Normal Development of Elimination
Development of control of urination and defecation involves physical and cognitive maturation and is strongly influenced by cultural norms, socioeconomic status, and practices within the United States and throughout the world. In the first half of the 20th century, toilet mastery by 18 months of age was the norm in the United States. Brazelton’s introduction of the child-centered approach and the invention of disposable diapers facilitated later toilet training. Social changes, including increased maternal work outside of the home and group child care, also have influenced the trend to later initiation of toilet training. Toilet training now usually begins after the second birthday and is achieved at about 3 years of age in middle-class white U.S. populations. Toilet training between 12 and 18 months of age continues to be accepted in lower-income families.
Prerequisites for achieving elimination in the toilet include the child’s ability to recognize the urge for urination and defecation, to get to the toilet, to understand the sequence of tasks required, to avoid oppositional behavior, and to take pride in achievement. The entire process of toilet training can take 6 months and need not be hurried. Successful parent–child interaction around the goal of toilet mastery can set the stage for future active parental teaching and training (e.g., manners, kindness, rules and laws, and limit setting).
Enuresis
Enuresis is urinary incontinence in a child who is adequately mature to have achieved continence. Enuresis is classified as diurnal (daytime) or nocturnal (nighttime). In the United States, daytime and nighttime dryness are expected by 4 and 6 years of age, respectively. Another useful classification of enuresis is primary (incontinence in a child who has never achieved dryness) and secondary (incontinence in a child who has been dry for at least 6 months).
Etiology
Enuresis is a symptom with multiple possible etiologic factors, including developmental difference, organic illness, or psychological distress. Primary enuresis often is associated with a family history of delayed acquisition of bladder control. A genetic etiology has been hypothesized, and familial groups with autosomal dominant phenotypic patterns for nocturnal enuresis have been identified. Although most children with enuresis do not have a psychiatric disorder, stressful life events can trigger loss of bladder control. Sleep physiology may play a role in the etiology of nocturnal enuresis, with a high arousal threshold commonly noted. In a subgroup of enuretic children, nocturnal polyuria relates to a lack of a nocturnal vasopressin peak. Another possible etiology is malfunction of the detrusor muscle with a tendency for involuntary contractions even when the bladder contains small amounts of urine. Reduced bladder capacity can be associated with enuresis and is commonly seen in children who have chronic constipation with a large dilated distal colon, which impinges on the bladder.
Epidemiology
Enuresis is the most common urologic condition in children. Nocturnal enuresis has a reported prevalence of 15% in 5-year-olds, 7% in 8-year-olds, and 1% in 15-year-olds. The spontaneous remission rate is reported to be 15% per year. The odds ratio of nocturnal enuresis in boys compared with girls is 1.4:1. The prevalence of daytime enuresis is lower than nocturnal enuresis but has a female predominance, 1.5:1 at 7 years of age. Of children with enuresis, 22% wet during the day only, 17% wet during the day and at night, and 61% wet at night only.
Clinical Manifestations
Decision-Making Algorithm
Enuresis
The history focuses on elucidating the pattern of voiding including frequency, timing (diurnal/nocturnal), associated conditions or stressful events (e.g., bad dreams, consumption of caffeinated beverages, or exhausting days), and whether it is primary or secondary enuresis. A review of systems should include a developmental history and detailed information about the neurologic, urinary, and gastrointestinal systems (including patterns of defecation). A history of sleep patterns is important, including snoring, parasomnias, and timing of nighttime urination. A family history often reveals that one or both parents had enuresis as children. Although enuresis is rarely associated with child abuse, physical and sexual abuse history should be included as part of the psychosocial history. Many families have tried numerous interventions before seeking a physician’s help. Identifying these interventions and how they were carried out aids the understanding of the child’s condition and its role within the family.
The physical examination begins with observation of the child and the parent for clues about child developmental and parent-child interaction patterns. Special attention is paid to the abdominal, neurologic, and genital examination. A rectal examination is recommended if the child has constipation. Observation of voiding is recommended if a history of voiding problems, such as hesitancy or dribbling, is elicited. The lumbosacral spine should be examined for signs of spinal dysraphism or a tethered cord.
For most children with enuresis, the only laboratory test recommended is a clean catch urinalysis to look for chronic urinary tract infection (UTI), renal disease, and diabetes mellitus. Further testing, such as a urine culture, is based on the urinalysis. Children with complicated enuresis, including children with previous or current UTI, severe voiding dysfunction, or a neurologic finding, are evaluated with a renal sonogram and a voiding cystourethrogram. If vesicoureteral reflux, hydronephrosis, or posterior urethral valves are found, the child is referred to a urologist for further evaluation and treatment.
