Download Defaecation disorders in children

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REVIEW
Defaecation disorders in children
Fae Farrer, BPharm
Abstract
Constipation is a condition that is difficult to define. It is a common problem occurring in adults and
children. Numerous factors can cause constipation in children, including a change in diet and emotional
causes. Children with constipation may, however, present with unusual symptoms. Simple advice about
sufficient dietary fibre and fluid intake may be all that is needed. Referral to the doctor would be best
if these measures are unsuccessful. Diagnosis and treatment of persistent constipation are important to
prevent possible complications such as anal fissure, stool withholding and encopresis.
Introduction
Constipation is a common problem occurring in both adults
and children.1,2,3 Estimates of the prevalence of constipation in
children vary between 1 and 30%.4 The variance in these figures
may be due to differences in the definition and interpretation of
the term ‘constipation’.
Although constipation is common and varies in presentation and
severity, it should not be ignored, as a small percentage of children
may have organic causes for constipation. Children with functional
constipation will also benefit from timely treatment.4 Constipation
accounts for between 3 to 5% of all visits to paediatricians.1,4
Physiology of elimination
Faecal matter moves through the colon by contractions that
occur several times a day. The motility of the colon is increased
after a meal (the gastrocolic reflex) and assists in propelling
stool along the colon to the rectum.1
Defaecation is a reflex brought about by the stimulation of receptors in the rectal mucosa. The rectum is empty until peristalsis moves faecal matter from the colon to the rectum.5 Distension of the rectum produces the desire to defaecate. Reflex
relaxation of the internal sphincters of the anus is initiated. If
defaecation is desired, voluntary straining efforts and relaxation
of the external anal sphincter allows elimination of faeces.5 If defaecation is not desired, voluntary inhibition of the receptors and
contraction of the external anal sphincters prevents faecal loss.1.5
•• After four years of age, the average is one to two bowel
movements per day. 2,4
Constipation presents as hard, dry, pellet-like stools that are difficult to pass and cause pain on defaecation. A child who normally
has a bowel movement every day may be considered constipated
if the child has not had a bowel movement in two days. However,
some children may, under normal circumstances, only have a
bowel movement every two days. The important difference is
therefore the presence of hard stools which are difficult to pass
and are less frequent than usual for that particular patient.2
Infants and young children may develop certain habits or postures when they feel the urge to have a bowel movement2:
•• Infants may arch their backs and cry
•• Toddlers may rock, stand on tiptoes, wriggle or squat
Sometimes it may appear that the child wants to have a bowel
movement, but the child tries to prevent passing a stool because they are frightened of the toilet or of the pain they might
experience whilst having a bowel movement.2
Constipation
Constipation is not a disease, but rather a symptom of another underlying problem. Often the term constipation reflects a person’s
view of what constitutes ‘normal’ in terms of bowel movements.
Normal patterns of stooling
The definition of constipation encompasses terms such as infrequent or difficult bowel movements, painful defaecation, passage
of hard stools and a sensation of incomplete evacuation of stool.1
Normal stooling habits depend on the age of the child:
•• During the first week of life, infants pass an average of four
soft or liquid stools a day.2,4
•• During the first three months, breastfed infants pass an
average of three soft stools per day, varying from one per
day to one after each feed. Formula-fed infants pass an
average of two stools per day.2,4
•• By the age of two years most children have one to two
bowel movements per day. 2,4
The North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) defines constipation in children
as a delay or difficulty in defaecation, present for two or more
weeks and sufficient to cause significant distress to the patient.1
Childhood constipation has been defined as two or more of the
following occurring over the preceding eight weeks1:
•• Frequency of bowel movements less than three per week
•• More than one episode of faecal incontinence per week
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•• Large stools in the rectum or palpable on abdominal
examination
•• Passing of stools so large that they obstruct the toilet
•• Retentive posturing and withholding behaviour
•• Painful defaecation
in passing a bowel movement precipitates the desire to withhold
stool.1 If a child has delayed a bowel movement for any reason,
the next stool passed may be painful and lead to withholding
behaviour. Pain may also be caused by an anal fissure (tear in the
anus) after passing a particularly hard or large stool. 2
Causes of constipation in children
Constipation is fairly common at three stages in a child’s life2:
•• After starting solid or semi-solid food from a previously allmilk diet
•• During toilet training and
•• When the child starts school
Major causes of constipation in children may be broken down
to two categories: functional and organic.
Functional constipation is a broad term for persistent, difficult,
infrequent or seemingly incomplete defaecation without evidence of a primary anatomic or biochemical cause.4,6 Functional constipation accounts for the majority of constipation-related
symptoms in children.
