Constipation
Background
Although this might seem like a strange condition to dedicate an entire chapter to, constipation is such a common problem in childhood, and often underlies unexplained symptoms in children. Every child has a different bowel habit to the next child, so knowing whether a child is constipated is often difficult, and when you add this to the unreliability of reported bowel habit, it is easy to see how inadequate passage of stools can be easily missed.
It is commonly believed that children who become constipated eat mainly ‘junk food’, which is low in fibre, and that children who eat healthily have normal bowel habits. Experience demonstrates though that any child can become constipated and that most of these children do not usually have a clearly identifiable ‘reason’. Most children who become constipated do so apparently without a cause or underlying pathology.
To take an adequate history, one must first have a working definition of constipation. One possible definition is that constipation is the failure to pass stools in a physiologically adequate way, leading to adverse symptoms. The normal physiology is for the large bowel to produce formed stools, and for the rectum to evacuate these as soon as the rectum contains stool. Children who become constipated have a failure in that process, which may be due to poor diet, poor fluid intake or an underlying medical condition. While most childhood constipation can be labelled as idiopathic, diet and other factors often contribute. The processes governing opening ones bowels are complicated and the psychological/behavioural aspect to constipation is essential to understand.
When we are born, stool passage is a reflex neurological phenomenon. The fact that well babies can get constipated shows that this process can fail. Later in life we impose higher control over the function of our anal sphincter. It is therefore possible to override the desire to pass stool when higher control is learned and this ability can contribute to the development of constipation. Children will not open their bowels for a variety of reasons. They may simply withhold stools because they are too busy to go to the toilet; they have block towers to build and games to play. Often in constipation a vicious cycle develops because the hard stool causes anal discomfort and so the child is reluctant to go to pass stool for fear of pain. In fact, any negative association with going to the toilet, including criticism for soiling, can contribute to a child’s constipation problem.
It is also important to understand the impact that constipation in children has on the child and their families, especially in school age children. The effect on the family dynamic is often considerable and the daily attention given to the problem makes it into an anxiety of elephant proportions. The child’s self esteem and confidence is also affected. Child and parent alike end up feeling that they are failures. Your job is to turn this around.
How to assess
The first thing to realise is that many children with constipation do not present with constipation as such. The ways that constipation presents are many and varied including:
•Diarrhoea
•Abdominal pains
•Urinary frequency
•Urinary tract infection
•Soiling
•Poor weight gain
•Anaemia
The key to diagnosing constipation lies in thinking of it as a possibility and then asking the right questions. Examination may not be as helpful as you would hope, so a good history is essential.
•How often does the child open their bowels?
•How big a stool do they pass? Do they pass any small amounts between stools?
•What does the stool look like? This can be subjective, but essentially you want to know if it looks like animal droppings, a sausage or sloppy curry.
•Are they still in nappies?
•Do they soil?
•Ask about the specifics of diet and fluid intake.
•Ask about abdominal pain and its association with meal times and opening bowels.
•Ask about anal pain and bleeding.
•Ask about urinary symptoms and past urine infections.
•Ask about medications and family history of bowel disorders.
When examining the child, look for:
•General wellbeing, conjunctival pallor.
•Weigh the child and plot the result in their hand held record or a growth chart, and compare the total to previous weights.
•Abdominal distension.
•Abdominal tenderness and masses. (Faeces may be palpable, but not always easily. Sometimes they are soft, and so therefore difficult to feel. A fullness of the left lower quadrant is suspicious for constipation.)
•Examine the anus externally (do not perform a rectal examination), looking for soiling and fissures.
The ‘must do’s
Be specific about the history of the bowel habit. Do not accept the answer that it is ‘normal’. Find out how often and what the child is passing.
Get details about diet. The only way to adequately do this is to ask what the child has actually eaten and drunk in the past 24 hours, hour by hour.
Remember that trauma to the anus can be sexual abuse which itself can lead to constipation. Without other causes for concern, the anal fissure can be explained by the constipation; however, if there are other features which lead you to suspect abuse, include the constipation and anal fissure among these suspicious features.
Pitfalls to avoid
Avoid under-treating or partially treating constipation. By the time that they present for a medical assessment, children usually have well established constipation that requires adequate treatment for many weeks or months. Short bursts of laxatives temporarily improve things if you are lucky but may make matters worse and cause the family to lose faith in the treatment when the problem comes back. Do not be fooled by the fact that the child or parents have only been aware of symptoms for a short period. By the time things are bad enough to seek help, no minor intervention is likely to work.
How to be a know-it-all
The best way to be a bit clever about constipation is to diagnose it in a child with vague symptoms. At some point in your career you will see a child with weight loss, or abdominal pain or urinary symptoms and you will think, ‘I wonder if this could all be due to constipation?’ Ask a little bit about bowel habit and you may find that you are the first person who went into any detail. If you are the person who finally identifies the cause for a child’s symptoms you will find that the parents are very impressed.
