Bedwetting (enuresis)
Exam Tips
- First classify: primary vs secondary, and monosymptomatic vs non-monosymptomatic; this determines investigation intensity and treatment choice.
- Do not routinely dip urine in every child with bedwetting; test when recent onset, daytime symptoms, systemic illness, or UTI/diabetes features are present.
- Enuresis alarm is first-line for long-term cure; desmopressin gives faster short-term dryness but has higher relapse after stopping.
- Always ask about constipation and daytime LUTS; treating bowel dysfunction can significantly improve enuresis outcomes.
- Safety viva point: desmopressin requires overnight fluid restriction and counselling on hyponatraemia symptoms.
Definition
Nocturnal enuresis (bedwetting) is involuntary voiding during sleep in a child aged 5 years or older, when persistent wet nights are developmentally unexpected. It is classified as primary (never dry for a sustained period) or secondary (recurs after at least 6 months of dryness), and may occur with or without daytime lower urinary tract symptoms.
Pathophysiology
Bedwetting is usually multifactorial and reflects a mismatch between nocturnal urine production, functional bladder capacity, and sleep arousal. In monosymptomatic primary enuresis, common mechanisms are reduced arousal to bladder signals, nocturnal polyuria (often related to relative nocturnal vasopressin insufficiency), and/or detrusor overactivity with reduced nocturnal bladder capacity. Non-monosymptomatic or secondary enuresis is more likely to have an underlying contributor (for example constipation, UTI, diabetes mellitus, sleep-disordered breathing, neuro-urological disease, or psychosocial stress). See figure in paediatric urology teaching texts illustrating the "arousal-bladder-polyuria" triad.
Risk Factors
- Family history of enuresis (strong hereditary association)
- Male sex
- Developmental delay (physical or intellectual)
- Constipation or faecal incontinence
- Daytime urinary incontinence/lower urinary tract symptoms
- Neurodevelopmental or mental health conditions (for example ADHD, autism, anxiety/depression, conduct disorder)
- Sleep-disordered breathing/obstructive sleep apnoea symptoms
Clinical Features
Symptoms
- Involuntary wetting during sleep (frequency: occasional to nightly; may occur more than once per night)
- History of never being dry at night (primary) or relapse after at least 6 months dryness (secondary)
- Possible daytime urgency, frequency (>7/day), daytime wetting, dysuria, weak stream/straining, or infrequent voiding (<4/day) in non-monosymptomatic cases
- Possible associated constipation (hard stools, painful defecation, infrequent bowel motions)
- Sleep symptoms such as snoring, witnessed apnoeas, restless sleep, daytime somnolence
Signs
- Often normal examination in primary monosymptomatic enuresis
- Abdominal faecal loading or palpable stool burden suggesting constipation
- Adenotonsillar hypertrophy or mouth-breathing suggesting upper airway obstruction
- Poor growth, dehydration, or weight loss suggesting diabetes/other systemic illness
- Neurological/spinal red flags (abnormal lower limb neurology, sacral dimple/hair tuft) suggesting neurogenic bladder/spinal dysraphism
Investigations
Management
Lifestyle Modifications
- Provide reassurance and de-stigmatise: bedwetting is involuntary and common; avoid punishment
- Optimise daytime fluids (regular intake across the day, avoid large late-evening boluses), and reduce caffeine/fizzy drinks
- Establish regular daytime toileting and pre-bed voiding; treat coexisting constipation
- Use reward systems for agreed behaviours (for example toileting routine), not for "dry nights" alone
- First-line active treatment in motivated children is usually an enuresis alarm (best long-term cure rates), with family education on consistent use
- Address practical/home factors (easy night toilet access, school trip planning, emotional support)
Pharmacological Treatment
Antidiuretic (vasopressin analogue)
- Desmopressin oral tablet 200 micrograms at bedtime; if needed increase to 400 micrograms at bedtime
- Desmopressin oral lyophilisate (melt) 120 micrograms at bedtime; if needed increase to 240 micrograms at bedtime
Useful for rapid/short-term dryness (for example sleepovers) and when alarm is unsuitable or unacceptable. Strict fluid restriction is essential from 1 hour before to 8 hours after dose to reduce hyponatraemia/water intoxication risk. Avoid in habitual or psychogenic polydipsia, known hyponatraemia, significant renal impairment, or conditions/drugs increasing fluid/electrolyte risk; counsel on headache, nausea, vomiting, confusion, and seizures as red-flag adverse effects.
Tricyclic antidepressant (specialist/second-line)
- Imipramine for nocturnal enuresis in children 7-17 years: 25 mg at bedtime initially, increased if needed (typically up to 50 mg in older children; max 75 mg nightly in adolescents depending on age/response)
Reserve for specialist use when other options fail due to safety profile and relapse risk. Contraindications/cautions include cardiac disease, seizure risk, overdose toxicity, and interaction burden; keep supplies small and monitor closely.
Antimuscarinic add-on (if overactive bladder/daytime symptoms, specialist-led)
- Oxybutynin (age-dependent paediatric dosing per BNF; often low-dose initiation with titration)
Consider when enuresis coexists with daytime urgency/frequency or proven overactive bladder, often combined with desmopressin in specialist pathways. Watch for anticholinergic adverse effects (constipation, dry mouth, blurred vision), which may worsen bladder-bowel dysfunction.
Complications
- Low self-esteem, shame, social withdrawal, and avoidance of sleepovers/school trips
- Behavioural distress and family conflict, including financial burden from laundry/bedding/pull-ups
- Risk of punitive parenting or safeguarding concerns in a minority of cases
- Persistent enuresis into adolescence/adulthood in a small proportion
- Adverse drug events if treatment is unsafe (notably desmopressin-associated hyponatraemia)
Prognosis
Most children with primary monosymptomatic enuresis improve with age, with spontaneous resolution in a meaningful minority each year (commonly quoted around 5-15% annually). Prognosis is less favourable when wetting is very frequent/nightly, when daytime symptoms persist, or when comorbid bladder-bowel dysfunction is uncorrected; a small group continues to have symptoms into adulthood.
Sources & References
✅NICE Guidelines(1)
- Bedwetting (enuresis)[overview]