Paediatrics: Enuresis

Enuresis

Enuresis is the involuntary emptying of the bladder. Although children may ‘wet’ themselves by day or night, the term enuresis is applied to nocturnal enuresis. When it occurs during the day, while awake, it is known as diur-nal enuresis. Nocturnal enuresis is more common.

In order to learn bladder control the young child needs to overcome the infant automatic pattern of voiding. For the young child, conscious awareness of fullness and the ability to postpone voiding by suppressing the urge to void are not perfect. This response is first learned for day-time control. Eventually, bladder control becomes automatic and does not require a conscious act. Night-time bladder control requires that the brain, during sleep, suppress the automatic emptying reflex. Learning blad-der control at night occurs gradually, and in some children and families takes much longer than average.

Girls achieve bladder control earlier than boys. Enuresis is defined as the continued wetting in girls beyond the age of 5yrs, and in boys beyond the age of 6yrs.

Enuresis may be primary, with children not having established an appro-priate period of adequate bladder control in early childhood, or secondary occurring after a period of established bladder control.

Primary enuresis

•   A strong family history.

•   Boys more commonly than girls (ratio 2:1).

•   15% of 5-yr-olds, 5% of 10-yr-olds, and 1% of 16-yr-olds have not established total bladder control and will wet the bed once a week or more.

•   Majority of cases have no underlying organic cause and it is thought to be due to delayed maturation of bladder control mechanisms.

Secondary enuresis

Needs careful history and investigations because of probable organic cause.

Possible organic causes of secondary enuresis

•   Renal tract: urinary tract infection

•   Neurological: spina bifida

•   Endocrine: diabetes mellitus, diabetes insipidus

•   Behavioural problems

•   Abuse

Daytime wetting is usually caused by bladder detrusor instability.

Treatment

Primary (nocturnal) enuresis

• Encourage regular drinks (water), but restrict in last hour before bed.

• Give drinking/voiding chart.

If primary nocturnal enuresis is associated with arousal from sleep or disturbance, then an enuresis alarm should be considered. This requires careful discussion with families. Compliance is often an issue and the fam-ily and child need to be motivated. If enuresis associated with a small bladder, ‘bladder training’ exercises is first-line approach. Also consider using bladder-stabilizing drugs, e.g. oxybutynin. If nocturnal enuresis and urine output exceeds bladder capacity consider using desmopressin (anti-diuretic hormone) and limit fluid intake 1hr before bedtime.

If the problem is resistant to the above treatments, other pathologies need to be considered:

• Urinary outflow obstruction in boys.

• Chronic constipation.

• Neurodevelopmental problems.

• Psychological problems.