Nocturnal Enuresis

Urinary incontinence during sleep in a child of developmental age ≥5. See also constipation in childhood (a key contributing factor) and paediatric recurrent UTI.

Classification

• Monosymptomatic — no other urinary symptoms.
• Non-monosymptomatic — urinary frequency, urgency, straining, daytime wetting or polyuria are also present.
• Primary (~80%) — never continuously dry at night for >6 months.
• Secondary (~20%) — dry for ≥6 months, then relapsed.
• Frequent (>4 nights/week) vs infrequent (<4 nights/week).

Physiology and demographics

Three main contributing factors: defective sleep arousal, nocturnal polyuria (reduced nocturnal vasopressin), and bladder factors (lack of inhibition of bladder emptying during sleep, reduced capacity, or bladder overactivity — overactive-bladder children usually have daytime symptoms too).

• Prevalence: 15–20% at age 5, 5% at age 10, 1–2% at age 15; boys 3× more than girls.
• Strong familial tendency — maternal enuresis is a stronger predictor than paternal, and severe parental enuresis predicts severe enuresis in the child.
• Spontaneous resolution ~15%/year.

History

• Family history of enuresis/incontinence.
• Urinary symptoms: urgency, day-vs-night frequency, dysuria, hesitancy/ straining, stream quality, holding manoeuvres/voiding posture, retention, post-micturition dribble.
• Contributing factors: constipation, obstructive sleep apnoea.
• Associations to screen for: UTI, diabetes, psychopathology (ADHD, behavioural problems, stress/trauma, depression).
• Bowel habits — constipation or faecal incontinence.
• Fluid intake/diet; sleep pattern (children with enuresis tend to be harder to rouse, have more fragmented sleep, more daytime sleepiness and a higher rate of sleep-disordered breathing).
• General health: symptoms of diabetes, kidney disease, spina bifida occulta; BMI (enuresis more common with obesity); medications.
• Development: toilet phobias, comorbid psychological problems.
• Psychosocial impact: family/school context, motivation, parental coping (e.g. blaming the child), bullying, self-esteem.

Examination

Abdomen (enlarged bladder, constipation); spine and neurological exam; perineum/genitalia; blood pressure; growth parameters; ENT (large tonsils/ nasal obstruction, relevant to OSA).

Investigations

• Bladder diary — flow/volume chart. Expected bladder capacity = (age + 1) × 30 mL, max 400 mL.
  • Voiding >9 times/day → consider specialist assessment before starting alarm training or desmopressin.
  • Most void volumes <60% of expected capacity → suggests small bladder capacity or overactivity.
  • Overnight urine production (first morning void + wet nappy/sheet weight) >130% of expected capacity → nocturnal polyuria — consider diabetes insipidus.
• Urine dipstick and culture — excludes UTI, diabetes mellitus, proteinuria.

Management

Treatment is recommended from age 5 onward, but delay active treatment until the child is willing and able to comply (~age 7).

Initial conservative measures (all children)

Reassurance (most children grow out of it); don’t punish the child; praise dry nights; night light; absorbent pyjama pants; shower/bath before school to avoid teasing; waterproof mattress cover; rewards/incentives; consider scheduled waking before parents go to bed.

Urotherapy

Improve urination habits: increase daytime fluids (earlier in the day, 6 evenly spaced drinks), avoid caffeine, void every 2–3 hours, aggressively treat constipation, reduce pre-bedtime fluid.

Monosymptomatic enuresis

• Alarm training — recommended after conservative measures fail, for children ≥5.5 years. A buzzer sounds on voiding to retrain the arousal response; takes ~3 weeks to recognise the sensation and ~12 weeks to achieve dryness (continue for 14 consecutive dry nights). Requires real commitment — successful in ~⅔ of children. “Over-learning” (extra fluids at bedtime once dry) helps prevent relapse.
• Desmopressin if no improvement after 3 months of alarm training — very effective but with a high relapse rate.
  • Sublingual melt 120 mcg 1 hr before bed, up to 240 mcg.
  • Tablet 200 mcg 1 hr before bed, up to 400 mcg.
  • Nasal spray 1 puff (10 mcg) — risk of hyponatraemia, generally avoided in favour of oral formulations.
  • Restrict fluids from 1 hr before to 8 hrs after dosing.
  • Particularly useful for school camps/sleepovers.
  • Other options: anticholinergics, TCAs, medication+alarm combinations — seek specialist (nocturnal enuresis clinic) input.
• Refer to a specialist paediatric continence service if no improvement after 6 months.

Non-monosymptomatic enuresis

• Address daytime symptoms first.
• Overactive bladder features (urgency, frequency, holding behaviours, small capacity) → refer for urological investigation; a trial anticholinergic can bridge the wait (monitor for constipation, dry mouth, flushing).
• Behavioural interventions; if failing after 3 months, consider alarm training or desmopressin (≥5 years).

Referral triggers

Neurogenic or structural anomaly, or comorbid faecal incontinence → refer to paediatric urology/continence service. Suspected diabetes mellitus or insipidus → paediatric endocrinology. Always treat any constipation or UTI first.