Introduction

Constipation in children is a common problem affecting between 5% and 30% of children.¹ 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.¹ It accounts for some 25% of paediatric gastroenterologists' work and is also one of the 10 most common problems seen by general paediatricians. On a practical note, when faced with the casual request of a laxative for a child, think carefully. It is recommended that the child be seen for a proper assessment and diagnosis.

Epidemiology

• Constipation in children, from whatever cause, is very common worldwide and 90-95% of constipation is functional: ⁵
  • Prevalence ranged from 0.7% to 29.6%.
  • Prevalence rates were similar in boys and girls.
  • Age of highest prevalence could not be identified.
  • Socioeconomic factors were not found to be associated.
  • Further studies using newer diagnostic criteria were called for.
• Most children with constipation are developmentally normal. It is seen commonly in:
  • Infants at weaning.
  • Toddlers acquiring toilet skills.
  • School age.
• Often psychosocial factors may be involved or suspected. They may precede or maintain the constipation.⁶

Presentation

• 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 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 Chart.⁷
  • 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.
  Note:
  • Rectal examination is not routinely necessary or required.
  • Routine radiography is not recommended.

Aetiology

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.⁸

• Anorectal malformations:
  • Physical examination. Careful inspection of the perineum in any baby with constipation:
    • Is the anus in 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).⁴ However, this should only be undertaken by healthcare professionals competent to interpret features of anatomical abnormalities or Hirschsprung's disease.¹
• Anal fissure. This is common and associated with painful defecation. Passage of blood and sentinel pile on the anterior anus are characteristic.⁴
• Rectal prolapse. This may be caused, for example, by chronic straining and constipation, disorders of sacral nerve innervation and chronic diarrhoea.⁴
• Hirschsprung's disease. This 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.
  • Anorectal manometry, which is NOT recommended.¹
  • Barium enema.
• 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 - thyroid function tests.
  • Coeliac disease - tests for coeliac disease.
  • Hypocalcaemia - calcium test.
  • Cystic fibrosis - sweat test.
• Toxic:
  • Lead levels, toxicology screen.
• Cows' milk allergy:
  • Elimination diet.
  • Allergy testing.

Functional causes of constipation

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 constipation is present:⁹
In a child <1 year, at least two of the following:

• Less than three complete stools per week (unless exclusively breast-fed 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, e.g. on tiptoes, straight-legged, and with an arched back.
• Straining, painful bowel movements, and/or anal pain.

Management (including any investigations)

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 Clinical Excellence (NICE) guidance, emphasising the importance of identifying any amber or red-flag symptoms or signs:¹

Management of functional or idiopathic constipation

This section is aimed at the management of functional or idiopathic constipation.^1,9 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.

• 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.
• Children and parents should be offered psychological counselling and support through the treatment process. Older children may also benefit from biofeedback training.¹¹ However 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 intervention.¹
• Very rarely, children may require enemas under sedation and even surgery to modify the anal sphincter.¹²

Indications for referral

Specialist assessment is indicated if:

• An organic cause is suspected or there are any red flags (see above).
• Treatment is unsuccessful (i.e. no response in 4 weeks for a child under 1 year), refer (to exclude Hirschsprung's disease), or no improvement after 3 months in an older child.⁹
• 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 and overflow soiling. It can be important in intractable cases.⁴ Botulinum toxin has been used for short aganglionic segments of bowel and to provide temporary weakening of the sphincter.⁴

Complications

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

Long-term follow-up studies of children under the age of 5 referred to a specialist clinic showed 50% recovery within 1 year and 65-70% recovery within 2 years, with the remaining 30% or so requiring long-term laxatives, or continuing to soil.⁶ In another study, 30% of children continued to have severe constipation beyond puberty.¹³ Obviously, results from earlier treatment of less severe cases in general practice should be better than this.

Document references

1. Constipation in children and young people, NICE Clinical Guideline (May 2010); Diagnosis and management of idiopathic childhood constipation in primary and secondary care
2. Fontana M, Bianchi C, Cataldo F, et al; Bowel frequency in healthy children. Acta Paediatr Scand. 1989 Sep;78(5):682-4. [abstract]
3. Benninga M, Candy DC, Catto-Smith AG, et al; The Paris Consensus on Childhood Constipation Terminology (PACCT) Group. J Pediatr Gastroenterol Nutr. 2005 Mar;40(3):273-5.
4. G S Clayden, A S Keshtgar, I Carcani-Rathwell, A Abhyankar; Archives of Disease in Childhood Education and Practice Edition; The Management of Chronic Constipation and Related Faecal Incontinence in Childhood
5. van den Berg MM, Benninga MA, Di Lorenzo C; Epidemiology of childhood constipation: a systematic review. Am J Gastroenterol. 2006 Oct;101(10):2401-9. [abstract]
6. Baker SS, Liptak GS, Colletti RB, et al; Constipation in infants and children: evaluation and treatment. A medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition. J Pediatr Gastroenterol Nutr. 1999 Nov;29(5):612-26. [abstract]
7. Bristol Stool Chart
8. Nurko S; What's the value of diagnostic tools in defecation disorders? J Pediatr Gastroenterol Nutr. 2005 Sep;41 Suppl 1:S53-5.
9. Constipation in children, Clinical Knowledgs Summaries (September 2010)
10. Rubin G, Dale A; Chronic constipation in children. BMJ. 2006 Nov 18;333(7577):1051-5.
11. No authors listed; Managing constipation in children. Drug Ther Bull. 2000 Aug;38(8):57-60. [abstract]
12. Clayden GS, Keshtgar AS, Carcani-Rathwell I, Abhyankar A. The management of chronic constipation and related faecal incontinence in childhood - Best Practice. Archives of Disease in Childhood - Education and Practice 2005; 90: ep58-ep67 (subscription required)
13. van Ginkel R, Reitsma JB, Buller HA, et al; Childhood constipation: longitudinal follow-up beyond puberty. Gastroenterology. 2003 Aug;125(2):357-63. [abstract]

Internet and further reading

• Constipation in children, Clinical Knowledgs Summaries (September 2010)
• Bristol Stool Chart

Acknowledgements