What is the initial treatment for a 3-year-old child presenting to the Emergency Room (ER) with moderate constipation?

Emergency Room Treatment for Moderate Constipation in a 3-Year-Old

For a 3-year-old presenting to the ER with moderate constipation, initiate oral polyethylene glycol (PEG) as first-line therapy after ruling out fecal impaction and bowel obstruction through physical examination.

Initial Assessment

Before initiating treatment, perform a focused physical examination to identify critical conditions:

• Rule out fecal impaction through abdominal and rectal examination, particularly if the child has paradoxical diarrhea (overflow incontinence around impaction) 1
• Rule out bowel obstruction through physical exam; abdominal radiographs are generally not useful for differentiating functional from organic constipation and should be avoided 2
• Assess for red flag symptoms suggesting organic causes (though these are rare, accounting for only 5% of cases): delayed passage of meconium beyond 48 hours, failure to thrive, or neurological abnormalities 3, 4

Treatment Protocol for Moderate Constipation WITHOUT Impaction

Primary therapy:

• Polyethylene glycol (PEG) is the first-line treatment for children over 6 months of age 5, 4
• Administer PEG powder mixed with water or juice in the ER and provide discharge prescription 3, 2

Alternative options if PEG unavailable:

• Lactulose 2.5-10 mL divided doses for infants, or 40-90 mL total daily dose for older children and adolescents 6, 5
• Magnesium hydroxide (milk of magnesia) 30-60 mL daily to twice daily 1, 3
• Mineral oil as an alternative maintenance option 3, 4

Treatment Protocol for Moderate Constipation WITH Impaction

If impaction is confirmed on physical examination, disimpaction must occur before maintenance therapy:

Disimpaction options:

• High-dose oral PEG for the first few days is preferred and well-tolerated 5, 4
• Glycerine suppository as a gentler rectal option 1
• Fleet enema (phosphate enema) if oral therapy fails, though nearly half of constipated children in one ED study received enemas when less invasive options may have sufficed 7

Critical Pitfalls to Avoid

• Do not obtain abdominal radiographs routinely—they do not differentiate functional from organic causes and lead to unnecessary radiation exposure 7, 2
• Do not use stimulant laxatives (bisacodyl, senna) as first-line therapy in the acute ER setting; these are reserved for persistent constipation despite osmotic laxatives 1, 2
• Do not discharge without maintenance therapy—one study found only 25% of children received longer-term management plans, contributing to return ED visits 7
• Do not recommend fiber supplementation acutely—while dietary fiber may help long-term, medicinal fiber like psyllium is ineffective for acute constipation 1

Discharge Planning

Provide specific maintenance instructions:

• Continue PEG or lactulose daily for months, as functional constipation commonly relapses (40-50% experience relapse within 5 years) 2
• Educate families that treatment duration is typically prolonged—months to years—to prevent recurrence 5, 4
• Encourage adequate fluid intake and age-appropriate diet 1
• Consider trial of withholding cow's milk, as it may promote constipation in some children 3

Follow-up:

• Arrange primary care follow-up within 1-2 weeks to monitor response and adjust dosing 2
• Goal is 1 non-forced bowel movement every 1-2 days 1