Appointments: 01277 695688
Dr Nigel Meadows
Clinic for both general paediatric problems
and all aspects of paediatric gastroenterology

Constipation In Children

Constipation in children is very common, in the majority of cases it is short lived and does not prove to be a long term problem. Drinking more water and increasing fibre in the diet may be all that is needed to help. In some children if this persists it may, become a long term problem, leading to soiling or accidents.

What Is Constipation?

Constipation in children means:

  • Difficulty or straining when passing stools
  • Passing stools less often than normal. There is a great deal of variation in the number of stools that a child may pass in the day. Not all children go to the toilet every day, provided there is no straining and the poo is not hard, this is normal
  • Rabbit pellet like stools or large diameter stools are indicative of constipation. Available charts, such as the Bristol Stool Chart are a useful guide to stool types
  • Pain on going to the toilet, often associated with blood on the paper, can indicate an anal fissure. This is often associated with constipation, and if uncorrected may proceed to chronic constipation

Chronic Constipation

This means that the constipation has become severe and lasts for a long time. It is commonly associated with abdominal pain, straining, and in some cases accidents. In some children there is an active avoidance of going to the toilet. The child takes themselves off to a corner and appear to be trying to go with red flushed faces, or grunting. They are actually struggling to avoid going and the associated pain. This obviously perpetuates the problem, as when they eventually go its very painful reinforcing in the child's mind that defecation needs to be avoided! Some children will also stop eating, a normal reflex during meals is to feel the need to go to the toilet. The child quickly associates this with the unpleasant, experience and cuts down their food intake.

In the normal course of events poo passing into the lower part of the bowel or rectum, stimulates a reflex, and the need to go. The muscles around the anus relax to help the passage of the stool. If inconvenient, another muscle or sphincter is under voluntary control and can be contracted to stop the poo. If this happens repeatedly the rectum becomes enlarged (mega rectum). The result of this is a reduction in both the movement through the rectum, and a lack of sensation of the need when to go. The child quite genuinely does not know when he wants to go, bits of poo break off resulting in soiling, or accidents. The pressure of an enlarged rectum, puts pressure on the bladder which also sits in the pelvis. This results in poor bladder emptying resulting in difficulties with peeing and the increased risk of urinary tract infections.

Causes Of Chronic Constipation

There are some congenital problems that may result in constipation from birth or the neonatal period. Congenital anal atresia, where the anus does not develop is normally apparent on examination of the baby at birth, although there are some mirror degrees.

Hirschprungs's disease is a cause of constipation that develops almost from birth. The plexus of nerves within the bowel have not developed properly and result in constriction of the bowel to a varying length. The early sign of this is a delay in the passage of meconium, longer than the normal 24-48 hours. The diagnosis is made by a biopsy of the rectum to examine the nerve plexus. The treatment is surgical, with a resection of the involved area of the bowel. The disease is genetic, involving the genes needed for movement of the nerves during development of the colon.

The most common cause of constipation is idiopathic. In this situation an unpleasant experience, such as an anal fissure, or infection, stops the child going to the toilet. This progresses to the development of a mega rectum, and the subsequent effect on bowel motility as discussed as above. This aversive event can occur even in children as young as a couple of months.

Some children with milk intolerance may also develop constipation, Rarer medical conditions resulting in constipation include, hypothyroid disease, diabetes, and some drugs such as strong analgesics.

Investigations

In the majority of children tests are not required in constipation. Early onset or delayed passage of meconium probably needs a rectal biopsy for confirmation. X-rays are not routine, but in some children where treatment is difficult a transit study may be performed. This is simply carried out by swallowing a capsule, containing some plastic shapes, and then taking an x-ray 3 days later. The movement of the shapes, through the bowel can then be reviewed on an x-ray of the abdomen.

Treatment

Simple measures such as a good fluid intake, and fibre diet coupled with regular exercise, are important to help prevent constipation. Mild laxatives such as lactulose may be helpful in an acute state. However chronic constipation needs regular laxative medication. The aim is to soften the stool to prevent pain. There are two types of laxative stimulants such as sennakot, and picosulphate, these can cause pain if used when the stools are hard. Bulk laxative such as Movicol or lactulose are more commonly used in children. Routine use of suppositories or enemas are to be avoided in children, particularly if they are scared of going to the toilet. The treatment should not be stopped too early as the poor bowel sensitivity and movement will not have corrected. Many parents are worried about a dependency on laxatives, but a chronic situation is more likely to be produced by stopping early. The laxative treatment should be in conjunction with trying to introduce regular toileting, asking the child to sit on the toilet after meals particularly breakfast. A good sign that things are recovering is when the child experiences an urge to go i.e sensation has returned.

In the acute situation where the stools have become obstructed, a clear out is needed. This can now be carried out at home using increasing amounts of Movicol over a couple of days. This should only be started with medical help. In many cases this avoids the need of enemas and hospital admission.

In severe cases such as the child soiling going to school, and resistant to large doses of laxatives, more intensive treatment is required. In older children this may need investigation of the movement of the pressure and responses of the anus and rectum, with a sensor or manometer introduced into the anus. The aim of the treatment is to try to keep the rectum clear. Some of the newer enema systems are comfortable for the child and can be used on a regular basis (PIRISTEEN).

Alternatives are to relax the internal anal sphincter with Botulinum toxin, this aids the child to push. The effect wears off and may need repeating. A further approach is via operation where the appendix is brought out on the surface of the abdominal wall. This creates a stoma or connection about the size of a Biro point and can be covered by a plaster. A small tube is introduced alternate days and laxative infused while the child sits on the toilet (ACE procedure). This sounds very invasive, but very effective and rewarding to change around a child's life who has been soiling and bullied at school.

Newer possibilities are on the horizon such as stimulation, using a TENS like machine are being developed that seem to have promise, but so far are on clinical trials.

Take Home Message

Constipation in children is common. Do not ignore chronic constipation the long term effects are miserable for children and their families.