Constipation in children

For adults, see the separate Constipation in Adults article.

Constipation in children

Constipation in children is a common problem affecting between 5% and 30% of children¹ . It is often accompanied by parental anxiety. It is typically characterised by infrequent bowel evacuations, large stools and difficult or painful evacuation. About a third of patients develop chronic symptoms, and referral to secondary care is common. Constipation accounts for 3-5% of all paediatric referrals and 10-25% of all paediatric gastroenterology referrals² .

Clinicians should take care when dealing with requests for laxatives for a child. It is recommended that the child be seen for a proper assessment and diagnosis.

Definitions of constipation

Constipation is a heterogeneous, symptom-based disorder which describes defecation that is unsatisfactory because of infrequent stools, difficulty passing stools, or the sensation of incomplete emptying. It is most important to distinguish the normal from the abnormal.

• Functional (idiopathic) constipation as defined by the Rome IV criteria³ - (at least two of the following in infants up to 4 years old):

  • Fewer than two bowel movements per week.

  • A history of excessive stool retention.

  • A history of painful, or hard bowel movements.

  • Passing large-diameter stools (eg, they block the toilet).

  • Presence of a large faecal mass in the rectum.

• In toilet-trained children the following additional criteria can be used:

  • At least one episode per week of incontinence.

• Chronic constipation - two or more of the following in the preceding eight weeks:
  

  • Fewer than three bowel movements per week.

  • More than one episode of faecal incontinence per week.

  • Either palpable stools in the abdomen, or large stools palpable rectally.

  • Passing stools so large they block the toilet.

  • Retentive posturing and withholding behaviours.

  • Painful defecation.

• Faecal incontinence - passage of stool in inappropriate places:
  

  • Organic faecal incontinence - faecal incontinence resulting from organic disease.

  • Functional faecal incontinence - faecal incontinence without organic disease:
    

    • Constipation-associated faecal incontinence.

    • Non-retentive faecal incontinence - (no constipation associated). This is the passage of stools in inappropriate places in children over 4 years old with no evidence of constipation.

• Faecal impaction - large faecal mass (abdominal or rectal and assessed by abdominal, rectal or other methods of examination) unlikely to be passed on demand.

• Pelvic floor dyssynergia - the inability to relax the pelvic floor when attempting to defecate.

Epidemiology

• Constipation in children, from whatever cause, is very common worldwide⁴ :
  

  • Beyond the neonatal period, functional constipation accounts for more than 95% of cases of constipation in children.

  • Worldwide, functional constipation has a pooled prevalence rate of 9.5% (95% CI 7.5-12.1).

  • The peak prevalence is during the preschool years and is particularly common around the time of transition to solid foods, toilet training and school entry⁵ .

  • The median age of onset is 2.3 years.

  • Functional constipation is slightly more common in girls.

• Most children with constipation are developmentally normal. Constipation in children is seen commonly in:
  

  • Infants at weaning.

  • Toddlers acquiring toilet skills.

  • School age.

• Constipation in children may also be associated with problems with toilet training, psychological problems, major life events (although recent data from a Palestinian cohort show no difference in prevalence (relating to stressful event) than other populations⁶ ), neurodevelopmental disorders and autism.

Constipation in children symptoms (presentation)⁷

• History. In addition to general history (past medical history, school and social history and family history), the parent and child should be specifically questioned about the constipation. Parents can mistake incontinence for diarrhoea. In infants aged under 6 months, straining and crying for 10 minutes before passage of stools is caused by dyschezia (painful or difficult defecation which resolves spontaneously) and may be mistaken for constipation. Specific questions should cover:
  

  • The frequency of defecation.

  • Consistency of stools - this may include use of the Bristol Stool Chart⁸ .

  • Episodes of faecal incontinence.

  • Pain on defecation.

  • Whether stools block the toilet.

  • Any associated behaviour.

  
  Any pain on defecation is likely to lead to withholding. Toddlers and older children get better at withholding.

• Examination. This should include:
  

  • Palpation of the abdomen for faecal mass.

  • Inspection for anal stenosis or ectopia.

  • Looking for sacral abnormalities.

  NB:
  

  • Rectal examination is not routinely necessary or required.

  • Routine radiography is not recommended.

Causes of constipation in children (aetiology)^{7 9}

Organic causes of constipation

It is important to distinguish these organic causes from the much more common functional causes. Many of the organic causes will present in the first few weeks of life.