Organic causes for constipation include4:
•• Anatomic malformations
•• Metabolic and gastrointestinal causes e.g. hypothyroidism,
cystic fibrosis, coeliac disease
•• Neuropathic conditions e.g. spinal cord abnormalities or trauma
•• Intestinal nerve and muscle disorders e.g. Hirschsprung’s
disease
•• Abnormal abdominal musculature e.g. Down’s syndrome
•• Connective tissue disorders
•• Certain medications e.g. antacids, opiates or phenobarbital
•• Other causes include cow’s milk protein intolerance and
vitamin D intoxication
•• Organic causes are responsible for fewer than 5% of cases
of constipation in children.4
A careful history and physical examination will identify any problems that may signal possible organic causes of constipation.
The patient history should include obtaining information on:
•• Age at which symptoms started
•• Duration of symptoms
•• Frequency of bowel movements
•• Diet
•• Withholding behaviour
•• Faecal incontinence
•• Presence of associated symptoms such as abdominal pain
and/or distension, vomiting, weight loss
•• Family history of constipation, thyroid disease, coeliac disease, Hirschsprung’s disease or cystic fibrosis.1
Firmer stools and subsequent painful defaecation may result
from a change in diet, such as the change from breast milk to
cow’s milk formula or soy milk formula. Changes in bowel movements may also be expected when the diet changes from all liquid to some liquid and some solid food. Firmer stools may result
from a diet lacking in dietary fibre or from inadequate non-milk
fluid intake.2,3,4 Cow milk protein allergy or intolerance may also
lead to hard stools, anal fissures and painful bowel movements.1
Toilet training in a toddler not yet ready for this developmental step
may cause more problems than anticipated. A child not yet interested
in using the toilet may try to avoid the bathroom, leading to faecal
withholding and eventual passage of hard, dry stools with discomfort, which in turn leads to unpleasant associations with the toilet.1,2
In older children unpleasant facilities at school, withholding for
convenience when wanting to play or anal pain arising from infection or sexual abuse may increase the tendency to withhold
stool leading to painful and unpleasant defaecation.1,2
A study of children presenting to a paediatric gastroenterologist
with difficult defaecation showed that4:
•• Of the younger children, 86% presented with pain, 71%
with impaction and 97% with severe withholding. The
younger children had painful defaecation for an average of
14 ± 9 months before visiting the doctor.
•• Of the older children, 85% presented with faecal soiling, 57% with pain, 73% with faecal impaction and 96%
exhibited withholding behaviour. Sixty three percent of the
children presenting with faecal soiling had a history of painful defaecation beginning before three years of age.
The physical examination should include the whole body so as not
to misdiagnose constipation as a complication of a systemic illness.
Faecal masses may be palpable in the lower abdomen. Anal examination may reveal anatomic abnormalities or anal fissure.1
Faecal withholding begins as a result of pain and becomes a
recurrent problem.1 Painful defaecation often precedes chronic
faecal impaction and faecal soiling.4 Early effective intervention and treatment of painful defaecation may decrease the
incidence of chronic faecal impaction and faecal soiling. 4
Aetiology of functional constipation
Encopresis
Approximately 95% of children with constipation have no obvious
anatomic, biochemical or physiological abnormalities. Many of
these children have functional constipation resulting from dietary
deficiencies, a change in diet or emotional problems leading to
intentional withholding of stool. Often an unpleasant experience
When a child withholds a bowel movement, stool accumulates
in the rectum and becomes hard. With chronic rectal distension
due to stool accumulation, the anal sphincter dilates, and when
the external anal sphincter relaxes semisolid stool leaks onto
the perianal skin and clothing.4
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Faecal incontinence (also termed encopresis or soiling) refers to the
repetitive (voluntary or involuntary) passage of stool in inappropriate
places by children four years of age or older, at which time a child
might be expected to be able to exercise bowel control.6
Encopresis is usually associated with chronic constipation and faecal retention, but may occur without faecal retention. Non-retentive
faecal incontinence describes faecal incontinence occurring in the
absence of constipation or organic disease. Children may have full
bowel movements in their clothing instead of just soiling.6
Encopresis due to functional constipation is alleviated by treating
the constipation. Treatment of non-retentive faecal incontinence
focuses on behaviour modification, diagnosis of psychosocial
problems and support.6 Laxatives are not helpful in these cases.
Treatment of functional constipation
Patients with organic causes for constipation must be referred
and treated appropriately. Functional constipation is treated
slightly differently in infants compared to children.
