POSITIVE Parenting

Understanding how constipation starts and is maintained is crucial to understanding how to treat it. Most cases of paediatric constipation develop because the child starts to repeatedly hold unto his stools for some reason. Common reasons include:

Infants - dietary changes (switching from breast milk to formula; starting solid food)

Toddlers - potty-training

School-age children - school.

Whatever the reason for holding on to stool, the result is the same: the colon continues to draw water from the stool. The longer the stool is held, the drier and harder it gets. When the child finally passes the stool, passage is painful and difficult. As the reason for holding continues, this is repeated. The child eventually associates passing stool with pain and when he gets the sensation to stool, he will hold on to it rather than pass it out so as to avoid the pain. (Many times parents misinterpret attempts to hold stool in as attempts to pass hard stool).

With repeated holding more and more stool gets stored in the colon. As this continues over a long period the rectum becomes stretched and the external sphincter which helps to control stool can become weak.

Successful treatment of constipation involves two stages:

1. Evacuation of retained, hard stool

2. Maintaining regular stools

Evacuation

All the hard stool that is 'backed up' in the rectum has to be cleaned out. If not, then as medication used for constipation makes the new stool soft, it will run around this hard 'plug'. This may be mistaken for a good response to medication but the hard stool remains and constipation is still a problem. As the external sphincter is weak medication may cause embarrassing accidents if hard stool is still there.

Maintenance

After evacuation, this child is left with a stretched out rectum which has lost its tone and doesn't work well anymore. If treatment is stopped at this point, new stool will enter this lazy rectum and be held as before. In time you will be back where you started. Once cleaned out, it is crucial to keep stool soft and easy to pass. Regular stooling following a clean-out accomplishes two things:

a) Eventually, the child realises that stooling doesn't hurt anymore and stops 'fighting' it. This prevents a further backup of stool.

b) As no stool is stored, there is nothing to keep stretching the rectum. Over time it will return to its normal size and tone and work normally again.

How are these steps accomplished?

Evacuation: Standard treatment is a daily enema for three consecutive days. If the return from the last enema is essentially liquid, without chunks of stool, then clean-out should be effective. If it is still solid in parts an extra enema may be needed.

Maintenance: Mineral oil or lactulose may be given on a daily basis. These agents are not absorbed by the intestines. As they pass down the intestines they pull water into the stool to keep it soft and harder for the child to hold on to. The dose can be adjusted to desired effect. To work along with the medicine the child must practise trying to pass stools after meals (even if he doesn't feel the need to) to retrain the intestines. If the child is not potty-trained, training should be delayed until after stools are being passed without pain or anxiety.

How long does the child need to be on medication?

This depends on the child and how long constipation has been a problem. If the rectum has been stretched out for months or years it will take a fraction of the time to regain normal function. So the longer it's been a problem, the longer it will take to get off medication. Stopping too early will result in stool backing up and becoming a problem again. Inconsistent medication will do the same. Some younger children will continue to try to hold on to stool even when it is soft, as they anticipate that it will still hurt. Once they still try to fight against stooling the medication cannot be stopped. When they do stop, medication should be continued for several months before decreasing the dose or stopping it altogether.

Treatment should be under the direction of a doctor and will vary for infants.

Dr Kirk Thame is a paediatric gastroenterologist.