Enuresis

Basics

Classification
- Primary nocturnal enuresis (NE): 80% of all cases; person 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
NE: intermittent nocturnal incontinence after the anticipated age of bladder control (age 5 years)
- Primary monosymptomatic NE (PMNE): bed-wetting with no history of bladder dysfunction or other lower urinary tract (LUT) symptoms
- Nonmonosymptomatic NE (NMNE): bed-wetting with LUT symptoms such as frequency, urgency, daytime wetting, hesitancy, straining, weak or intermittent stream, post-urination dribbling, lower abdominal or genital discomfort, or sensation of incomplete emptying
  ALERT
  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 NE

Incidence

Prevalence

Very common; 5 to 7 million children in the United States
10% of 7-year-olds; 3% of 11- to 12-year-olds; 0.5–1.7% at 16 to 17 years old (1)
2 to 3 times more common in males than females
Nocturnal > daytime (3:1)

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

A disorder of sleep arousal, a low nocturnal bladder capacity, and nocturnal polyuria are the three factors that interrelate to cause NE.
Both functional and organic causes (below); many theories, none absolutely confirmed
Detrusor instability
Deficiency of arginine vasopressin (AVP); decreased 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: urinary tract infection (UTI), occult spina bifida, ectopic ureter, lazy bladder syndrome, irritable bladder with wide bladder neck, posterior urethral valves, neurologic bladder dysfunction
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.

Genetics
Most commonly, NE is an autosomal-dominant inheritance pattern with high penetrance (90%).

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

Family history
Stressors (emotional, environmental) common in secondary enuresis (e.g., divorce, death)
Constipation and/or 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 to 12 years
Altered mental status or impaired mobility

Obstructive sleep apnea syndrome (10–54%) (2): Atrial natriuretic factor inhibits renin-angiotensin-aldosterone pathway leading to diuresis.
Constipation (33–75%) (2)
Behavioral problems (specifically ADHD in 12–17%) (2)
Overactive bladder or dysfunctional voiding (up to 41%) (2)
UTI (18–60%) (2)

There's more to see -- the rest of this topic is available only to subscribers.