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What is nocturnal enuresis (bedwetting)?
Nocturnal enuresis, commonly known as "bedwetting," is a type of parasomnia. Enuresis refers to the involuntary discharge of urine (leaking urine), and nocturnal enuresis specifically refers to this occurring at night.
The "Clinical Practice Guidelines for Nocturnal Enuresis 2016" adopts the definition set by the International Children's Continence Society in 2014: "bedwetting occurring at least once a month for three consecutive months in children aged 5 years or older." It further classifies bedwetting as "frequent" if it occurs four or more days a week, and "infrequent" if it occurs three or fewer days a week.
Surveys in Japan indicate that the prevalence of nocturnal enuresis is approximately 20% in children aged 5-6 years just before school enrollment, about 10% in early elementary school, around 5% over the age of 10, and 1-3% in junior high school students. It has also been reported that in rare cases, nocturnal enuresis can persist into adulthood.
Causes of Nocturnal Enuresis
Nocturnal enuresis can be classified into primary nocturnal enuresis, which has been continuous since infancy, and secondary nocturnal enuresis, which recurs after a period of being dry (absence of bedwetting for at least six months).
Primary nocturnal enuresis accounts for a higher proportion, estimated at 75-90%, while secondary nocturnal enuresis is thought to be 10-25%. Therapeutically, secondary nocturnal enuresis, despite its lower proportion, is important because individuals with it tend to experience more life stress and have a higher comorbidity with mental health disorders.
Since the causes differ between these two types, they will be discussed separately.
1. Primary Nocturnal Enuresis
The main causes of primary nocturnal enuresis include three major factors: ① nocturnal polyuria, ② detrusor overactivity, and ③ elevated arousal threshold, as well as auxiliary factors such as ④ developmental delay and genetic predisposition.
In nocturnal polyuria, it is suggested that the amount of antidiuretic hormone secreted during sleep is insufficient. Additionally, increased calcium in nocturnal urine, excessive fluid intake, and excessive protein and salt intake are also cited as influences.
In detrusor overactivity, it is suggested that when the detrusor muscle contracts during sleep, the activity of the pelvic floor muscles, which should normally be enhanced, is not.
Furthermore, it has been reported that children with monosymptomatic nocturnal enuresis have a defect in the circadian rhythm that regulates detrusor muscle inhibition.
In cases of elevated arousal threshold, it is difficult to wake the child even when prompted, suggesting a delayed development of the arousal system, making it difficult to wake up even with stimulation from the bladder.
Developmental delay is believed to improve with the development of the central nervous system.
Regarding genetic predisposition, reports indicate that the likelihood of nocturnal enuresis is 5-7 times higher if one parent had it, and 11 times higher if both parents had it. Other alleged causes include nocturnal enuresis occurring due to neglect and lack of discipline at home, or conversely, as an unconscious rebellion against excessively strict discipline.
2. Secondary Nocturnal Enuresis
The main causes of secondary nocturnal enuresis are considered to be significant mental and environmental factors. Most commonly, it emerges when a younger sibling is born, and the child tries to regain parental attention. Stress from parental divorce or mental health disorders can also be contributing factors.
Additionally, some medical conditions can lead to nocturnal enuresis. For example, psychogenic polydipsia, diabetes insipidus, and diabetes mellitus can increase nocturnal urine volume, potentially leading to nocturnal enuresis.
Treatment methods
Treatment for nocturnal enuresis includes lifestyle guidance, behavioral therapy, alarm therapy, and pharmacotherapy. Initially, lifestyle guidance and behavioral therapy are implemented. If these are not effective, alarm therapy or pharmacotherapy are considered.
Lifestyle guidance involves salt restriction at dinner, limiting fluid intake after dinner, complete voiding before bedtime, and controlling urination habits. Behavioral therapy includes rewarding dry nights and restricting fluid intake.
If these lifestyle and behavioral therapies are ineffective, more aggressive treatment is required, which includes alarm therapy or desmopressin treatment.
Alarm therapy uses an alarm that sounds when bedwetting occurs, teaching the child to associate bladder fullness with the alarm. While bedwetting may continue initially, the child gradually learns to wake up before wetting the bed. This method is considered effective, especially when bedwetting occurs three or more times a week and both the child and family are highly motivated.
Desmopressin is a medication that mimics the action of antidiuretic hormone, and its administration is known as desmopressin treatment. This treatment is used when alarm therapy has been ineffective or when families are reluctant to use alarm therapy.
【Reference】
Clinical Practice Guidelines for Nocturnal Enuresis 2016, Japanese Society of Nocturnal Enuresis