A guide to the management of constipation
The management of children under one year old is a rather different matter to that of the older child. Babies can often go through periods of days where no stools are passed. Straining and going red are normal features of infancy, just as colic is. If they are significantly symptomatic then they are best managed by adding water to their intake, and ensuring this is offered between feeds and not before a feed so that the child still gets the calories that they need. If the baby seems to be getting distressed by the constipation, then a glycerine suppository as well as water may allow the child to pass a stool and help to get things moving. The size of this will depend on the size of the baby. The current British National Formulary for Children (BNFc) recommends a 1 mg suppository between the ages of one month and one year. Before one month, suppositories are rarely needed. If you do need to use glycerine, you will often need to repeat the dose. I tend to avoid lactulose as it is metabolised to rather unpleasant chemicals, potentially causing more discomfort.
Fruit juice has also been traditionally recommended. Some advise fresh orange juice and some recommend prune juice. There is in fact very little evidence that these are effective or indeed as to how they work if they do work. It may be that any laxative effect is due to poorly absorbed sugars in the fruit juice rather than a fibre effect as most would assume. Since giving water is just as lacking in evidence but is presumably less likely to do harm, I would recommend a preference for simple water (sterile water for babies) in the first place.
The wonderful thing about treating constipation in older children is that anyone can do it if they have the confidence and they are willing to spend the time. Even if you are only seeing the child as a one-off, such as in the emergency department, or an out-of-hours GP service, it is possible to make a real difference to what is a long term problem which has a huge impact on families.
Education and advice
The first stage of treatment is explanation. Understand that ‘constipation’ will not adequately explain the problem. Enthusiastic explanations of how our bowels are supposed to work and a description of what happens when things go wrong are vital to getting the child and parents on board for the necessary changes which will hopefully resolve the problem. I find that pictures are useful and some ready made pictures are available from various sources. However, because I am not that well organised, I usually draw my own (see Figure 8.1).
At the end of your explanation, the parents (and child if old enough) should understand the following:
•Constipation happens commonly in childhood, and usually for no particular reason.
•The problem is usually there for many weeks or months before anyone realises that this is what is going on, so it is unlikely that the problem will go away on its own.
•Usually, poo moves through the tubes in the tummy and when it gets to the end of the tube we feel it there and push it out into the toilet.
•When we get constipated, there is poo that is not coming out when it should.
•This poo stretches the tubes, making the muscles in the tummy weak, and numbing the nerves which are supposed to tell you when to poo.
•There are lots of things that can be done to make this all better but it will need you to work hard to make it better.
•It may take just as long for you to get better as it took for the problem to sneak up, so this will take several months to get it properly better. Remember the stretched muscles and nerves that I told you about: they need time to get their strength back.
Figure 8.1 Normal bowels: an explanation of how bowels usually function
Hopefully, you will now have a captive audience who understand the problem and are eagerly awaiting your advice. There is a lot of advice to give but don’t let that put you off. It is the simple things which make the most difference in the long term, even if they do need medication in the medium term. Good advice is important, and should be repeated at each visit, as it is quickly forgotten. Also, if it is emphasised at each contact with a health professional, the family will better appreciate the sincerity of this advice. If possible, write it down and ask the child to repeat back to you what the important bits were. The key points are:
•Even if diet may not be to blame (this is important to emphasise because no parent believes that they feed their child poorly, so by implying that they do, you have immediately lost your rapport), there are certain things that help constipation get better and some things that make it worse. Bad foods for constipation include chocolate, crisps, sweets, biscuits and cakes. Good foods are fruit and vegetables and cereals with lots of fibre in them. Unfortunately you have to eat the good foods, and get rid of the bad foods.
•Drinking water is also important. Milk is healthy for bones, however drinking nothing but milk can make you constipated. Sugary and fizzy drinks are very bad for constipation. Pure orange juice can help a little bit, but nothing is as good as drinking lots and lots and lots of water.
•Because the nerves are not working as well as they should, they don’t always send the message that you need a poo. But, when you have just had a meal, your body gives out a chemical that makes the muscles in your tummy stronger. So the best thing to do is for the child to sit on the toilet for at least five minutes after every meal. Encourage the child to do a poo but tell them not to become upset if they don’t. The more a child spends trying after meals, the sooner the nerves will work again.
•Because the muscles are all stretched and weak, this problem usually needs help to begin with to get better. The medication that we use makes the muscles stronger, and keeps the bowels empty enough to get their strength back. Because this takes time, children usually need to take the medicine for a few months. If the child stops the medicine as soon as it has started working, the muscles are still weak and the problem quickly comes back.
Medication
The issue of medication is seemingly a thorny one. There is a belief that use of laxatives creates dependence. I believe that this misconception exists for two reasons. Firstly, laxatives only temporarily improve bowel function. If therefore the problem is not a temporary one, the problem returns on stopping the medication. Secondly, medication is stopped too soon too often so that the child has little hope of good bowel function. Both situations give the impression that the child has become dependent.
The solution is to treat for long enough to allow good bowel function to develop, and at the same time, ensure all that can be done is done to ensure that long-term, pro-constipation factors such as poor diet, fluid intake and bowel habit are removed from the equation.
The issue of which medication to use is a matter of personal preference:
•Glycerine suppositories are best used in the children under one year old. They work by lubricating the area where they dissolve, so make little or no difference to a child with proper constipation. However the effect that they have is slightly greater for very small children and using glycerine may avoid the need for other medication.
