Why I have reservations over chloramphenicol going OTC
With constipation and soiling being responsible for 10 per cent of paediatric outpatient referrals, the problem needs to be taken seriously and intervention made early, advises Dr Anne Dale
There are numerous reasons why a child may become constipated or soil, and the age is important in deciding the underlying cause. Toilet training in childhood is all about the learning of external sphincter control as a consequence of reinforcement of the social value of continence. The child eventually learns to override the urge to pass stool until they are in a socially acceptable place.
In infants and newborns the earlier the onset of constipation the more likely there is to be a structural cause such as Hirschsprung's disease, anal stenosis or spinal nerve damage. If the normal neuronal pathways are absent, the child is unlikely to acquire normal continence.
If problems are later in onset and the child has had a period of normal bowel habit, then structural problems are extremely unlikely. Indeed it is generally accepted that if the age at onset of constipation is later than the neonatal period, then a rectal biopsy is unnecessary1.
Children of all ages, but especially those being potty trained, will frequently go through a phase of holding on to their faeces, which can produce hard and dry faeces. This also occurs during periods of illness.
Some children may resist further passage of stool if they have had a painful experience of defecation. Others may resist in response to developing a dislike of toilets at home or outside. Some children genuinely dislike the sensation of passing stool or sitting on a toilet. Other children will hold on to faeces as a response to other stressful events in their lives or in anger, and for some this will become excessive and result in significant faecal loading.
Holding on to faeces for long periods can result in fatigue of the external sphincter. The rectum then also becomes distended, which has the unfortunate consequence that ever-increasing volumes of faeces are needed to stimulate the rectum to contract for subsequent episodes of stool passage.
There is some sympathy for the idea that there may be congenitally different rectal capacities, which also predisposes a child to such a complication2.
There is also a group of children in whom for numerous reasons toilet training is delayed and these children frequently develop the ability to hold on to faeces excessively. At the time of presentation many children will report long periods, often lasting several weeks, without passing stool, although they may of course experience soiling.
A description of the stools they do pass can be helpful and the Bristol stool chart http://tinyurl.com/8vm52 (see page 9 of this online document) is a wonderful aid for children who find it easier to point to a picture than to describe3. Many parents will give a detailed description of large stools that block the toilet or bring tears to a dad's eye!
The presence of large amounts of faeces in the rectum can often precipitate soiling. This occurs because of pieces of stool breaking off from the larger mass or because of overflow of soft stool around the large stool in the rectum.
This is frequently interpreted by parents and indeed doctors as being deliberate by the child, but in this instance the child has no control over soiling and it is vital that this is recognised. In clinic we often hear tales of children being punished and ridiculed because of their soiling.
A child may manage to be clean for several days after passage of a large stool and then begin soiling again as the stool volume in the rectum once more increases.
School life can be seriously disrupted. The expectation is that a child over the age of five is continent, and a child who cannot prevent soiling is often misunderstood.
For older children the state of school toilets, which are almost universally less than satisfactory there is often a lack of privacy and poor hygiene often puts them off using the toilet during school hours.
Parents and relatives are often desperate by the time of referral because of the endless washing, offensive smell and failure to make any progress.
Diagnosis and treatment
It is important to first recognise whether the child has a distended rectum and is loaded with faeces, and the history is the most useful tool in deciding this question. Examination can also be helpful, especially if the child is loaded with faecal rocks, but it is not always easy to interpret what the examination reveals.
It can also be difficult to persuade some parents that a child who passes large amounts of stool into their underwear daily is constipated. An explanation of the pathophysiology may help to convince them.
Once the decision is made that a child has some degree of constipation, treatment with laxatives will be required. Softeners in the form of lactulose are useful in children and compliance is not usually an issue.
Stimulants are then needed and senna is effective and easy to take. Other softener and stimulant laxatives are useful also, including docusate sodium, bisacodyl and even liquid paraffin has been very effective in some units as a sole agent4.
The treatment pathway just outlined is one possible option, and there is little evidence to say one regime is much better than another. The important thing is adherence to a clear plan of management and increasing doses of treatment regularly as required.
Many children will need treatment with laxatives for years, and often families have to be reassured that no long-term damage results. A minimum of three-six months of successful treatment before attempting to reduce treatment is a useful guide.
If a child has huge amounts of faecal loading on examination, sometimes a thorough clean-out using a polyethylene glycol solution, which can be easily swallowed, is very effective. It can be taken at any age, especially if it has juice added, and it has produced results better than standard regimes in a few studies5,6.
Maintenance with polyethylene glycol solutions is not yet routine, but it can be considered.
Enemas and suppositories
These are not needed routinely, although they may occasionally be required as a last resort. They can serve to increase a child's fear or discomfort and lead to mistrust of staff unless they are able to fully understand and co-operate with the procedure.
Laxative treatment alone is not enough and it is vital that a toilet regime is established. The way to do this very much depends on the age of the child. A regular sitting habit of twice per day for five minutes with specific advice about pushing is a good starting point.
For younger children the use of star charts and rewards can help, and for older children the knowledge of what is wrong with them and understanding that they don't have normal rectal sensation is often enough encouragement for them to follow the toilet regime.
Regular and sympathetic support will contribute to compliance.
Children and parents need to be spoken with on a regular basis, and two-weekly meetings in the immediate period of starting treatment is a reasonable guide.
Anything less than this is insufficient to offer support and to change treatment. Once the child is stable, the frequency of follow-up can be reduced.
1 Ghosh A, Griffiths DM. Rectal biopsy in the investigation of constipation. Arch Dis Child 1998;79:266-8
2 Clayden G, Agnarsson U (Eds). Constipation in childhood. Oxford: Oxford University Press, 1991
3 Heaton KW. The Bristol Stool Form Scale, University of Bristol 2000. Produced by Norgine Ltd
4 Sharif F et al. Liquid paraffin: a reappraisal of its role in the treatment of constipation. Arch Dis Child 2001;85:121-4
5 Pashankar DS, Bishop WP. Efficacy and optimal daily dose of daily polyethylene glycol 350 for treatment of constipation and encopresis in children. J Pediatr 2001;139(3):428-42
6 Loening-Baucke V. Polyethylene glycol without electrolytes for children with constipation and encopresis. J Paed Gastroenterol Nutr 2002;34(4):372-7
Anne Dale is general paediatrician at the Queen Elizabeth Hospital, Gateshead
Find the full version of this article in The Practitioner, free with your copy of Pulse next week