What is the appropriate treatment for constipation in a 2.5‑month‑old infant who has had no stool for seven days?

Treatment of Constipation in a 2.5-Month-Old Infant with 7 Days Without Stool

For a 2.5-month-old infant with 7 days of constipation, start with fruit juices containing sorbitol (prune, pear, or apple juice) at 10 mL/kg body weight, and if this fails after a few days, advance to glycerin suppositories for immediate relief, followed by lactulose if needed for maintenance. 1, 2

Immediate Assessment Before Treatment

Before initiating therapy, evaluate for red-flag symptoms that require urgent referral:

• Check for bilious vomiting, which indicates potential obstruction and requires immediate evaluation 1
• Assess for significant abdominal distension, which warrants prompt medical assessment 1
• Look for signs of dehydration (dry mucous membranes, reduced skin turgor) requiring urgent evaluation 1
• Evaluate for excessive irritability with back arching, an alarm feature necessitating immediate clinical review 1
• Verify adequate weight gain—inadequate weight gain or weight loss is a red-flag sign for possible pathology 1

Perform a visual inspection of the perianal area for fissures, skin tags, or redness 1. Digital rectal examination is typically not necessary for functional constipation in infants and should be reserved for cases with red flags 1.

First-Line Treatment: Sorbitol-Containing Fruit Juices

The North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition specifically recommends fruit juices containing sorbitol as first-line treatment for infants under 1 year 1:

• Administer prune, pear, or apple juice at 10 mL/kg body weight (approximately 85 mL for an 8.5 kg infant) 1
• These juices work through their poorly absorbed sorbitol and carbohydrate content, creating an osmotic load that increases stool water content and frequency 1
• Avoid excessive juice consumption as it may lead to diarrhea, flatulence, abdominal pain, and poor weight gain 1

Second-Line Treatment: Glycerin Suppositories

If fruit juices fail after 2-3 days:

• Glycerin suppositories are the recommended first-line suppository option for infants, acting as a rectal stimulant through mild irritant action and are safe for this age group 2
• They provide immediate relief for fecal impaction if present 2

Third-Line Treatment: Lactulose

If suppositories provide only temporary relief:

• Lactulose is recommended as maintenance therapy after initial relief with suppositories 1
• For an 8.5 kg infant, the dose translates to approximately 8-17 mL of lactulose syrup (10 g/15 mL solution) per day, titrated to produce soft, painless stools 2
• Avoid liquid lactulose preparations containing sorbitol in very young infants, as the hyperosmolar preservative can lead to complications 2

Feeding Optimization and Supportive Measures

Simultaneously implement these measures:

• Increase feeding frequency to 8-10 sessions per 24 hours, which is associated with higher stool frequency 1
• Continue breastfeeding on demand or use full-strength formula—do not dilute formula as it does not help constipation and may compromise nutrition 1
• Implement regular burping during feeds to minimize gastric distension 1
• Maintain the infant upright for 10-20 minutes after each feeding to aid gastrointestinal transit 1
• Gentle clockwise abdominal massage can help stimulate bowel movements 1
• Provide a warm bath to promote relaxation and improve gastrointestinal motility 1

Consider Cow's Milk Protein Intolerance

If constipation persists despite the above measures:

• Milk-protein allergy can manifest as constipation in formula-fed infants, mimicking functional constipation 1
• Implement a 2-4 week trial of an extensively hydrolyzed protein formula or amino-acid-based formula to identify cow's milk protein intolerance 1
• A 2013 pediatric study found that 24% of formula-fed infants with gastrointestinal symptoms (including constipation) resolved after switching to a protein-hydrolysate formula 1

Critical Practices to Avoid

• Do not use bisacodyl in infants under 6 months—there is no safety or efficacy data for this age group, and safer alternatives exist 2
• Avoid routine rectal stimulation as it can lead to dependence and mucosal trauma 1
• Do not dilute infant formula—this does not alleviate constipation and compromises nutritional adequacy 1
• Avoid introducing multiple changes simultaneously—modify one variable at a time to identify what works 1

When to Refer

• Persistent symptoms despite appropriate conservative management for 4-8 weeks warrant referral to pediatric gastroenterology 1
• Presence of systemic illness signs (fever, lethargy) should prompt specialist evaluation 1
• Ongoing inadequate weight gain or weight loss despite dietary adjustments is an indication for specialist assessment 1
• Delayed passage of first stool beyond 48 hours after birth (if this history is present) is a red-flag for Hirschsprung disease requiring surgical evaluation 2

Parent Education

• Instruct parents to monitor for warning signs (vomiting, worsening distension, blood in stool, fever) and return if symptoms worsen 1
• Educate about normal bowel patterns—by 2 months, feeding patterns change to every 3-4 hours, which can affect stool frequency 1
• Emphasize that treatment may need to continue for several weeks before normal bowel patterns are re-established 2