Nocturnal enuresis or bedwetting

Kristy is a 5-year-old girl; her mother has brought her in because she has started kindergarten. She has been invited to have a sleepover at a family friend’s house; however, she still wets the bed most nights of the week and wonders how to manage this.

Attaining continence – both daytime and nighttime – is a developmental milestone with a significant normal variation affected by genetic and environmental factors.

At five years of age, approximately 15% of children continue to experience nocturnal enuresis (more commonly known as bedwetting). Every year beyond this, there is spontaneous resolution in ~15% of affected children (although it should be noted that the longer the duration of bedwetting, the lower the likelihood of spontaneous resolution).

Boys are more commonly affected than girls (2:1), and there is a strong family predisposition (both parents = 77%, single parent = 43%). Only one-third of those affected will seek medical attention.

What is nocturnal enuresis?

Nocturnal enuresis is episodes of urinary incontinence during sleep in children ≥5 years of age. It may be further subdivided into monosymptomatic (uncomplicated) and non-monosymptomatic (complicated or polysymptomatic).

• Monosymptomatic: incontinence is present without other symptoms of lower urinary tract/gastrointestinal tract
• Non-monosymptomatic: incontinence associated with other symptoms including but not limited to
  • Polyuria/oliguria (8/3 times per day respectively)
  • Urgency, hesitancy, intermittency
  • Straining/holding manoeuvres
  • Weak stream, dribbling
  • A feeling of incomplete emptying
  • Pain

When episodes additionally occur during the day, it is more appropriately referred to as diurnal enuresis/incontinence.

Incontinence should be classified as primary or secondary.

• Primary: the child has never been dry
• Secondary: the child has been dry for a period of at least six months.

Why does nocturnal enuresis occur?

Nocturnal enuresis results from inappropriate emptying of the bladder by the child and from a mismatch between the bladder’s neurones and the child’s conscious state. This may be due to a multitude of factors, including:

• Maturation delay
• Genetic factors
• Nocturnal polyuria – this may be due to fluid intake, reduced response to antidiuretic hormone (ADH) and/or reduced production of ADH.
• Disturbed sleep in the child (controversial)
• Small bladder capacity
• Detrusor overactivity

These factors may be primary to the child (e.g. genetic factors) or secondary to an underlying condition (e.g. polyuria secondary to undiagnosed diabetes insipidus)

How to evaluate a child with nocturnal enuresis?

It’s almost all in the history – search for red flags!

History:

• Onset
• Previously dry?
• Daytime symptoms (non-monosymptomatic NE)
• Frequency, amount
• Response to episodes
• Fluid habits
• Bowel habits
• Sleep routines

Examination:

• Height/weight
• BP
• Tonsillar hypertrophy/adenoidal facies
• Abdomen (distended bladder, faecal mass)
• Spine
• Lower limb neurology
• Perianal/vulval inflammation (pinworms)

Do you need to do investigations?

Investigations are unnecessary for all patients and should be guided by history and examination. Consider:

• Blood sugar level (fingerprick)
• Urinalysis (m/c/s, electrolytes)

Imaging and blood tests are not routinely indicated.

What are the treatment options?

Important things to remember in treatment:

• Tricyclic medications are not recommended as they are less effective and have a higher risk of adverse effects
• Intranasal desmopressin is not recommended due to the risk of hyponatraemia
• There are high rates of relapse when desmopressin is discontinued (60 – 70%); therefore, it is best used as a short-term measure (e.g.. for going to camp) whilst awaiting spontaneous resolution.
• Desmopressin should not be used in those who are unable to adhere to fluid restrictions (due to the risk of hyponatraemia)
• Treatments with weak evidence include elimination diet, hypnosis, retention control (holding urine for progressively longer periods), biofeedback, acupuncture, scheduled awakenings, caffeine restriction.

Take-home messages

It doesn’t require treatment in those under the age of 6

It is common although undertreated despite treatment options (and families potentially being eligible for funding)

It is usually a primary disorder rather than secondary to an underlying medical condition (although maybe particularly exacerbated by constipation)

Investigations are not routinely required

Treatment requires a motivated family, with behavioural measures and bedwetting alarms being the first line of treatment.

Selected references

Tu, Baskin, Arnhym et al (2019) “Nocturnal Enuresis in Childre: Etiology and Evaluation”. UpToDate.

Tu, Baskin, FAAP (2019). “Nocturnal Enuresis in Children: Management”. UpToDate.

The Royal Childrens Hospital. (2019). “Enuresis – Bedwetting and Monosymptomatic Enuresis.” Melbourne. Retrieved from: https://www.rch.org.au/clinicalguide/guideline_index/Enuresis_-_Bed_wetting_and_Monosymptomatic_Enuresis/

Thiedke C. “Nocturnal Enuresis”. American Family Physician (2003); April 1; 67(7): 1499 – 1506

Ramakrishnan K. “Evaluation and treatment of enuresis”. American Family Physician (2008); August 15; 78(4): 489 – 496.