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Constipation is a common problem in children and is often associated with
maladaptive behavior triggered by a painful or otherwise unpleasant defecation.
There is no universally accepted definition of constipation, although
the term is generally describes infrequent or painful bowel movement
due to stool that is too large or hard to pass.1,2 The
Rome Committee, consisting of a group of pediatric gastroenterologist
from Europe and North America, defined constipation as 2 or more
of the following symptoms in a child with a developmental age of
at least 4 years: 2 or fewer defecations in the toilet per week,
at least 1 episode of fecal incontinence per week, history of retentive
posturing or excessive volitional stool retention, history of painful
or hard bowel movements, presence of a large fecal mass in the rectum,
and history of large-diameter stools that may obstruct the toilet.3,4
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The incidence of constipation in 5 to 21 year olds is estimated
to be 3.9 per 1000 person-years. The prevalence of constipation
in children ranges from 0.7% to 29.6% (median
8.9%).5,6 About 3% of children
experience constipation in the first year of life and about 10% in
the second year of life.7 Constipation accounts
for almost 3% of general pediatric outpatient clinic visits
and 10% to 25% of visits to a pediatric gastroenterology
clinic. Most cases of functional constipation present between ages
2 and 4 years. The incidence of constipation in children younger
than 13 years is similar between genders, but in older children,
girls seek medical help more often than boys. In school-aged children,
fecal soiling is 3 times more common in boys than in girls. The
incidence increases when a parent, sibling, or twin has constipation.
Monozygotic twins are 4 times more likely than dizygotic twins to
have constipation.
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A normal pattern of defecation requires the removal of water
from the liquid chyme that enters the cecum and propulsion of soft,
formed colonic contents through the colon to the rectum, which stores
stool until defecation. Sensation of the need to pass stool by rectal
smooth muscle contraction and reflexive partial inhibition of the
internal anal sphincter allows stool to impinge on the sensory area
of the mucosa of the upper anal canal. To achieve continence, the
child must be able to perceive this urge to defecate, and then,
if in the appropriate setting, the child must plan to find a lavatory
depending on the urgency. This is not an innate ability but requires learning
in a supportive environment. If the child has learned that stooling
is painful, or if appropriate access to a socially acceptable location
for passing stool is unavailable, the child withholds the stool
by external anal sphincter and pelvic floor contraction. Once the
child decides to defecate, the puborectalis muscle is relaxed, allowing
the pelvic floor to descend and straighten the anorectal angle from ...