• Anorectal malformations:
  

  • Physical examination. Careful inspection of the perineum in any baby with constipation:
    

    • Is the anus in the correct position relative to the vulva or scrotum?

    • Careful digital rectal examination with the well-lubricated fifth finger is advocated by some (detect stricture, assess volume and hardness of rectal stool). However, this should only be undertaken by healthcare professionals competent to interpret features of anatomical abnormalities or Hirschsprung's disease¹ .

• Anal fissure is common and associated with painful defecation. Passage of blood and sentinel pile on the anterior anus are characteristic.

• Rectal prolapse may be caused, for example, by chronic straining and constipation, disorders of sacral nerve innervation and chronic diarrhoea.

• Hirschsprung's disease usually presents early (as delay in passing meconium, failure to thrive, etc) well inside the first month. However, rarely it can present late. Diagnosis is by:
  

  • Rectal biopsy - the test of choice.

  • Barium enema.

  • Anorectal manometry, which is NOT recommended¹ .

• Neurenteric problems:
  

  • Colonic motility - the test of choice.

  • Colonic transit.

  • Possibly rectal biopsy.

• Spinal cord problems:
  

  • Physical examination.

  • Magnetic resonance imaging - the investigation of choice.

  • Possible anorectal manometry.

• Pelvic floor dyssynergia:
  

  • Anorectal manometry - the test of choice.

• Metabolic or systemic disorders:
  

  • Hypothyroidism - TFTs.

  • Coeliac disease - tests for coeliac disease.

  • Hypocalcaemia - calcium test.

  • Cystic fibrosis - sweat test.

• Toxic:
  

  • Lead levels, toxicology screen.

• Cow's milk allergy:
  

  • Elimination diet.

  • Allergy testing.

Functional causes of constipation in children

Chronic constipation and other types of functional constipation:

• History and physical examination are most important in the assessment, and further tests are rarely necessary.

• Further investigations are recommended occasionally in chronic constipation and always in non-retentive faecal incontinence. Specifically:
  

  • Radiology (kidneys, ureter, bladder).

  • Colonic transit.

Diagnosis

Confirm that constipation is present⁷ :

In a child aged <1 year, at least two of the following:

• Fewer than three complete stools per week (unless exclusively breastfed when infrequent stools can be normal).

• Large hard stool or 'rabbit droppings'.

• Symptoms associated with defecation: distress on passing stool, bleeding with hard stool or straining.

• Past history of constipation.

• Previous or current anal fissure.

An older child may have the above, plus:

• Overflow soiling (the child may be unaware of passing loose, smelly stools, which may be thick and sticky, or dry and flaky).

• Large stools, big enough to block the toilet!

• Poor appetite that improves with passage of a large stool.

• Abdominal pain which waxes and wanes with passage of stool.

• Retentive posturing - eg, on tiptoes, straight-legged, and with an arched back.

• Straining, painful bowel movements, and/or anal pain.

Management (including any investigations)^{7 10}

History and examination are most important to make a diagnosis and should determine whether further investigations are required.

A useful flow chart to guide overall management is incorporated in the National Institute for Health and Care Excellence (NICE) guidance, emphasising the importance of identifying any amber or red-flag symptoms or signs¹ :

A summary of NICE guidance on constipation in children and young people¹

Management of functional or idiopathic constipation^{10 11}

This section is aimed at the management of functional or idiopathic constipation¹ . The aims are to remove faecal impaction, restore bowel habit (with soft stools passed without pain), self-toileting and passing of stools in appropriate places. Children and parents should be offered support through the treatment process.

Management plan

• Anxiety of the parent and child.

• Attitudes of guilt or blame.

• Inappropriately coercive toilet training.

• Social consequences (for example, faecal incontinence in older children).

The clinician should take a positive approach which is sympathetic, non-accusatory and with careful explanations and continued involvement and follow-up.

• Disimpaction. Retained faeces should be cleared from the rectum⁷ :
  

  • Initially, use an osmotic laxative - eg, polyethylene glycol (PEG) 3350 plus electrolytes (Movicol® Paediatric Plain). This may increase symptoms (eg, soiling) at first. Gradually increase the dose if ineffective. If not tolerated, substitute a stimulant laxative (see below) either on its own or with lactulose (osmotic laxative) or faecal softener (docusate) if stools are hard.

  • If ineffective after two weeks, add a stimulant laxative - eg, sodium picosulfate or senna in children over 1 month of age, docusate (softener and weak stimulant laxative) from 6 months of age or bisacodyl suppositories from 2 years of age. If success is not forthcoming, discuss with a paediatrician.

