Vitamin A Deficiency

Functional constipation is infrequent, difficult or painful defaecation without an identifiable organic cause and accounts for the great majority of childhood constipation. Stool withholding after a painful bowel movement creates a cycle of progressive rectal distension, larger stools, further pain and eventually overflow soiling.

Red flags suggest Hirschsprung disease, spinal pathology, endocrine disease, coeliac disease or another organic cause.

• Fewer than three stools per week
• Large, hard stools
• Painful defaecation
• Stool withholding behaviour
• Abdominal pain
• Palpable faecal mass
• Overflow faecal soiling
• Anal fissure

Red flags include delayed passage of meconium beyond 48 hours, constipation from the first weeks of life, severe abdominal distension, bilious vomiting, poor growth, abnormal lower limb neurology or abnormal anal anatomy.

Diagnosis is clinical.

Routine abdominal radiography is unnecessary.

Investigate for an organic cause only when red flags are present, symptoms are refractory, or growth and examination are abnormal.

Rectal examination is not required routinely and should be reserved for situations where it will genuinely change diagnosis or management.

• Assess first for faecal impaction.

• Polyethylene glycol with electrolytes is first line for disimpaction, using an escalating oral regimen. Add a stimulant laxative if disimpaction is unsuccessful after an adequate trial.

• After disimpaction, continue polyethylene glycol as maintenance treatment and titrate to produce regular soft stools. Treatment commonly continues for months, not days, and should not be stopped abruptly.

• If polyethylene glycol is unavailable or poorly tolerated, lactulose 1 to 3 mL/kg/day PO in divided doses can be used, adjusted to stool response.

• Combine medication with regular toilet sitting after meals, positive reinforcement, adequate dietary fibre and normal fluid intake.

• Diet alone is insufficient treatment for established functional constipation.