Paediatric Constipation

Constipation is very common, affecting 5-30% of children at any one time. It is something we should be routinely screening for in our paediatric histories, regardless of our speciality.

Whilst constipation is most often idiopathic, we must be aware of potential underlying, organic causes, particularly in children under 6 months.

Causes of paediatric constipation

  • Functional/idiopathic constipation – most common!
  • Hirschsprung disease
  • Anorectal anatomical abnormality eg. imperforate anus or abnormal position of anus
  • Perianal skin infection
  • Anal fissure
  • Spinal cord abnormalities eg. tethered spinal cord, spina bifida
  • Myotonic dystrophy
  • Cow’s milk intolerance
  • Cystic fibrosis
  • Coeliac disease
  • Crohn’s disease
  • Hypothyroidism
  • Medication induced – typically opioids
  • Sexual abuse [1]


The first thing is to establish is whether the child does indeed have constipation. 2 or more positive findings from the question list below, indicate your patient has constipation:

  • Passing fewer than 3 complete stools in the average week

“Complete stools” are a 3 or 4 on the Bristol Stool Chart (see below)

  • Having stool that looks like rabbit poo (type 1 on the Bristol Stool Chart)
  • Infrequent stools that block the toilet
  • Passing loose stool without being in control, or aware, of it

This is ‘overflow soiling’, these stools tend to be loose, very smelly and are passed without sensation

If constipation is diagnosed, it is important to ask about associated symptoms, and to screen for the all-important red flags.

Constipation 1

Bristol Stool Chart [2]

Associated symptoms

  • Needing to strain to pass stool / distress on passing stool (particularly in <1 years)
  • Bright red blood on wiping after passing stool
  • Pain on passing stool
  • Abdominal pain that improves after passage of stool
  • Poor appetite that improves after passage of stool
  • Retentive posturing – this is where the child contracts the gluteus muscles to preserve continence, resulting in a straight-legged, back-arching posture

It’s also worth asking about previous episodes of constipation, as this makes the diagnosis more likely!

Consiptation 2
Child exhibiting retentive posture. [3]

Screen for red flags

Red flags are findings that indicate there may be an underlying condition which needs addressing. If there are any red flags for constipation in your history, you do not treat the constipation and instead, urgently refer to the indicated speciality, depending on your concern.

Red flags for constipation:
  • Failure to pass meconium, or >48 delay to pass meconium (in term babies). Possible causes:
    • Hirschsprung disease (aganglionic cells lead to functional obstruction as peristalsis cannot happen in the gut)
    • Bowel obstruction – the infant may also present with bilious vomiting +/- abdominal distention
    • Malrotation – will often present with bilious vomiting
    • Meconium ileus*– meconium obstructs the terminal ileum, this should prompt cystic fibrosis testing as it’s the most common neonatal presentation of cystic fibrosis!
    • Intestinal atresia – often this is diagnosed on antenatal scans, although can also present after birth, there may be a history of polyhydramnios (too much fluid in the womb) antenatally
    • Other small bowel obstructions eg. duodenal atresia and volvulusAnorectal malformations which prevent the passage of stool eg. imperforate anus.
    • Or simply prematurity! Delayed passage of meconium is common in premature and low birth weight infants due to factors such as delayed first feeds.
  • Constipation since birth
  • Ribbon stools (long, stringy stools) – another sign of Hirschsprung’s disease
  • Faltering growth – always remember to ask about a child’s general growth, development and wellbeing from birth to present
  • Lower limb neurological signs eg. leg weakness, delay in achieving crawling/walking milestones may point towards a ‘neurogenic bowel’. This is where neurological problems cause slow gut motility and reduced or absent sensation of the rectum being filled with stool. Possible causes include:
    • Cerebral palsy
    • Spina bifida
    • Acquired brain and spinal cord injuries
  • Abdominal distention and vomiting – ask if the child has been passing flatus (farts). If not, you should have a high suspicion for bowel obstruction. A history of previous abdominal surgery should also raise your index of suspicion for obstruction, as these children are at risk secondary to adhesions.
  • Social factors – any suspicion or disclosure of child abuse

Idiopathic constipation:

The vast majority of children will have idiopathic constipation, which means that there is no known cause or underlying illness. These children will have no red flags.

History findings indicating idiopathic constipation include:

  • Normal passage of meconium, which is within 48 hours of birth in term babies
  • Normal growth and development
  • Lifestyle causes of constipation, e.g. poor diet with little fibre or fresh fruit and vegetables, poor fluid intake, inactive lifestyle
  • Identifiable precipitating factors to the constipation e.g., illness, life stressors (e.g. changing school), fear of using the bathroom away from home, anal fissure (this makes it very painful to pass stool, so the child avoids defecating) and new medications
  • A change in infant formula, ceasing breastfeeding and weaning can also be precipitating factors for constipation in younger children

You may find it is easier talking to young children about their bowel habits compared to teenagers and adults, as younger patients tend to be much more open! Make sure to use terminology the child understands and is comfortable with. I like to start by asking the child (if age appropriate) what the problem is, and then use the words & phrases the child has used themselves throughout my history taking. This helps to keep the child involved throughout.