Infants – When constipation occurs in neonates and young infants it may be due to organic disease such as Hirschsprung’s
disease or cystic fibrosis.6 The infant must be carefully evaluated so that an accurate assessment may be made.
Older infants with functional constipation often respond to nondigestible osmotically active carbohydrates such as sorbitolcontaining fruit juices e.g. apple, prune or pear juice.3,6 If this
treatment is unsuccessful, osmotic laxatives such as lactulose,
and/or glycerine suppositories may be used. Mineral oil is not
recommended in infants due to potential risks of pneumonia if
regurgitated and breathed into the lungs.6 Infants with faecal
impaction may need suppositories e.g. glycerin suppositories
or rectal stimulation with a lubricated rectal thermometer to
remove hardened dried stool. These therapies should not be
used regularly as infants may become dependent on rectal
stimulation to achieve a bowel movement.3
Children with recent onset constipation should be treated with
dietary changes such as increased fibre and fluid intake. The
recommended normal intake of dietary fibre is the patient’s age
in years plus 5 grams per day.1 Small children often consume
cow’s milk to the detriment of other fluids and foods that may
promote soft stools (e.g. water, fruits and vegetables). Useful fruits
and vegetables include apricots, sweet potatoes, pears, prunes,
peaches, plums, beans, peas, broccoli and spinach.2 Increased
non-milk fluid intake may promote softer stools, decreasing pain
on defaecation. 3
In children with functional constipation caused by intentional
faecal withholding a three-step approach is required. The goal of
therapy is one soft stool per day.6
1. The first step in the treatment plan is education. The patient
(and parents) need to understand the cycle of retaining faecal
matter, which then becomes dry and hard, leading to painful
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evacuation.1 It should be explained that when a large amount
of stool is retained in the rectum, the sphincters may lose
tone allowing leakage of small amount of fresh stool.1
2. The second step is the removal of any faecal impaction by
using a laxative. Once withholding behaviour has started,
it can only be reversed by making the passage of stool
pain-free.3 The child’s doctor should be consulted before
any enema or “clean out” regimen is started.2
3. Behaviour modifications are the third step in combating functional constipation and aim to establish a regular pattern of defaecation and to ensure healthy bowel habits.1 Children should
be encouraged to sit on the toilet at regular times (typically
after a meal). Laxatives may be required to ensure soft stools
at first, and should be gradually weaned when a regular bowel
habit is established and the child no longer withholds stool.1
If constipation occurs due to problems during the process of toilet
training, this process should be temporarily stopped. The child
should be encouraged to use the toilet when they feel the urge
to, and given positive reinforcement for doing so.2 Toddlers using
adult-sized toilets should be supplied with foot support such as
a step or stool. Some children feel insecure if their feet are not
touching something, while most require the foot support for leverage when pushing and bearing down during a bowel movement.2,3
Children starting at school may be reluctant to use a toilet
at school, especially when the facilities are communal and
“public”. Other child-ren may be too busy to go to the toilet and
suppress the urge to stool.2 The child’s teacher should be consulted to find a solution, such as the child using the bathroom
at a time other than “toilet time”.
During acute episodes of constipation, dietary changes may be
used while precipitating causes are identified and treated.3 All
cases of chronic or recurrent constipation should be monitored
to prevent recurrence. Treatment regimens may require adjustment to ensure progress.6
Conclusion
Most children with constipation do not have an underlying medical
problem and so do not require drastic medical or surgical intervention. Children are susceptible to constipation at various times during
childhood. Appropriate and timely intervention can prevent complications such as stool withholding, anal fissures, chronic constipation and encopresis.3 Parents should be aware of possible trouble
times such as the transition to solid foods, toilet training and school
entry, and should know of suitable solutions to the problem.r
References
1. Croffie JM. Constipation in Children. Indian Journal of Pediatrics 2006;
73(8): 697-701. Accessed 24 March 2010
2. Ferry GD. Patient Information: Constipation in infants and children. www.
uptodate.com Accessed 24 March 2010
3. Ferry GD. Prevention and treatment of acute constipation in infants and
children. www.uptodate.com Accessed 24 March 2020
4. Ferry GD. Constipation in children: Etiology and diagnosis. www.uptodate.
com Accessed 24 March 2010
5. Thibodeau GA, Patton KT. Anatomy and Physiology. 3rd edition.1996.
Mosby-Year Book, Inc.
6. Ferry GD. Treatment of chronic functional constipation and fecal incontinence in infants and children. www.uptodate.com Accessed 24 March 2010
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