Introduction

Nocturnal enuresis (bedwetting): involuntary wetting during sleep without any inherent suggestion of frequency of bedwetting or pathophysiology.

Definitions¹

• Primary nocturnal enuresis. This is the recurrent involuntary passage of urine during sleep by a child aged 5 years or older, who has never achieved consistent night-time dryness. This may further be subdivided into children who have enuresis only at night and those who also have daytime symptoms (urgency, frequency, or daytime wetting).
• Secondary nocturnal enuresis. This is is the involuntary passage of urine during sleep by a child who has previously been dry for at least 6 months.

Primary enuresis most often represents developmental delay which resolves in time. In secondary enuresis the patient regresses after a period of continence, which requires the exclusion of underlying pathology, e.g. a urinary infection.

Three aetiological factors are commonly involved: a disorder of sleep arousal, a low nocturnal bladder capacity and nocturnal polyuria. Constipation may be an additional aggravating condition.²

Epidemiology

At age 4½, 30% of children still wet the bed, 21% infrequently (less than 2 times per week) and 8% of these more frequently.^3,4 Bedwetting rate falls to 9.5% at just over 9½ years (115 months).³
Children with more frequent wet nights are more likely to have a persistent problem and benefit from early identification and investigation.

A large cohort study found that 2.6% of 7 year-olds still wet the bed more than twice a week.⁵ This represented 3.3% of boys and 2.3% of girls. A total of 15.5% were not totally reliably dry and occasionally still wet the bed.

Risk factors

There are a number of factors that predispose to persistent nocturnal enuresis.

• There is a genetic predisposition.⁶ As an illustration, it is said that the risk of nocturnal enuresis is 15% if neither parent was affected, 40% if one parent was affected and 75% if both had the condition.⁷ One study found that patients with a family history of primary nocturnal enuresis had a higher incidence of small bladder capacity or outflow obstruction than controls.⁶
• 23% of nocturnal enuresis is associated with encopresis and daytime incontinence.⁸
• Enuresis is to be expected as a manifestation of developmental delay, in those with global developmental delay, with or without an associated syndrome such as Down's syndrome. Even without gross developmental delay, there is more likely to be persistent bedwetting in children with delayed developmental milestones, premature delivery or behavioural disorders such as hyperactivity or inattention deficits.^9,10
• There may be neurological problems such as spina bifida or cerebral palsy. Those with physical problems are more likely to have daytime enuresis or trouble with encopresis. Physical problems are a rare cause of nocturnal enuresis per se.
• Constipation can cause bladder problems.¹¹ In an American series, those with severe constipation (even causing encopresis), benefited from treatment of their constipation and this treatment cured about two thirds of their nocturnal enuresis.¹² There was also a high rate of urinary tract infection (UTI), affecting 3% of boys and 33% of girls.
• Other risk factors include disturbed sleep,¹³ mother aged less than 20 at the time of the child's birth, mother smoking at least 10 cigarettes a day at home, and not being first born.¹⁴ In that survey, only 50% of parents had consulted a doctor about enuresis. Afro-Caribbean children seem to have a slightly higher incidence than white children and only 35% of the families had consulted a doctor. These risk factors have not changed in 45 years.
• Airways obstruction with snoring increases risk.
• Drinks containing methylxanthines (e.g. caffeine and theophylline found in 'high-energy' drinks) can aggravate the situation by their diuretic action. These include tea, coffee, cola and chocolate.
• Stresses in the child's life, such as an admission to hospital with separation from the mother, or bullying, are more likely to cause secondary enuresis. The older the child, the more likely it is that psychological problems are the result of enuresis and not the cause.

Assessment

To decide on appropriate investigations and treatment it is important to identify:¹

• Whether there are any daytime symptoms (abnormal frequency of urination (either too frequent (more than 7 times/day) or infrequent (less than 4 times/day)), urgency, daytime wetting, difficulty (straining) with poor stream, or pain on urination? Do symptoms occur only in some situations, e.g is there avoidance of toilets at school?
• Whether the child has previously been dry at night without assistance for 6 months (i.e. this is secondary enuresis)? If so, ask about any medical, physical or environmental, social or emotional causes or triggers for the change (e.g. bereavement, bullying, parental separation, etc.).⁴

Also ask:

• How many times a night and how many nights a week?
• Do there seem to be large quantities of urine in the bed?
• Is there any pattern - what time does bedwetting occur?
• Does the child wake after wetting the bed?
• What is the daytime pattern of toilet use?
• Is there also constipation or soiling?

