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ENURESIS - a patient's guide
Dr Max Morris - Paediatrician
What is it?
Enuresis means bedwetting and is a common problem in childhood.
The incidence is between 12-15 percent for five and six
year olds, 5 percent for 10 year olds and 1 percent for
15 year olds.
The male to female ratio is equal in five year olds but
enuresis is more common in boys by the age of 10, with a
male to female ratio of 1.5:1 at 10 years.
There may be a lower incidence of enuresis in Chinese
children. One Hong Kong study found 3.5 percent of five
year olds suffered from it. Otherwise, the incidence is
similar in various studies around the world.
Children with enuresis fall into two categories:
a) Large nocturnal urine output with normal bladder volume.
b) Normal or large nocturnal urine output with small functional
bladder volume.
Less than five percent of cases have a structural abnormality
of the urinary tract. These cases may be suspected by daytime
wetting, poor urinary stream and the presence of a urinary
tract infection.
Enuresis can be associated with chronic constipation and
occasionally linked with upper airway obstruction and sleep
apnoea.
There is often a family history of the problem. About
60 percent of affected children have an affected parent.
Recent studies are searching for possible genes which may
cause or predispose children to the condition. There is
some evidence of a link between the condition and three
genes on chromosome 13q, 12q, and 22q (q means long arm
of that chromosome).
Although strong genetic predisposition is evident, this
probably explains about 70 percent of the risk. Other factors
are still uncertain.
How is enuresis diagnosed?
Establish whether the child has abnormal daytime voiding
(urinating) pattern. This includes establishing frequency,
urgency, urinary stream, daytime wetting, and symptoms of
urinary tract infection currently or in the past.
The doctor will examine the child's abdomen for evidence
of constipation or enlarged bladder after voiding. They
will also examine blood pressure, spine, lower limbs, external
genitalia - foreskin and urinary meatus (hole at tip of
penis) in boys, and posterior labial fusion in girls.
Samples of the child's urine will be sent to a laboratory
for testing.
An ultrasound will be ordered only if there are clinical
features in addition to nocturnal enuresis such as daytime
wetting and urinary tract infections.
There is currently no genetic or other predictive test
to establish whether a particular child is predisposed to
enuresis.
Diagnosis is only made in children aged five years or
older. Children below this age fall within normal variations
of development.
What can be done?
Enuresis can resolve spontaneously. The spontaneous resolution
rate for enuresis is 15 percent per annum. However, there
is no reliable way of predicting whether an individual child
will become dry in the next 12 months.
Behavioural method
The enuresis alarm (bed buzzer) method has an established
efficacy of about 70-80 percent when used correctly.
This method requires a reliable alarm system with a low
'false alarm' rate. It is usually best used in a child mature
enough to want to become dry and who can cooperate with
the treatment method - usually 7 years or older.
There are a few studies which have shown some 5-6 year
old children can become dry with the enuresis alarm method.
The relapse rate in children successfully treated with
the enuresis alarm is low, about 10-15 percent.
The successful application of the enuresis alarm method
takes several weeks, often 6-8 weeks to be effective.
Medication
Desmopressin is an analogue of antidiuretic hormone. It
has the effect of greatly reducing the urine production
rate, over a period of 8-12 hours. It is administered by
a nasal spray. It is about 75 percent effective. However,
it is effective only on the night it is administered.
There is no convincing evidence that desmopressin has
any favourable effect on the natural history of the condition,
i.e. it does not increase the recovery rate above 15 percent
per annum.
It is not recommended for long-term use. It is very helpful
for short-term use for special occasions like school camps,
sleep overs, etc.
It is a very safe treatment when used in accordance with
the advised precautions - the most important being not to
have further drinks until the next morning after the medication
has been administered.
A small group of children with enuresis may be helped
by the use of oxybutynin, an anticholinergic bladder muscle
relaxant, especially those children who have a small functional
bladder capacity. These children have daytime urgency and
frequency, but even if the medication improves their daytime
symptoms, it may not stop their bedwetting.
An earlier treatment for enuresis was the use of imipramine,
which also has a mild anticholinergic effect (allows the
bladder to fill to a bigger volume) and may also enable
the child to wake more easily when the bladder is full.
Imipramine is not often used for the treatment of enuresis
now, it can be regarded as a second-line therapy.
Other methods of management have no proven efficacy,
these include:
Fluid restriction before bed
Parent waking the child during the night for toileting
Punishment
Encouragement e.g. star charts
Prognosis
Most children do eventually cease to have bedwetting,
but there is a small incidence (less than 1 percent) in
the adult population.
There are no convincing studies showing psychological
or behavioural disturbances have led to enuresis, but persistent
enuresis can lead to an unhappy, withdrawn child. For this
reason many authorities recommend intervention to treat
the condition and reduce this risk, but there are few if
any prospective studies which have proven this benefit.
Seeking help:
Don't hesitate to discuss possible treatments with your
doctor if needed.
The New Zealand Continence Association has a freephone
number for people to call for information and support. Ph
0800 650 659.
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