Remember to always take parental concerns very seriously; the parents know the child best!


As always with paediatrics, try to be opportunistic with the order of your examination.

  • Growth charts – looking for any faltering of growth
  • Dysmorphic Features – look for any signs of dysmorphism that could indicate an underlying syndrome. For example, Downs syndrome is associated with Hirschsprung’s and intestinal atresia’s.
  • Abdominal examination
    • Assess for abdominal distention
    • Faecal mass, particularly in the left iliac fossa can be present in constipation
  • Inspection of the perianal area – position of the anus, fissures, skin tags, bruising, excoriations and presence of any stool should be noted. Always consider using a chaperone when performing intimate examinations.
  • Lumbosacral region examination – assess gluteal muscle flattening and symmetry, scoliosis, discoloured skin, hairy patch and dimples you can’t see the bottom of (can indicate underlying spinal dysraphism)
  • Lower limb neurological examination – gait, lower limb deformity, strength, tone, reflexes and sensation should be tested, as well as looking specifically for any features of cerebral palsy [4]


The majority of children with constipation will not require investigations.

If the child has evidence of faltering growth, we should always test for coeliac disease and hypothyroidism. Appropriate blood tests in this scenario may include: FBC / Calcium / TTG and total IgA / TSH, T4, T3, TPO antibodies.

We DO NOT use imaging to diagnose idiopathic constipation. Remember to consider imaging as ‘radiation prescribing’ and take the decision seriously, particularly in young patients where radiation can have long term consequences later in life.


Management of constipation relies first upon identifying whether impaction is present. Overflow soiling and a palpable abdominal mass can be indications of this. Treatment of impaction can initially increase symptoms of soiling and abdominal pain, and it is important to warn parents and children of this.

See the management algorithm below:

Constipation 3
If polyethylene glycol 3350 + electrolytes is not tolerated, substitute a stimulant laxative eg. senna or bisacodyl with or without an osmotic laxative eg. lactulose [5], [6]

Disimpaction regime with Polyethylene 3350 plus electrolytes (macrogol)

Constipation 4
Table modified from NICE [7]
  • Disimpaction has been achieved when one or two soft, formed stools are produced each day. Once achieved, prescribe Movicol at the maintenance dose, which is half the disimpaction dose. Adjust the dose according to symptoms, for example reducing the dose if the child has diarrhoea.
  • Remember to advise that Movicol should be taken with water, NICE suggest that mixing it with fruit squash may help improve adherence. It is also sensible to advised to ensure good fluid intake throughout treatment to help avoid dehydration which can occur with laxatives.
  • Note that the use of Movicol Paediatric Plain to treat faecal impaction is off licence in under 5’s. The above regimes are also off licence for 5-18 year olds due to the high doses required for disimpaction. When prescribing drugs off licence, ensure you explain this to the patient/career and gain and document verbal consent. [8]

To whom should I refer for further investigation?

  • General paediatrics – any child presenting with faltering growth
  • Paediatric surgeons – any baby with bilious vomiting, failure to pass meconium in 48 hours or an anorectal malformation
  • Paediatric neurologist – any child with neurological signs. These may be indicative of cerebral palsy, spina bifida, brain or spinal cord injuries, all of which can cause, or contribute, to constipation. These children may require further referral for specialist assessment.
  • Child and adolescent mental health services – for children with psychological issues relating to the symptoms of constipation, or family difficulties that exacerbate constipation
  • If you suspect a child is at risk, you must act according to your local safeguarding procedures without delay. This will often involve sharing information with a named professional who will escalate to the appropriate agencies. Be careful to take detailed notes whilst the situation is fresh in your mind and consider the safety of any other children in the household. All doctors have a duty to safeguard children, and as a non-specialist it is simply your role to recognise the possibility of harm and to escalate appropriately.

Direct parents and carers to eric for more information and advice

Resources used:

[1]B. SM, “Paediatric Constipation Differential Diagnoses,” 5 March 2023. [Online]. Available:,%5D%2C%20cerebral%20palsy%20%5Bstatic%20encephalopathy.
[2]M. S. K. D. Harvey S, “How to Use the Bristol Stool Chart in Childhood Constipation,” Archives of Disease in Childhood: Education & Practice, 2022.
[3]K. K. Kahana DD, “Constipation,” 5 March 2023. [Online]. Available:
[4]NICE, “Constipation in Children and Young People: Diagnosis and Management,” 5 March 2023. [Online]. Available:
[5]C. C. B. C. LaznerM, “The Alex Emergency Department, Paediatric Practice Guideline. Management of Constipation in CED,” 5 March 2023. [Online]. Available:
[6] C. Belking-Gerson J, “BMJ Best Practice: Constipation in Children,” 5 March 2023. [Online]. Available:
[7]NICE, “Constipation in Children: Doses and Titration of Laxatives,” 5 March 2023. [Online]. Available:
[8]eric, The Children’s Bowel and Bladder Charity, “Information & Advice”. 5 March 2023. [Online]. Available:

Written by Katarzyna MacDougall, Final Year Medical Student, University of Birmingham

Edited by Dr Rebecca Evans, Paediatric ST3

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