Consider whether the child has:

• Developmental, attention or learning difficulties?
• Behavioural or emotional problems?
• Family problems or a vulnerable child/young person/family?
• Could this be maltreatment (especially if bedwetting is reported as deliberate or the child is being punished for bedwetting)?
• Could this be diabetes mellitus?

A diary of fluid intake, symptoms, bedwetting and toileting patterns may help clarify the history in some cases.

• Passing large volume in the first few hours is typical of bedwetting only.
• Variable volumes, more than once a night or every night - possible overactive bladder, or other physical disease.

Investigations

Urinalysis is not recommended unless bedwetting is of recent origin, there are daytime symptoms, or symptoms are suggestive of possible infection or diabetes mellitus.⁴

Investigate (and treat) daytime symptoms before addressing enuresis, e.g. symptoms suggestive of diabetes, UTIs or constipation.

Management

Children without daytime symptoms

If aged under 5, reassure parents that this usually resolves over time without treatment. Some things may help:

• Ensure adequate but not excessive fluid intake during the day (1,000-1,400 ml per day in a child aged 5), healthy diet and avoid caffeine-based drinks before bed.
• Encourage the child to empty their bladder before bed, and ensure there is access to the toilet at night. A potty by the bed may help.
• If the child has been dry during the day for >6 months, a trial without nappies can be tried (waterproofing of the mattress will be required). Trial needs to be for at least two nights, longer if a reduction of wetness is achieved and the circumstances allow it.
• If the child wakes at night, encourage them to use the toilet before returning to sleep. Planned waking at regular times may have practical short-term success, but there is no evidence it promotes long-term dryness.¹
• If there are some dry nights, a positive reward system may be tried (reward drinking the right quantities during the day, toilet before bed, helping change sheets, but don't take rewards away for wet nights).¹

Older children without severe daytime symptoms

• Again, ensure adequate but not excessive fluid intake during the day (age 9-13: 1,200-2,300 ml, age 14-18: 1,400-2,500 ml+).
• Elicit the child's view on the problem and whether they feel it needs treatment.
• Advise regular use of toilet during the day and before bed.
• If the child wakes at night, encourage them to use the toilet before returning to sleep. Planned waking at regular times may have practical short-term success (and can be used by young people who have not responded to other treatment), but there is no evidence it promotes long-term dryness once discontinued.¹

Referral criteria

Refer children with:

• Persistent daytime symptoms. Consider referring any child (aged >2) who is struggling to remain dry during the day, in spite of awareness of need to pass urine, and who knows how to use toilet.¹
• History of recurrent UTIs.
• Any suspected physical or neurological problems
• Developmental attention or learning difficulties, behavioural or family problems - involve an expert with psychological expertise.

Primary care management

• An enuresis alarm may be considered as first-line treatment if the above has failed and the child is still wetting the bed frequently. It is not recommended for infrequent bedwetting, nor where their carers are expressing emotional difficulty or anger coping with the burden of frequent wet beds.
  • Alarms can be bought from Education and Resources for Improving Childhood Continence (ERIC).¹⁵ They may be available for loan through a local enuresis advisor or clinic.
  • Assess response after 4 weeks; stop only if there are no early signs of response (significant improvement).
  • Continue until a minimum of 14 dry nights have been achieved. Assess and consider alternative treatment after 3 months unless still improving.
  • Note: an alarm may help some children with daytime symptoms or secondary enuresis.
• Desmopressin should be offered first-line to children aged over 7 where rapid control is needed or an alarm is inappropriate; otherwise, it should be used second-line after an alarm has been tried.⁴ It may be used in children aged 5-7 if treatment is required under the same circumstances.
  • If used following a trial with the alarm, desmopressin may be used initially with the alarm, unless the alarm is no longer acceptable.⁴
  • Desmopressin - initially use 200 micrograms Desmotabs® (or 120 micrograms for DesmoMelt®) at bedtime. Consider increasing after 2 weeks.
  • Assess success after 4 weeks and continue for 3 months if there is some response.
  • Desmopressin can be used in children with emotional, developmental or learning difficulties, and children with sickle cell disease, as long as they can comply with night-time fluid restriction (but stop drug during a sickle cell crisis). Restrict fluids from 1 hour before dose to 8 hours after.
    Cystic fibrosis, renal impairment, raised intracranial pressure and cardiac insufficiency are noteworthy contra-indications in children - discuss with consultant.¹⁶
  • Desmopressin can be given 1-2 hours before bedtime in resistant cases (same rules about fluid restriction).
  • If desmopressin is being used long-term, withdraw for one week every 3 months to see if dryness has been achieved.

