Constipation in children

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You see a 3yo girl in your clinical setting with a 2 week history of intermittent tummy pain (she doubles up holding her abdomen, crying). She has a poo every couple days but this isn’t anything new. Parents have brought her in today because she seems particularly distressed and keeps going to the toilet.

In this weeks blog, we look at constipation in children and infants. It is a really common problem but it isn’t always easy to diagnose and manage, especially because we need to think about differently to adults.

I was once told by a paediatrician that “there is no such thing as a child with a little bit of constipation”. 

Young children are inherently prone to constipation! Why? Usually, it’s because they are children! Constipation in children (as in adults) is multi factoral. A lack of dietary fibre, sedentary life style, inadequate hydration, medication related, toilet training related issues, psychosocial and developmental factors all play a part.

All these factors aside, we then assume that children understand the sensations that lead to defecation. But this comes with development and maturity. As adults we understand and recognise the urge to defecate and act accordingly. Children have to develop an awareness about their internal sensations and what they mean, and until they master those sensations and get used to using a toilet, constipation will be a risk. NICE identify that the peak incidence of constipation is between 2-4yo (toilet training age) but has a high prevalence in those <11 yo (30% of UK children), having symptoms lasting <6months. 5% will have symptoms >6 months.

Constipation isn’t usually recognised by parents/ care givers as such until the symptoms are problematic, by which time the child has likely been constipated for weeks or months (bear with me, this will make sense). Check with caregivers what they mean by ‘constipation’. It seems obvious but people often use medical terminology incorrectly so its worth clarifying this. What do they mean when they say ‘poos are normal’?

The true meaning of constipation is passage of hard stool, often with straining, passage of stool may be infrequent, with a lack of voiding/ satiety. In an older child this will be far easier to ascertain than in a pre verbal or young child. The child may well be passing stool every day, but it might be hard/ large stool with straining. If they also don’t completely void, the bowel and rectum will stretch and ‘become baggy’ (think overstretched Tshirt- it eventually shrinks back but not immediately)

Clinical signs/ symptoms of constipation vary between children but can be subtle and easily dismissed or over looked. Recurrent UTI, new bed wetting in a previously dry child should prompt you to consider constipation. The NICE CKS on constipation in children outlines common features of constipation but I shan’t regurgitate them here because NICE have already done it for us. Lazy I know!

Distinguishing between constipation and faecal impaction will determine the treatment starting point. Stool in the anus, rectal pain, incontinence or faecal soiling, and faecal pass palpable in lower abdomen are all potential indicators. NB rectal examination SHOULD NOT be routinely performed to diagnose faecal impaction, largely because it doesn’t help and secondly because it is poorly tolerated and distressing for children. If PR exam is needed, the child probably needs to be seen by a paediatrician because you’re thinking that there is more than meets the eye. External inspection of the anus is appropriate (using judgement) and can identify fissures, inflammation, faecal mass in anus that can provide clues about the likely cause and clinical picture.

PR bleeding will usually cause alarm to parents/ carers understandably but is usually benign (anal fissure is common) in the constipated child (but lower your threshold for running this one past paeds in a very young child because it might be something more serious).

Infants- It is physiologically normal and acceptable for babies in the first couple of months of life to pass infrequent stool and they may appear to strain heavily or be distressed when defecating. Provided the stool is not hard/ pellet like, this isn’t constipation, but the rather horribly named dyschezia (medical term for normal baby bowel stuff). The caregivers will also associate these signs in themselves as constipation and extrapolate this to their child, but of course the anatomy and physiology of an adult is not the same as an infant. If constipation presents in the first few weeks of life without obvious cause, laxatives shouldn’t be started in the community and the child will need referring to paediatrics to exclude a serious underlying cause. If a benign cause is apparent (e.g. started infant gaviscon and constipated since) it may be appropriate to manage in the community, with a low threshold for having a discussion with on call paediatrician, depending on level of certainty and clinical judgement.

Breast fed babies are far less likely to develop constipation than formula fed babies (insufficient water used to make up formula, and use of thickeners/ alginates e.g gaviscon, the latter often over prescribed, will both contribute to constipation and is usually easily rectified). There is often a change in bowel habits when feeding methods change, from breast to bottle, weaning to solids etc. Once the bowel has ‘gotten used’ to this, bowel habits will usually return to normal. These are part of normal gut function and not necessarily a disease to treat.

Treatment of constipation is aimed at restoring regular, soft and easily passed stool, whilst allowing the lax bowel to shrink back to normal size. This usually means using laxatives for a period of 2-3 months AT LEAST with dosing titrated up/ down as required. Discourage early cessation when stool seems normal as they will have rebound constipation because the bowel is still lax.

Lactulose vs macrogol- Macrogols consistently out perform lactulose in terms of efficacy and early resolution, but the liquid volume may be an issue for some children (each sachet requires ~60ml fluid). Lactulose is commonly utilised in <1yo but it irritates the gut causing discomfort and diarrhoea. Lactulose is a synthetic sugar (lactose) that is not able to be digested infant guts (because they don’t produce lactase until ~ 1yr old) and so causes transient inflammation (it essentially causes enteritis). This is the same reason that <1yo shouldn’t have cows milk, therefore don’t give lactulose if child <1yo, simple! Use macrogol (e.g. movicol) instead.

If faecal impaction is suspected, starting on high dose macrogol but consider adding stimulant laxative (e.g Senna) if this fails to work within 2 wks (by works, it means improving rather than complete cure).

Whilst suppositories aren’t routinely recommended, they may help relieve stool stuck in anus/ rectum. This is sometimes described by parents as a ‘turtles head’ as the stool emerges and disappears as the child bears down unable to pass it.

Lifestyle measures will certainly help but shouldn’t be used alone (conversely in adults, life style changes are recommended as the 1st line treatment). Adding extra fruit/ veg/ fibre to the Childs diet and ensuring good fluid intake is key to sustaining ‘good bowel habits’. Avoid making the parents feel that they are feeding the child properly. If the ‘fussy’ child refuses to eat healthy meal options, then ‘going without’ (keep meal accessible if they change their mind) is acceptable instead of providing an alternative.. They will eventually unlearn the ‘fussy’ behaviour.

Addressing psychosocial or toilet training issues can all help. E.g. allowing child to have ready and unhurried access to potty/ toilet, positive reinforcement (star charts etc).

When to worry? There are of course indications that might suggest a more serious underlying cause and should be considered whenever you are presented with a constipated child. The urgency of referral will depend on the likely underlying cause i.e. same day admission if bowel obstruction is considered, whilst other red flags might be appropriately referred <2wks. If in doubt, speak to your local paediatric centre, they’re usually really helpful and accepting that non-paediatric specialists will need support sometimes.