Enuresis

Diane Tanaka

Enuresis is typically considered a childhood problem, but it affects 2% to 3% of teens and 0.5% to 2% of adults. Boys are affected more than girls by a ratio of 2:1. Even though enuresis spontaneously resolves by 15% per year, the longer enuresis persists, the lower the likelihood it will resolve spontaneously. The more severe the childhood enuresis, the more likely it will persist into adolescence and adulthood. About 53% to 82% of adolescents and young adults (AYAs) with enuresis have the moderate to severe form,¹,² defined as >3 wet nights/week. Bladder dysfunction occurs more frequently in AYAs with enuresis.¹,²,³ As enuresis negatively impacts self-esteem and emotional well-being, it is reasonable to evaluate and treat enuresis in AYAs. Certain populations of AYAs have an increased incidence of nocturnal enuresis, including those with sickle cell anemia or anorexia nervosa⁴,⁵ and those taking certain psychotropic medications. While there is reasonable evidence on effective treatments for nocturnal enuresis in children, there is a lack of evidence on treatments for AYAs.

STANDARDIZING TERMINOLOGY

The International Children’s Continence Society has standardized enuresis terminology for children and adolescents⁶:

Enuresis: Discrete episodes of urinary incontinence occurring during sleep beyond the age of 5 years, which is the age at which bladder control is achieved.

Monosymptomatic nocturnal enuresis (MNE): Enuresis occurring in AYAs without other lower urinary tract symptoms and no history of bladder dysfunction.

Primary enuresis: never achieved dryness.

Secondary nocturnal enuresis: Nighttime wetting that occurs in AYAs who have a history of 6 months of dryness. This often occurs during stressful events or a vulnerable time in the teen’s or young adult’s life. The exact cause is often unknown.

Nonmonosymptomatic Enuresis (NME): Enuresis associated with other lower urinary tract symptoms, including urgency, increased or decreased urinary frequency, straining, hesitancy, or a weak or intermittent urinary stream.

Daytime incontinence: Incontinence during the day. Among AYAs who experience nocturnal enuresis, 18% to 29% also have significant daytime symptoms.¹,²,⁷ Females often have more daytime symptoms than males and may be associated with urinary tract infections (UTIs) and obstipation.

Evidence suggests that a significant proportion, if not most, of AYAs—especially older AYAs, and those with daytime wetness or other lower urinary tract symptoms—have NME and should be referred to a specialist.³,⁸ Hence, this chapter will focus primarily on the management of AYAs with MNE, as they usually can be managed by primary care providers and adolescent medicine specialists.

ETIOLOGY OF MNE

Bladder maturation plays a key role in achieving urinary continence. The child must gain awareness of bladder filling, develop the ability to voluntarily suppress bladder contractions, and learn to coordinate sphincter and detrusor function. Daytime continence is usually achieved by 4 years of age. By age 5, most children have achieved nighttime bladder control.⁴

Major Contributors to MNE

Nocturnal Polyuria

Characterized by increased nighttime urine output. Increased fluid intake before bedtime, reduced response to antidiuretic hormone (ADH), and decreased secretion of ADH may be the mechanisms behind nocturnal polyuria.

Detrusor Overactivity

There may be a defect in the circadian rhythm of detrusor inhibition in teens with MNE. There is no clear pattern of urodynamic abnormality in MNE, unlike in AYAs with daytime incontinence. An increased rate of bladder contractions is seen during enuretic episodes, which has been confirmed with urodynamic studies. If the adolescent or young adult has MNE refractory to treatment, consider bladder dysfunction.

Disturbed Sleep

Excessively deep sleep seems to contribute to MNE. Sleep studies have found that teens with MNE are more difficult to arouse than controls; may have frequent cortical arousals associated with unstable bladder contractions, but are unable to awaken completely; and that enuretic episodes may occur during any sleep stage, but can primarily occur during non-REM sleep.⁴,⁹,¹⁰ Insomnia is found more often in AYAs with severe enuresis.¹⁰

Other Contributors to MNE

Maturational Delay

Spontaneous resolution of enuresis provides support for the role of maturational delay. An increased incidence of minor neurologic dysfunctions, including minor motor dysfunctions, has been found in studies of enuretic children.¹¹ However, studies have not investigated whether neurologic dysfunctions play a role in enuresis in AYAs.

Genetics

There is a 68% concordance between monozygotic twins and a 36% concordance between dizygotic twins. When both parents have a history of enuresis, 77% of their children are affected; in contrast, if neither parent has a history of enuresis, only 15% of their children are affected. An autosomal dominant form of primary nocturnal enuresis has been linked to chromosome 13q13-q14.3 in Danish families. Other genetic loci for enuresis have been found on chromosomes 12q13-q21 and 22q11.⁴,¹¹,¹²,¹³ Thirty percent of enuresis cases are sporadic, 50% appear to be autosomal dominant, and the remaining cases show autosomal recessive inheritance or polygenic inheritance.¹³,¹⁴

Abnormal Secretion of ADH

Studies indicate that decreased nocturnal secretion of ADH is a factor in the etiology of MNE.¹⁵ There is evidence that the response to ADH secretion is subject to maturational development.

Small Bladder Capacity

The expected bladder capacity (in mL) for age can be calculated by multiplying the adolescent’s age in years by 30 and then adding 30; after age 12, the estimated bladder capacity levels off at 390 mL.⁶ Enuretic children have smaller bladder capacities than age-matched children without enuresis.⁴,¹⁶,¹⁷,¹⁸ Early studies in children provided evidence that smaller bladder capacity is actually due to a functional decrease in capacity.⁴ It is unclear to what extent this plays a role in AYAs.

Psychological Factors

Psychological stressors do not seem to cause enuresis. It is important to remember that the AYAs are not deliberately wetting the bed. An increased prevalence of emotional difficulties, including poor self-esteem, family stress, and family isolation, has been described in affected adolescents. However, this may be secondary to the enuresis rather than the cause. In many cultures, enuresis is psychosocially stigmatizing. Enuresis has been described in AYAs with anorexia nervosa.⁵ It has also been described to occur early in treatment with second-generation antipsychotic medication, in particular clozapine.¹⁸ ADHD and nocturnal enuresis have been noted to co-occur in children,¹⁹ but persistence of this co-occurrence into AYAs has not been described.

DIAGNOSIS

A thorough history, a focused physical exam, and a urinalysis are all that are needed to evaluate enuresis. Significant organic lesions are infrequent with MNE. A good voiding history is essential. The prevalence of an organic or psychological cause is more prevalent in secondary enuresis and daytime incontinence.

History

The history is the cornerstone of the evaluation of AYAs with enuresis: