11. Elimination Disorders
11.1. Enuresis
11.2. Encopresis
Elimination Disorders involve the inappropriate elimination of urine or feces
and are usually first diagnosed in childhood or adolescence. This group of disorders includes
enuresis, the repeated voiding of urine into inappropriate places, and encopresis, the
repeated passage of feces into inappropriate places. Subtypes are provided to differentiate
nocturnal from diurnal (i.e., during waking hours) voiding for enuresis and the presence or
absence of constipation and overflow incontinence for encopresis. Although there are minimum
age requirements for diagnosis of both disorders, these are based on developmental
age and not solely on chronological age. Both disorders may be volimtary or involuntary.
Although these disorders typically occur separately, co-occurrence may also be observed.
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 least twice a week for at least 3 consecutive months or must cause clinically significant distress or impairment in social, academic (occupational), or other important areas of functioning (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 attributable to the physiological effects of a substance (e.g., a diuretic, an antipsychotic medication) or another medical condition (e.g., diabetes, spina bifida, a seizure disorder) (Criterion D).
Ehiring 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 daytime (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 persists 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.
Enuresis has beeh reported in a variety of European, African, and Asian countries as well as in the United States. At a national level, prevalence rates are remarkably similar, and there is great similarity in the developmental trajectories found in different countries. There are very high rates of enuresis in orphanages and other residential institutions, likely related to the mode and environment in which toilet training occurs.
Nocturnal enuresis is more common in males. Diurnal incontinence is more common in females. The relative risk of having a child who develops enuresis is greater for previously enuretic fathers than for previously enuretic mothers.
The amount of impairment associated with enuresis is a function of the limitation on the
child's social activities (e.g., ineligibility for sleep-away camp) or its effect on the child's
self-esteem, the degree of social ostracism by peers, and the anger, punishment, and rejection
on the part of caregivers.
The essential feature of encopresis is repeated passage of feces into inappropriate places (e.g., clothing or floor) (Criterion A). Most often the passage is involimtary but occasionally may be intentional. The event must occur at least once a month for at least 3 months (Criterion B), and the chronological age of the child must be at least 4 years (or for children with developmental delays, the mental age must be at least 4 years) (Criterion C). The fecal incontinence must not be exclusively attributable to the physiological effects of a substance (e.g., laxatives) or another medical condition except through a mechanism involving constipation (Criterion D). When the passage of feces is involuntary rather than intentional, it is often related to constipation, impaction, and retention with subsequent overflow. The constipation may develop for psychological reasons (e.g., anxiety about defecating in a particular place, a more general pattern of anxious or oppositional behavior), leading to avoidance of defecation. Physiological predispositions to constipation include ineffectual straining or paradoxical defecation dynamics, with contraction rather than relaxation of the external sphincter or pelvic floor during straining for defecation. Dehydration associated with a febrile illness, hypothyroidism, or a medication side effect can also induce constipation. Once constipation has developed, it may be complicated by an anal fissure, painful defecation, and further fecal retention. The consistency of the stool may vary. In some individuals the stool may be of normal or near-normal consistency. In other individuals—such as those with overflow incontinence secondary to fecal retention—it may be liquid.
The child with encopresis often feels ashamed and may wish to avoid situations (e.g., camp, school) that might lead to embarrassment. The amount of impairment is a function of the effect on the child's self-esteem, the degree of social ostracism by peers, and the anger, punishment, and rejection on the part of caregivers. Smearing feces may be deliberate or accidental, resulting from the child's attempt to clean or hide feces that were passed involuntarily. When the incontinence is clearly deliberate, features of oppositional defiant disorder or conduct disorder may also be present. Many children with encopresis and chronic constipation also have enuresis symptoms and may have associated urinary reflux in the bladder or ureters that may lead to chronic urinary infections, the symptoms of which may remit with treatment of the constipation.
It is estimated thiht approximately 1% of 5-year-olds have encopresis, and the disorder is more common in males than in females.