Constipation Is a Chronic Condition, and It Requires Treatment for a Long Time
3 February 2004
Q. We are worried about our four-year-old son. He became constipated
shortly after we started toilet-training him. He would hide behind
the chair when he needs to have a bowel movement. Sometimes we
see him dancing around or crossing his legs when he needs to go to
the toilet. When he finally does, his stool is so large in size
that it would plug up the toilet. In the last two months, we have
seen some loose stool in his underwear. He said that he didn't
know it until after it had happened, and he would deny it even
though all of us could smell it. We are concerned that the problem
will get worse next year when he starts kindergarten. Can you
please advise us what we can do to control this constipation problem?
A. From your description, your son developed constipation
when you started toilet-training him. This problem has progressed
over the past two years to the point when liquid stool starts to
leak around the constipated stool. This is called encopresis, and
is a serious consequence of long-standing constipation. Your son
definitely recognizes his problem, although he doesn't know how to
help himself. The problem of passing gases (due to constipation)
and the smell of encopresis will result in serious emotional trauma
unless help is given to him very soon.
Constipation is the name used to describe infrequent bowel movements
that are hard in consistency, and large in size or diameter. The
frequency of bowel movement, and the size and consistency of stool
varies depending on age and the kind of food consumed. Before
going any further, I will discuss briefly about the function of
our intestines so that you can understand how and why constipation
happens.
When food is taken into the mouth and swallowed, it passes through
a long tube called oesophagus into the stomach. Some digestion
occurs there, but most of it happens in the small intestines.
After digestion and absorption, whatever that remains from the
ingested food is passed into the large intestine (also called the
large colon). The main function of the large colon is to finish
the absorption of nutrients and water. Inside the colon, food
remnant is converted into stool to be eliminated through the anus.
Just above the anus is the part of colon called rectum. When about
one tablespoon of stool enters the rectum, its wall is stretched
and a signal is sent to the brain which gives the child the urge
to have a bowel movement. If the child sits at the toilet, relaxes
the sphincter (the muscle that controls the opening of the anus),
increases the abdominal pressure by holding his breath and pushing
down (this is called Valsalva manoeuvre), he will push the stool
out of the rectum. This explanation sounds quite complex for
something that is universal for all human beings, but understanding
this can help to explain what happens in constipation.
For a young infant, the time it takes for milk to enter the stomach
until it is eliminated as stool is only a few hours. Therefore,
the stool in babies are often very soft and runny. There can be
as many as 12 stools a day in breast-feeding infants to as little
as one to two stools in those fed with infant formula. However,
by two to three months of age, some breast-feeding infants may not
pass stool more often than once a week. This can be perfectly
normal and doesn't indicate constipation, as long as the stool is
still soft and the child is otherwise healthy.
As a child gets older, the transit time for food going through the
intestines gets longer. In a two year old child, this can take 16
hours. The transit time for a ten-year-old child is about 24 hours.
The longer the transit time, the more water is absorbed by the
large intestines, and the stool would become firmer in consistency.
Older children who have no constipation often would have three or
more bowel movements a week. They may skip a day here and there,
and their stool is usually soft to firm, and not large in diameter.
There should be no pain on defecation, and each time there should
be a fairly good amount of stool.
On the contrary, a constipated child can have one or more bowel
movements a day (although most of the time it is more infrequent).
However, each bowel movement usually has a small quantity of hard
stool. What is happening is that the child cannot empty the stool
collected inside the rectum. Because the stool is hard, these
children will only allow a small amount of stool to pass at each
movement. As long as the pressure in the rectum is relieved, they
would rather withhold the stool instead of tolerating the pain
associated with defecation.
There are many causes of constipation. Sometimes it is not easy
to find out what actually happened in a particular child. Constipation
tends to happen when there is a change in the child's life. An
infant who is breast-fed from birth can become constipated when he
is started on cow's milk formula or homogenized milk. Changing
from pureed food to table food can cause constipation in some
children. Starting daycare and full-day school can be stressful
enough for some to develop problem. However, the most common cause,
as in your son's situation, is toilet-training.
Why toilet-training causes constipation is not completely understood.
It is possible that many children are not matured enough or
emotionally ready when parents started the process. When they are
still in diapers, and if the stool is fairly soft, it doesn't take
much effort for them to relax the sphincter and push the stool out.
