Treatment for nocturnal enuresis: the current state in Japan.

Nocturnal enuresis is common problem in children with a prevalence as high as 20% among children aged 5. Though nocturnal enuresis does not directly impose imminent danger to a patient's life, children with enuresis and their parents can be psychologically suffering in day-to-day life, including in school activities. Therefore, it is important to provide an explanation regarding the cause of nocturnal enuresis, how to approach the disorder, the course, and the outlook leading to the planned treatment. The cause of enuresis is considered to be a mismatch between nocturnal diuresis and nocturnal bladder capacity, nocturnal polyuria due to a lack of circadian change in antidiuretic hormones, and a developmental delay in the voiding mechanisms. Therefore, patients can be classified as the type associated with a large amount of urine at night (polyuria type), the type that is associated with a functionally small bladder capacity (bladder type), the type associated with both the aforementioned (mixed type), or the type that does not fall under any of these (normal type). Based on this logic, although the International Children's Continence Society has issued the standardization document, in which the enuresis alarm and desmopressin therapy are recommended as the first line treatment, a different tack has been taken in Japan, where the therapeutic strategy is plotted depending on the type of enuresis; pharmacotherapy for enuretic children aged 6 years or older includes desmopressin acetate for polyuria type, anticholinergic agents for bladder type, and a combination of these agents for mixed type.