The word enuresis itself comes from the Greek word for voiding and interest in the condition can be traced to ancient times. Usually, a distinction is made between primary enuresis (the child has never been dry) versus secondary enuresis (the child had the skill but lost it). Nighttime enuresis is most common whereas daytime enuresis less so (once the ability to void properly is acquired) (Shaffer et al., 1984). In DSM-5 (APA, 2013), the condition is defined based on involuntary voiding (in bed or clothes) that happens twice weekly for a period of several months after age 5 (or equivalent developmental level). The problem must not be due to a medical problem or drug and must be a source of distress or impairment. This approach is largely consistent with earlier definition. Distinctions can be made between primary or secondary enuresis (or both). For secondary enuresis, the child is usually only said to have
the condition after at least one year of being dry (Mikkelsen, 2018). The child must be at least 5 years of age or at that developmental level (a potential problem for more cognitively impaired individuals who can, and should, be toilet trained). By definition, wetting due to use of a drug or substance or medical condition is excluded. The usual distinction between primary and secondary is made.

Longitudinal studies provide rather similar rates of the condition, and it varies dramatically with age (Feehan et al., 1990). Occasional bed-wetting is fairly common and decreases as children become older. Boys are at increased risk. There may be a positive family history (in fathers). Children with developmental delays may achieve continence later than other children (Mikkelsen, 2018). By age 6, about 90% of children are dry at night. Over time, this number continues to decrease so that by age 14 about 1% of boys and 0.5% of girls are having enuretic episodes at least once a week. Risk is increased in the context of ongoing mental health problems; stress and socioeconomic disadvantage also contribute to increased risk (Rutter et al., 1973, Rutter, 1989).

Numerous theoretical models have been developed and range from the anatomic and neurologic to neuropsychological and psychodynamic (Mikkelsen, 2018). Overall developmental delay is associated with later toilet training (Matson & LoVullo, 2009). There has been some suggestion of association with specific sleep phases, but this is unclear (Neveus et al., 1999) (Box 19.1).

There are associations with psychosocial stress, and clearly, psychosocial factors can contribute to delayed toilet training or loss of skills (Joinson et al., 2007). The interrelationships of behavioral and developmental difficulties with enuresis are difficult to disentangle, although it does appear that, at least in some cases, a strong genetic component is present (von Gontard et al., 2001, 2006). In one study, positive family history was related to better outcome.

Spontaneous remission of bed-wetting is common, particularly between the ages of 5 and 7 and again in adolescence. In a given year, about 15% of children experience a spontaneous remission of the condition. As noted in the ensuing section, both psychological and pharmacologic treatments are available. As the condition is resolved, self-concept may improve (Moffatt et al., 1987).

Urinalysis is an obvious first step in evaluation of enuresis, for example, to rule out urinary tract infection as a cause. In general, invasive studies do not have a particularly high yield and are not needed unless other indications are present. Children who have problems during both night AND daytime may be more likely to exhibit structural or other problems of the urinary tract. Ultrasound evaluation is less invasive than past procedures. At times, enuresis may be seen in association with other medical conditions and physical examination should look for potentially treatable underlying conditions. Associations with other factors, for example, nocturnal enuresis that follows administration of a new medication, should be explored as relevant.