Definition of Enuresis
Enuresis is defined as repeated voiding of urine into bed or clothes at least twice weekly for at least three consecutive months in a child who is at least 5 years of age 1.
Core Diagnostic Criteria
The DSM-IV-TR definition includes both voluntary and involuntary voiding, though most clinical research excludes intentional wetting. A child can also be diagnosed with enuresis if the frequency or duration is less than the standard criteria but there is associated distress or functional impairment 1.
Classification by Timing
- Nocturnal enuresis: Voiding during sleep
- Diurnal enuresis: Wetting while awake 1
Classification by History
Primary Enuresis
Children who have never been consistently dry through the night 1. This represents the majority of cases and is twice as common as secondary enuresis 1.
Secondary Enuresis
The resumption of wetting after at least 6 months of dryness 1. This form is often associated with psychological stressors such as parental divorce, school trauma, sexual abuse, or hospitalization 1.
Classification by Associated Symptoms
Monosymptomatic Enuresis (MNE)
Nighttime bedwetting without daytime urinary symptoms 2, 3, 4, 5.
Non-Monosymptomatic Enuresis (NMNE)
Bedwetting with daytime lower urinary tract symptoms such as urgency, frequency, holding maneuvers, or daytime incontinence 2, 3, 4, 5. More than 50% of enuretic children show daytime symptoms 6.
Key Clinical Considerations
The age threshold of 5 years is critical because this represents when urinary continence is developmentally expected. Before age 4-5 years, bedwetting is considered a normal variant unless specific underlying causes are identified 1.
Primary enuresis is twice as common as secondary enuresis, and boys are affected twice as often as girls (2:1 ratio) 1. The condition is more prevalent in lower socioeconomic groups and institutionalized children 1.
Important Pathophysiological Context
The three major pathogenetic mechanisms in monosymptomatic enuresis are:
- Nocturnal polyuria (often due to lack of normal nocturnal vasopressin increase)
- Detrusor overactivity
- Increased arousal threshold (inability to wake to bladder signals) 2
It is essential to distinguish children with only nocturnal symptoms from those with daytime voiding dysfunction, as the latter group requires specialized evaluation and different treatment approaches 2.