The nocturnal—only subtype of enuresis, sometimes referred to as monosymptomutic enu re- sis, is the most common subtype and involves incontinence only during nighttime sleep, typically during the first one—third of the night. The diurnal-only subtype occurs in the absence of noctumal enuresis and may be referred to simply as urinary incontinence. Indi- viduals with this subtype can be divided into two groups. Individuals with ”urge incon- tinence” have sudden urge symptoms and detrusor instability, whereas individuals with ”voiding postponement” consciously defer micturition urges until incontinence results.
The nocturnal-and-diumal subtype is also known as nonmonosymptomutz'c enuresis.
The essential feature of enuresis is repeated voiding of urine during the day or at night into bed or clothes (Criterion A). Most often the voiding is involuntary, but occasionally it may be intentional. To qualify for a diagnosis of enuresis, the voiding of urine must occur at tress or impairment in social, academic (occupational), or other important areas of func- tioning (Criterion B). The individual must have reached an age at which continence is expected (i.e., a chronological age of at least 5 years or, for children with developmental delays, a mental age of at least 5 years) (Criterion C). The urinary incontinence is not at- tributable to the physiological effects of a substance (e.g., a diuretic, an antipsychotic med- ication) or another medical condition (e.g., diabetes, spina bifida, a seizure disorder) (Criterion D).
During nocturnal enuresis, occasionally the voiding takes place during rapid eye movement (REM) sleep, and the child may recall a dream that involved the act of urinating. During day- time (diurnal) enuresis, the child defers voiding until incontinence occurs, sometimes because of a reluctance to use the toilet as a result of social anxiety or a preoccupation with school or play activity. The enuretic event most commonly occurs in the early afternoon on school days and may be associated with symptoms of disruptive behavior. The enuresis commonly per- sists after appropriate treatment of an associated infection.
The prevalence of enuresis is 5%—10% among 5-year-olds, 3%—5% among 10-year-olds, and around 1% among individuals 15 years or older.
Two types of course of enuresis have been described: a ”primary" type, in which the indi— vidual has never established urinary continence, and a I“secondary” type, in which the dis- turbance develops after a period of established urinary continence. There are no differences in prevalence of comorbid mental disorders between the two types. By definition, primary enuresis begins at age 5 years. The most common time for the onset of secondary enuresis is between ages 5 and 8 years, but it may occur at any time. After age 5 years, the rate of spon- taneous remission is 5%—10% per year. Most children with the disorder become continent by adolescence, but in approximately 1% of cases the disorder continues into adulthood.
Diurnal enuresis is uncommon after age 9 years. While occasional diurnal incontinence is not uncommon in middle childhood, it is substantially more common in those who also have persistent nocturnal enuresis. When enuresis persists into late childhood or adoles— cence, the frequency of incontinence may increase, whereas continence in early childhood is usually associated with a declining frequency of wet nights.
Environmental. A number of predisposing factors for enuresis have been suggested, in- cluding delayed or lax toilet training and psychosocial stress.