Constipation in Children

Overview

Constipation describes defecation that is unsatisfactory due to infrequent stools, difficulty passing stools, or the sensation of incomplete emptying. It may be functional (idiopathic) or secondary to an underlying disorder.

Epidemiology

• Functional (idiopathic) constipation accounts for >95% of cases of constipation in children
• Constipation is most commonly seen in infants when weaning, toddlers learning to use the toilet or school age

Causes

• Most cases are idiopathic
• Low-fibre diet
• Dehydration
• Drugs (e.g. opiates)
• Anal fissure
• Rectal prolapse
• Hirschsprung’s disease
• Cerebral palsy
• Spina bifida
• Learning disability
• Abuse

Presentation

Overview

Children may present with painful defecation and/or a reduced frequency in passing stools. This can lead to excessive water reabsorption in the colon which causes hardening of the stool. This can then lead to:

• Pain when passing stools and sphincter contraction to avoid discomfort (withholding behaviour)
• Further reabsorption of water, more hardening of the stool, and an increase in its size
• More withholding behaviours and further increases in stool hardness and size
• Eventually, overflow incontinence follows where softer stool passes around the retained harder stool

NICE has produced criteria that diagnose constipation, and then further criteria to confirm that it is idiopathic and refute underlying causes. These are discussed below.

Diagnosing constipation

For a child <1 year old, any two of the following constitutes a diagnosis of constipation:

• Stool pattern:
  • <3 complete stools per week (type 3 or 4 on the Bristol Stool Form Scale) except for exclusively breastfed babies after 6 weeks of age
  • Hard, large stools
  • ‘Rabbit droppings’ (type 1 on the Bristol Stool Form Scale)
• Symptoms associated with defecation:
  • Distress on stooling
  • Bleeding with hard stool
  • Straining
• History:
  • Previous episode(s) of constipation
  • Previous or current anal fissure

For a child >1 year old, any two of the following constitutes a diagnosis of constipation:

• Stool pattern:
  • <3 complete stools per week (type 3 or 4 on the Bristol Stool Form Scale)
  • Overflow soiling (very loose, very smelly, stool passed without sensation)
  • ‘Rabbit droppings’ (type 1 on the Bristol Stool Form Scale)
  • Large, infrequent stools that can block the toilet
• Symptoms associated with defecation:
  • Poor appetite that improves with passage of large stool
  • Waxing and waning abdominal pain with passage of stool
  • Retentive posturing: straight-legged, tiptoed, back arching posture
  • Straining
  • Anal pain
• History:
  • Previous episode(s) of constipation
  • Previous or current anal fissure
  • Painful bowel movements and bleeding associated with hard stools

Excluding secondary causes

If no red or amber flags are present, then a diagnosis of idiopathic constipation can be made:

• Timing:
  • Features suggesting idiopathic constipation:
    • Starts after a few weeks of life
    • Obvious precipitating factor coinciding with the start of symptoms (e.g. fissure, diet changes, infection, moving house, starting nursery/school, fears and phobias, major environment changes, major family changes, taking medicine)
  • Red-flag features suggesting an underlying disorder:
    • Reported from birth or the first few weeks of life
• Passage of meconium:
  • Features suggesting idiopathic constipation:
    • <48 hours 
  • Red-flag features suggesting an underlying disorder:
    • >48 hours
• Stool patterns:
  • Features suggesting idiopathic constipation:
    • n/a
  • Red-flag features suggesting an underlying disorder:
    • ‘Ribbon’ stools
• Growth:
  • Features suggesting idiopathic constipation:
    • Generally well, weight and height within normal limits, fit and active 
  • Red-flag features suggesting an underlying disorder:
    • Faltering growth – an ‘amber flag’
• Neuro/locomotor:
  • Features suggesting idiopathic constipation:
    • No neurological problems in legs
    • Normal locomotor development 
  • Red-flag features suggesting an underlying disorder:
    • Previously unknown or undiagnosed weakness in legs
    • Locomotor delay
• Abdomen:
  • Features suggesting idiopathic constipation:
    • n/a
  • Red-flag features suggesting an underlying disorder:
    • Distention
• Diet:
  • Features suggesting idiopathic constipation:
    • Changes in diet (e.g. infant formula, weaning)
    • Insufficient fluid intake
    • Poor diet
  • Red-flag features suggesting an underlying disorder:
    • n/a
• Other:
  • Features suggesting idiopathic constipation:
    • n/a
  • Red-flag features suggesting an underlying disorder:
    • Disclosure or evidence that raises concerns over the possibility of child maltreatment

Management

Faecal impaction

Assess the child for faecal impaction as this can change management steps, particularly the dosages and timings of different treatments. Features suggesting faecal impaction are:

• Severe constipation
• Overflow soiling
• Faecal masses palpable in the abdomen
• A digital rectal examination should only be performed by a specialist

Overview

Both disimpaction and maintenance therapy follow similar steps:

• 1^st-line: Movicol (polyethylene glycol 3350 + electrolytes) 
• If no disimpaction after 2 weeks: add stimulant laxative (e.g. senna, bisacodyl, docusate)
• If Movicol is not tolerated: use stimulant laxative monotherapy or combine with an osmotic laxative (e.g. lactulose)
• Inform parents that soiling and abdominal pain may initially worsen

Other points:

• Do not use lifestyle and dietary changes alone to treat idiopathic constipation but ensure that the child has enough fibre and fluid intake