can be added if the child has adequate fluid intake 1:

• Psyllium has the best evidence among fiber supplements 2
• Start with low doses and increase gradually to minimize flatulence 2
• Glucomannan fiber supplementation has demonstrated benefit in pediatric constipation (45% success rate vs 13% with placebo) 4

Step 3: Second-Line Options (If No Response After 4 Weeks)

If constipation persists after 4 weeks of PEG therapy:

• Add bisacodyl as a stimulant laxative, 5-10 mg once daily 1
• Alternative osmotic agents include lactulose, magnesium hydroxide, or sorbitol 1
• Lactulose can be used if PEG is unavailable, though efficacy may vary 2

Step 4: Reassessment and Rescue Interventions

Reassess for underlying causes if treatment fails 1:

• Review medications that may cause constipation
• Evaluate for metabolic causes
• Consider pelvic floor dysfunction in persistent cases 5

Rescue interventions for impaction 1:

• Glycerin suppository
• Bisacodyl suppository
• Mineral oil retention enema

Treatment Goals and Monitoring

The primary goal is achieving at least 3 bowel movements per week without straining 2, or ideally one non-forced bowel movement every 1-2 days without abdominal pain 1.

Monitor and adjust treatment based on:

• Stool consistency and frequency 2
• Presence of abdominal pain or straining 1
• Soiling episodes 4

Critical Pitfalls to Avoid

• Do not use stool softeners alone - they are ineffective for chronic constipation 1
• Do not add supplemental fiber without ensuring adequate fluid intake - this can worsen constipation 1
• Do not limit PEG to 7 days in chronic constipation - response has been shown durable over 6 months in adults 3, 1
• Do not ignore the FDA warning to consult a physician if laxative use exceeds 1 week in the context of chronic constipation requiring ongoing management 6

Important Context

Most children with chronic constipation have functional constipation, often stemming from stool withholding patterns that may have started during toilet training 7. Approximately 70% of children have inadequate baseline fiber intake 4, 8, and even health-conscious families struggle to achieve recommended fiber intake without intensive dietary counseling 8. Children with constipation alone respond better to fiber therapy (69% success) compared to those with both constipation and encopresis (28% success) 4.

The recommendation for PEG is based on strong evidence in adults with moderate certainty 3, supported by pediatric data showing benefit when added to existing laxative therapy 4.