•Medications such as lactulose should rarely be used. Lactulose is a sugar which, as well as having an osmotic effect, is digested by gut bacteria, producing caustic chemicals which stimulate bowel peristalsis. This results in colicy pains. As a sugar, it causes tooth decay and has caused many a child to have serious dental problems. Additionally, where there is overflow or soiling, the softening of the stools will make this worse, sometimes leading to accidents.
•A stimulant is almost always needed to help the bowels to clear the large hard stools which are causing so much of a problem. The choice of stimulant will depend on what you or your department are used to. Most clinicians now use macrogol laxatives first line. Whenever prescribing a stimulant laxative, you should advise two things. Firstly, that this will probably be needed for several months. Secondly, after starting the medicine, there may be a worsening of tummy pain and incontinence. This is because the muscles are starting to work again. It is therefore a good idea to avoid school time when starting stimulant laxatives if a child has significant constipation. Usually this effect only lasts a couple of days. The aim after any initial ‘clear out’ is to give adequate doses of enough stimulant laxative to allow them to easily pass a soft, well-formed stool on most days. This needs to be continued as long as it is needed. Eventually, as tone and sensation improve, the child should find themselves over-medicated and wean themselves off.
Now this needs to be followed up. If the child has been seen in the out-of-hours GP service or emergency department then the next step is probably to get the parents to book the child an appointment with their own GP. Ideally they will need something in writing to take with them to make sure that the doctor who sees them understands your plan. The most important decision to be made at the early follow-up is whether to increase the dose. Often, this needs to be done a few times before the constipation begins to resolve. Once passing formed stools, the child can be reduced to a maintenance dose. Their GP can then decide whether they feel equipped to follow through with the management of the constipation, or refer to a paediatrician for ongoing care.
De-mystifying the role of the paediatrician: what the paediatrician might do
Children can be referred to a paediatrician at any point for help with managing their constipation. Even so, most children are managed without tests or prescribing medications which are not licenced for use with children. Most of what the doctor does in the paediatric clinic can be done by any doctor who follows the management guidelines stated previously.
Occasionally children will have investigations, but this is the exception rather than the rule. Children should probably be referred for assessment if they remain on medication for more than six months or if they do not improve despite moderate doses of stimulant laxatives.
The services of a nurse specialist may be available in secondary care. Because constipation is such a common and persistent problem in child health, many trusts employ a nurse with a special interest in managing constipation. These nurse specialists are a valuable resource and can spend more time explaining the problem and treatment, as well as being a contact point for the family when needed.
FAQs
How long does constipation need to be treated for?
I was taught in medical school that using laxatives for prolonged periods leads the bowel to become dependent on treatment in order to work. In fact, I don’t believe that there is any evidence that prescribing laxatives somehow causes the bowel to forget how to work. The reason why people become constipated after stopping laxatives is that whatever caused them to become constipated in the first place (whether dietary, behavioural or pathological) is still there, causing the problem to recur. Imagine if we applied the same approach to conditions such as diabetes and stopped medication early for fear of tolerance!
I believe that a good rule of thumb is to assume that your patient will need treatment to be given for as long as they have had constipation, including all the time that they didn’t realise that this was the case (you can usually deduce this from the history, from the onset of related symptoms such as abdominal pain). Usually this means months rather than weeks of treatment. I believe treatment is needed for this long because it takes a long time to reach the point where bowels are functioning so poorly that people will seek medical attention. It will therefore take a long time to restore normal function.
What do I tell the parents?
When I have said that I think that their child is constipated, and they say that this is impossible because their child does poo sometimes:
‘Constipation is to do with what is stuck inside rather than what comes out. Often, children who are constipated do poo but not enough is coming out properly to keep things as empty as they need to be, to keep the bowels healthy. I like to think of this as a bit like traffic jams. Imagine that you are in a traffic jam that takes you an hour just to get to a set of traffic lights. If you are a pedestrian stood at the traffic lights, you will see lots of cars coming through, but there is still a mile long queue of cars. Constipation is like this. Some poo is coming out but it is what is waiting to come out which causes the problem.’
Flowchart for assessing the child with constipation
Figure 8.3 Flowchart for assessing the child with constipation
Summary for constipation
•Constipation is a common, often unrecognised problem in children, and causes significant long-term problems to the children who are affected as well as their families.
•Most constipation is not due to an underlying cause, and in the majority of cases, children can be managed in general practice without need for investigations. It is normal for babies to strain at stool and fail to pass stool for several days at a time. Significant constipation is uncommon in babies and may need referral.
•The key to treating the child with significant constipation is to give adequate doses of enough stimulant laxative to allow them to easily pass a soft, well-formed stool on most days. This should be continued as long as it is needed.
•All children with constipation need to understand the problem and the treatment. Child and family alike need to be motivated to ensure good diet, good fluid intake and good bowel habit.
•Every clinical contact with a child who has constipation is an opportunity to check that everything is being done to optimise diet, fluid intake, bowel habit and exercise, and that this is fully understood and implemented.
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