In this lecture, we’ll be talking about
constipation and Hirschsprung’s disease.
So, what is constipation?
It seems inherently obvious but it
does vary in diagnosis based on age.
Little children stool more
frequently than older children.
So, constipation is a delay or
a difficulty in defecation.
Normal infants will pass meconium
within about 48 hours of birth.
A delay there may herald an
inherent problem with defecation.
Among breastfed infants after
that first initial period,
typically, infants will be stooling
between two and four times a day
up until around the age
of three months of age.
Formula fed infants stool
much less frequently
and may even go once
every two or three days.
By the time children are
three to four years of age,
they are generally
stooling about once a day,
which is typical for adults too although
there is of course some variation.
There are some risk factors for
constipation that we should be aware of.
First, dietary changes.
Certainly, people who have a low fiber diet
are at increased risk for constipation.
As children grow older, sometimes
stooling becomes a problem for them.
They have anticipatory
fear of a painful stool
or they decide they’re too
busy with other activities
and they don’t want to have
to go to the bathroom.
This delaying as a behavior
can result in constipation.
Also, sometimes children
have organic changes
in their body that
result in constipation.
So if you see a patient where
you suspect constipation,
again, taking a good
history is key.
Understand the birth history
related to meconium.
A delay in that meconium may herald a
problem such as Hirschsprung’s disease,
which we’ll talk about
a little bit later on.
Understand the frequency, the
consistency and the size of the stools.
Large bulky stool is consistent with
constipation, decreased frequency.
And also, hard ball or very hard stools
that are painful to pass are classic,
and so pain with bowel movements is
also a heralding sign of constipation.
Patients may have fever,
weight loss, and vomiting,
but those are unusual for constipation and
may mean that something else is going on.
Dietary habits are key.
It’s important to
understand whether children
are having a low fiber
or a high fiber diet.
is also important.
There are some medications that can
delay the rate at which we stool.
Delve into the toileting
behavior behind children.
Sometimes parents, while teaching
their children to use the toilet,
engage in behavior that
is not supportive.
This can make children fearful
of the toileting experience,
which can result
And also, children with frequent
urinary tract infections
often have constipation as the cause.
Remember, a large ball of hard
stool in the rectal vault
can impinge the outlet
of that bladder.
And so children who can’t empty
their bladder all the way
are actually at increased risk for
urinary tract infections frequently.
In one study, a large percentage of
children with vesicoureteral reflux
which puts kids at risk for urinary tract
infection actually also had constipation.
Constipation is a big problem
in children with UTI.
So on exam,
we’ll look at these children and we’ll
try and figure out what’s going on.
The abdominal exam is important because
you can often actually palpate stool
in the left lower quadrant or
throughout the abdomen in severe cases.
Palpating stool, these masses are soft
and you can almost form them with
your hand as you’re pushing in.
They are not hard masses but you
definitely will feel a very full abdomen.
An anal and rectal exam can be helpful.
We don’t usually do this in little children
when there’s a clear
diagnosis of constipation,
but if we’re unclear, an exam is important.
You can position them appropriately
and inspect for anal wink,
look for distention
and certainly, look for things like fissures
or hemorrhoids which are associated with it,
or frank occult blood.
If you inspect the rectal area and then
look superior just above the buttocks,
you can find often hair tufts,
dimples, or other problems
that may be a sign of a problem with the
enervation of the lower intestinal tract.
Patients with spina bifida, for
example, may also have constipation.
Also, understand the CNS disease and
do a full exam of the CNS system,
checking for things like
which will be decreased in patients
with lower enervation problems,
as well as lower extremity
tone, strength, and reflexes.
Those are all signs the child
may have a neurologic problem,
which is contributing to the constipation.
So, looking at the
pathophysiology of constipation,
basically, when we stool, there is both
voluntary and involuntary muscle contractions
that are involved in both controlling
continence and active stooling.
Painful bowel movements may result
in a child who withholds stool.
You can imagine a cycle where a
child happens to be constipated
because they had a low fiber
meal for several days in a row.
And then they had an experience when
they stooled, and it was painful
because that hard ball of
stool stretched the rectum
and the descending colon
in an uncomfortable way.
As they then continue to refuse to
stool because of anticipation of pain,
the rectal sensation gradually decreases,
and there is gradual dilatation
of that rectal vault.
Additionally, you now need more stool
to cause the urge to defecate.
This cyclical problem results in
worse and worse constipation.
With chronic retention, the
internal sphincter dilates
and even when the external
This causes liquid stool leakage around the
hard ball, which we might call encopresis.
Children with this might get skid marks
or brown streaks in their underwear,
which are not fully formed stools but
rather leakage around the stool.