Differential Diagnosis
There is no commonly identified cause of enuresis and, in most cases, enuresis resolves by adolescence without treatment. Children with primary nocturnal enuresis are most likely to have a family history and are least likely to have an identified etiology. Children with secondary diurnal and nocturnal enuresis are more likely to have an organic etiology, such as UTI, diabetes mellitus, or diabetes insipidus, to explain their symptoms. Children with primary diurnal and nocturnal enuresis may have a neurodevelopmental condition or a problem with bladder function. Children with secondary nocturnal enuresis may have a psychosocial stressor or a sleep disturbance as a predisposing condition for enuresis.
Treatment
Treatment begins with treating any diagnosed underlying organic causes of enuresis. Elimination of underlying chronic constipation is often curative. For a child whose enuresis is not associated with an identifiable disorder, all therapies must be considered in terms of cost in time, money, disruption to the family, the treatment’s known success rate, and the child’s likelihood to recover from the condition without treatment. The most commonly used treatment options are conditioning therapy and pharmacotherapy. The clinician can also assist the family in making a plan to help the child cope with this problem until it is resolved. Many children have to live with enuresis for months to years before a cure is achieved; a few children have symptoms into adulthood. A plan for handling wet garments and linens in a nonhumiliating and hygienic manner preserves the child’s self-esteem. The child should take as much responsibility as he or she is able, depending on age, development, and family culture.
The most widely used conditioning therapy for nocturnal enuresis is the enuresis alarm. Enuresis alarms have an initial success rate of 30-60% with a significant relapse rate. The alarm is worn on the wrist or clipped onto the pajama and has a probe that is placed in the underpants or pajamas in front of the urethra. The alarm sounds when the first drop of urine contacts the probe. The child is instructed to get up and finish voiding in the bathroom when the alarm sounds.
Pharmacotherapy for nighttime enuresis includes desmopressin acetate and, rarely, tricyclic antidepressants. Desmopressin decreases urine production and has proved to be safe in the treatment of enuresis. The oral medication is started at 0.2 mg per dose (one dose at bedtime) and on subsequent nights is increased to 0.4 mg and then to 0.6 mg if needed. This treatment must be considered symptomatic, not curative, and has a relapse rate of 90% when the medication is discontinued. Imipramine, now rarely used for enuresis, reduces the frequency of nighttime wetting, and the initial success rate is 50%. Imipramine is effective during treatment only, with a relapse rate of 90% on discontinuation of the medication. The most important contraindication is the risk of overdose (associated with fatal cardiac arrhythmia).
Complications
The psychological consequences can be severe. Families can minimize the impact on the child’s self-esteem by avoiding punitive approaches and ensuring that the child is competent to handle issues of their own comfort, hygiene, and aesthetics.
Prevention
Appropriate anticipatory guidance to educate parents that bed-wetting is common in early childhood helps alleviate considerable anxiety.
Functional Constipation and Soiling
Constipation is decreased frequency of bowel movements, usually associated with a hard stool consistency. The occurrence of pain at defecation frequently accompanies constipation. Although underlying gastrointestinal, endocrinologic, or neurologic disorders can cause constipation, functional constipation implies that there is no identifiable causative organic condition. Encopresis is the regular, voluntary, or involuntary passage of feces into a place other than the toilet after 4 years of age. Encopresis without constipation is uncommon and may be a symptom of oppositional defiant disorder or other psychiatric illness. Soiling is the involuntary passage of stool and often is associated with fecal impaction. The normal frequency of bowel movements declines between birth and 4 years of age, beginning with greater than four stools per day to approximately one per day.
Etiology
The etiology of functional constipation and soiling includes a low-fiber diet, slow gastrointestinal transit time for neurologic or genetic reasons, and chronic withholding of bowel movements, usually because of past painful defecation experiences. Approximately 95% of children referred to a subspecialist for encopresis have no other underlying pathologic condition.
Epidemiology
In U.S. studies, 16-37% of children experience constipation between 5 and 12 years of age. Constipation with overflow soiling occurs in 1-2% of preschool children and 4% of school-aged children. The incidence of constipation and soiling is equal in preschool girls and boys, whereas there is a male predominance during school age.
Clinical Manifestations
Decision-Making Algorithms 
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