Description

• Nocturnal enuresis (NE): Repeated spontaneous voiding of urine during sleep after the anticipated age of bladder control (age 5)
• Daytime incontinence: Uncontrollable leakage of urine while awake
• Classification:
  • Primary NE: 1% of adult population; 80% of all cases; child/adult who has never established urinary continence on consecutive nights for a period of ≥6 months
  • Secondary NE: 20% of cases; resumption of enuresis after at least 6 months of urinary continence
• Also categorized as:
  • Monosymptomatic NE (uncomplicated): Bed wetting without lower urinary tract (LUT) symptoms other than nocturia and no history of bladder dysfunction
  • Nonmonosymptomatic NE: Bed wetting with LUT symptoms such as frequency, urgency, daytime wetting, hesitancy, straining, weak or intermittent stream, posturination dribbling, lower abdominal or genital discomfort, sensation of incomplete emptying
  • Daytime LUT condition: Bed wetting with LUT daytime symptoms
• Adult-onset NE with absent daytime incontinence is a serious symptom; complete urologic evaluation and therapy are warranted.
• System(s) affected: Nervous; Renal/Urologic
• Synonym(s): Bed wetting; Sleep enuresis; Nocturnal incontinence; Primary nocturnal enuresis

Epidemiology

• Depends on family history
• Spontaneous resolution: 15% per year, 99% children are dry by age 15

• Very common. Affects 5–7 million children in the US.
• 40% of 3-year-olds; 10% of 6-year-olds; 3% of 12-year-olds; 1% of adults
• Male > Female (3:1)
• Nocturnal > Day (3:1)

Geriatric Considerations
Infrequent; often associated with daytime incontinence (formerly referred to as diurnal enuresis)

Risk Factors

• Family history
• Stressors (emotional, environmental) common in secondary enuresis (e.g., divorce, death)
• Constipation
• Encopresis
• Organic disease: 1% of monosymptomatic NE (e.g., urologic and nonurologic causes)
• Psychological disorders:
  • Comorbid disorders are highest with secondary NE: Depression, anxiety, social phobias, conduct disorder, hyperkinetic syndrome, internalizing disorders
  • Association with ADHD; more pronounced in ages 9–12 years
  • Abuse; 11% sexually abused girls
• Altered mental status or impaired mobility

• 1/3 of all cases are sporadic
• 75% of children with enuresis have a 1st-degree relative with the condition.
• Higher rates in monozygotic vs. dizygotic twins (68% vs. 36%)
• If both parents had NE, risk in child is 77%; 44% if 1 parent affected. Parental age of resolution often predicts when child's enuresis should resolve.

General Prevention

No known measures

Pathophysiology

A disorder of sleep arousal, a low nocturnal bladder capacity, and nocturnal polyuria are the 3 factors that interrelate to cause nocturnal enuresis (1).

Etiology

• Both functional and organic causes; many theories, none absolutely confirmed
• Detrusor instability
• Deficiency of arginine vasopressin (AVP); owing to decreased inherent nocturnal AVP or decreased AVP stimulation secondary to an empty bladder (bladder distension stimulates AVP)
• Maturational delay of CNS
• Severe NE with some evidence of interaction between bladder overactivity and brain arousability: Association with children with severe NE and frequent cortical arousals in sleep
• Organic urologic causes in 1–4% of enuresis in children: UTI, occult spina bifida, ectopic ureter, lazy bladder syndrome, irritable bladder with wide bladder neck, posterior urethral valves
• Organic nonurologic causes: Epilepsy, diabetes mellitus, food allergies, obstructive sleep apnea, chronic renal failure, hyperthyroidism, pinworm infection, sickle-cell disease
• NE occurs in all stages of sleep.

Commonly Associated Conditions

• Obstructive sleep apnea syndrome; ↑ atrial natriuretic factor → inhibits renin-angiotensin-aldosterone pathway → ↑ diuresis
• Constipation (1/3 of NE patients)
• Behavioral problems (specifically ADHD)