Refer children for further assessment who have not responded to courses of treatment with an alarm and/or desmopressin.
Specialists may consider:

• Desmopressin with an anticholinergic, taken together at bedtime (may take 6 months for full benefit).
• Imipramine (tricyclic) - third-line treatment with high relapse rates - trial usually for 3 months.

Complications

• Bedwetting can be very distressing, especially for older children and it may lead to social isolation, bullying and low self-esteem. Whilst an expectant approach is appropriate for younger children, older children need a more active approach.
• If enuresis persists into adult life, there may be severe psychosocial problems affecting self-esteem, careers, social life and personal relationships. It is unpleasant to sleep with a bedwetter.
• Parents have extra work and cost of extra laundry along with the additional stress of caring for a child with enuresis. Up to 30% of parents become intolerant of the enuresis and consequently also of their child.

Prognosis

The majority of patients who do not have a serious neurological defect or severe learning difficulties can expect to achieve nocturnal continence sooner or later. Primary enuresis without daytime symptoms resolves in approximately 15% of children each year.¹ Even after dry nights have been reliably achieved, the occasional 'accident' is still to be expected and is no cause for concern unless there is apparent regression. Those with a family history of late nocturnal continence, those with behavioural disorders and those with developmental delay will take longer. Boys tend to take longer than girls but all cases are highly variable.

In 1% of patients enuresis will persist into adulthood¹ and one study found that children with the most severe form of bedwetting are likely to persist with the problem.³ A typical scenario is after a night of heavy consumption of beer. The alcohol causes deep sleep and the volume puts the bladder under great stress.

Document references

1. Bedwetting (enuresis), Clinical Knowledge Summaries (January 2011)
2. Robson WL; Current management of nocturnal enuresis. Curr Opin Urol. 2008 Jul;18(4):425-30. [abstract]
3. Butler RJ, Heron J; The prevalence of infrequent bedwetting and nocturnal enuresis in childhood. A large British cohort. Scand J Urol Nephrol. 2008;42(3):257-64. [abstract]
4. Nocturnal enuresis - the management of bedwetting in children and young people, NICE Clinical Guideline (October 2010); The management of bedwetting and nocturnal enuresis in children and young people
5. Butler RJ, Golding J, Northstone K; Nocturnal enuresis at 7.5 years old: prevalence and analysis of clinical signs. BJU Int. 2005 Aug;96(3):404-10. [abstract]
6. Wang QW, Wen JG, Zhu QH, et al; The effect of familial aggregation on the children with primary nocturnal enuresis. Neurourol Urodyn. 2008 Nov 14. [abstract]
7. Backwin H. The genetics of enuresis. In: Colvin I, McKeith, RC, Meadow, SR, eds; Philadelphia: Lippincott, 1973
8. Sureshkumar P, Jones M, Caldwell PH, et al; Risk Factors for Nocturnal Enuresis in School-Age Children. J Urol. 2009 Oct 19. [abstract]
9. Touchette E, Petit D, Paquet J, et al; Bed-wetting and its association with developmental milestones in early childhood. Arch Pediatr Adolesc Med. 2005 Dec;159(12):1129-34. [abstract]
10. Elia J, Takeda T, Deberardinis R, et al; Nocturnal enuresis: a suggestive endophenotype marker for a subgroup of J Pediatr. 2009 Aug;155(2):239-44.e5. Epub 2009 May 15. [abstract]
11. McGrath KH, Caldwell PH, Jones MP; The frequency of constipation in children with nocturnal enuresis: a comparison with parental reporting. J Paediatr Child Health. 2008 Jan;44(1-2):19-27. [abstract]
12. Loening-Baucke V; Urinary incontinence and urinary tract infection and their resolution with treatment of chronic constipation of childhood. Pediatrics. 1997 Aug;100(2 Pt 1):228-32. [abstract]
13. Stone J, Malone PS, Atwill D, et al; Symptoms of sleep-disordered breathing in children with nocturnal enuresis. J Pediatr Urol. 2008 Jun;4(3):197-202. Epub 2008 Jan 22. [abstract]
14. Rona RJ, Li L, Chinn S; Determinants of nocturnal enuresis in England and Scotland in the '90s. Dev Med Child Neurol. 1997 Oct;39(10):677-81. [abstract]
15. ERIC (Education and Resources for Improving Childhood Continence) Enuresis resources for patients and professionals
16. Summmary of Product Characteristics - DesmoMelt® 120 micrograms oral lyophilisate (desmopressin acetate); Ferring Pharmaceuticals Ltd Updated July 2008, last accessed November 2009

Internet and further reading

• ERIC (Education and Resources for Improving Childhood Continence) Enuresis resources for patients and professionals

Acknowledgements