It is quite possible that with toilet-training, the anxiety causes
the child to tighten the sphincter instead of relaxing it. Once
the stool is held in the rectum, water is absorbed and the stool
becomes more firm. When the child gets the signal to pass the
stool, it would require much more straining than before. The longer
the stool stays in the rectum, the more water is removed, the harder
it gets. Hard stool will lead to pain on defecation and further
withholding of stool, setting up a vicious cycle that finally ends
up in constipation.
Once constipation starts, the stool not only gets harder, it also
gets larger in size and diameter, over-stretching the wall of the
rectum and colon above. Stretching the wall reduces the contracting
power of the muscle in the intestine, which is important in pushing
the stool forward towards the rectum. This is similar to blowing
a balloon: once the balloon is stretched, it doesn't get back to
its original size. This is why treatment of constipation requires
a long maintenance phase so that the colon has a chance to recover
its original calibre and muscle tone.
The first step in the treatment of constipation is to clean out
the bowel and eliminate all the stool that has been collected.
This often takes several days, and can be done either at home or
in the hospital. It may involve enemas (instilling a liquid into
the rectum) or taking a laxative by mouth. Sometimes, if the
constipation is very severe, the doctor may have to pass a tube
through the nose into the stomach in order to instil a medicine
that can break up the very hard and constipated stool.
Once the evacuation process is finished, the child needs a maintenance
program that prevents constipation from recurring. It has taken
months or years for constipation to establish, it will take a long
time for the intestine to regain the muscle strength. The child
needs to have one or more soft bowel movements a day, everyday.
There are many things that can help. At the beginning, it may be
wise to reduce dairy products like cow's milk and cheese. It has
been recognized that the high fat content in dairy products can
reduce gut motility and promote constipation. Once the constipation
is well under control, dairy products can be slowly increased.
Some sugars that cannot be digested by our intestines are very
helpful, because they can reduce water absorption by the colon and
prevent the stool from getting too dry and hard. These sugars
include fructose and sorbitol that are found in prune juice.
Lactulose, a sweet liquid made with two molecules of lactose that
our body cannot digest, is available in pharmacy and can be very
effective for those children who won't take prunes or prune juice.
Extra fibre is also very important in the maintenance phase of
treatment. The best source of fibre is in fruits and vegetables.
Many children need extra encouragement when it comes to this food
group, but parents can set a good example at home. The benefits
of fruits and vegetables extend beyond the bowel. There are lots
of excellent nutrients and vitamins. Research has shown that they
can also prevent certain cancers.
Children with constipation can benefit from extra fibre available
in whole wheat cereal and bread, as well as supplements like
Metamucil or fibre pills. Some children are more receptive of
pills instead of drinking a glass of Metamucil. Parents have to
try different things to find out which is going to work.
Most of the time, mild laxatives are necessary at least initially
to maintain regular bowel movements. They do not cause 'lazy
bowel,' contrary to many people's belief. Mild laxatives allow
the child to have consistent daily bowel movement that is fairly
soft. This will prevent withholding of stool in the rectum and
lower part of large colon, and allow it to return to its normal
calibre and muscle tone. With time, laxatives can be slowly reduced
and stopped, but this likely will take many months.
Management of constipation requires lots of patience from the
parents and physicians. Most of the time, failure of treatment is
because of inadequate evacuation of constipated stool, inadequate
medicine during the maintenance phase, or stopping the medicine
too quickly. It is important to recognize that constipation is a
chronic problem, it has been going on usually longer than the
parents recognize, and it will take a long time to correct.
In addition to medicine, it is also important to work on a regular
bowel habit. The best time to sit a child at the toilet is right
after a meal, when the intestines are most active. It is important
to provide a calm environment, and encourage the child to relax
the anus and increase the abdominal pressure. With adequate medicine
and regular toilet time, the constipation problem can be overcome.
I should mention here that it is important to provide a footstool
at the toilet for your son so that his feet can rest on firm ground
in order to apply the abdominal pressure effectively. If he is
afraid of the large hole in the toilet seat, you can give him a
small potty, or place a toilet seat insert so that he doesn't have
to worry about falling into the toilet. Using stars and stickers
on the calendar to chart successful bowel movements can give you
child the additional encouragement.
Rarely, children with constipation require counselling by trained
psychologists. If all the treatment plans that I have discussed
here are not effective, further assessment by a doctor specialized
in gastroenterology would be necessary.
I hope you can work with your doctor to help your son and prevent
him from a life-long misery of constipation.
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