  • Rectal treatments should be avoided in children (suppositories, enemas, manual evacuation), although they may be recommended by specialists and in hospital.

  • Review the child at least weekly until successful.

• Maintenance therapy. This may incorporate:
  

  • Dietary advice, including intake of fluids and fibre.

  • Use of bowel charts and a diary for objective record.

  • Regular laxatives over months or even years, preferably osmotic (PEG 3350 or lactulose), titrated to maintain soft formed stool.

  • Avoiding stopping and starting treatment causing intermittent impaction.

  • Avoiding prolonged use of stimulant laxatives (causes atonic colon and hypokalaemia).

  • Using stimulant laxatives intermittently only to avoid impaction.

• Modification of behaviour. Behavioural principles are useful in management. Specific behavioural modification techniques can be employed in specialist clinics. In general:
  

  • Encourage regular, unhurried toileting.

  • Encourage use of reward systems for successful use of the toilet.

  • Encourage linkage of diary to reward system.

• Incontinence. Dealing with this requires:
  

  • Explanation to the parent and child of the involuntary nature of this.

  • Encouragement of regular toileting.

  • Involvement of the school nurse if possible to help with toileting and teacher education.

  
  There is no good evidence for psychological interventions despite some associations between incontinence and psychological problems.

Note that:

• Infrequent defecation increases the likelihood of pain on passage of hard stools, anal fissures, anal spasm and ultimately a learned response to withhold defecation.

• Chronic obstruction may cause the rectum to enlarge to form a megarectum, which has impaired sensation and decreased contractility, resulting in soiling.

• Regular bowel actions must then be established using dietary advice (fibre and fluid intake), regular laxatives and encouragement of a toileting pattern.

• Laxatives must be continued for many months and then gradually withdrawn. Relapses are common and should be treated early with increased doses of laxatives.

• However, evidence for the benefit of laxatives is weak but a Cochrane review found that polyethylene glycols (macrogols) may be more effective than placebo, lactulose or milk of magnesia for constipation in children¹² .

• A 2019 systemic review found 30 studies including 27 clinical trials and three case series. Ten documents were on herbal medicine, nine on traditional medicine, ten on manual therapies and one on homeopathy. Except for two herbal and one reflexology interventions, all studies reported positive effects on childhood constipation, with the majority being statistically significant. The number of studies in each method was limited so a meta-analysis was not performed¹³ .

• NICE advises against routinely referring children with idiopathic constipation to a psychologist or any other mental health services unless they have been identified as being likely to benefit specifically from a psychological intervention¹ .

• Very rarely, children may require enemas under sedation and even surgery to modify the anal sphincter¹⁴ .

Indications for referral

Specialist assessment is indicated if:

• An organic cause is suspected or there are any red flags (see NICE guidance table, above).

• Treatment is unsuccessful (ie no response in four weeks for a child aged under 1 year); refer (to exclude Hirschsprung's disease), or no improvement after three months in an older child⁷ .

• Management is complex.

• Child abuse is suspected.

When an organic cause is suspected, the GP can arrange for initial tests (such as inflammatory markers, thyroid function, calcium, tests for coeliac disease). Some specialists measure colonic transit time to differentiate:

• Soiling with normal transit time.

• Constipation and delayed transit time (worse outcomes).

Surgery is required rarely for the most severe cases of chronic constipation in children and overflow soiling. It can be important in intractable cases. Botulinum toxin has been used for short aganglionic segments of bowel and to provide temporary weakening of the sphincter¹⁴ .

Complications¹¹

Failure to correct functional constipation may lead to problems. For example, the following may arise:

• Faecal impaction.

• Chronic constipation.

• Megacolon (may predispose to, or result from, constipation).

• Rectal prolapse.

• Anal fissure.

• Faecal soiling.

• Psychological effects.

Prognosis^{7 15}

The prognosis of idiopathic constipation varies with each child and family:

• Constipation is more likely to become persistent if it develops in early infancy and the child has a family history of constipation.

• Outcomes are improved when constipation is identified and treated promptly - a delay in initial medical treatment of three months or more correlates with a longer duration of symptoms of constipation.

• Symptoms become chronic (duration longer than eight weeks) in more than a third of children, most commonly in children between 1-4 years of age (the pattern of bowel movement tends to be established by 4 years of age).

• Children with other illnesses, particularly psychological disorders, such as autism, or major psychosocial problems, tend to have a less favourable long-term prognosis.