▪ Elimination Disorders: Enuresis and Encopresis

BACKGROUND

In Western countries, toilet training is a process that is typically completed in toddlerhood. In the United States, this typically starts between the ages of 18 months and 3 years, with boys usually being trained slightly later than girls. Some cultures encourage earlier and others later toilet training. Toilet training goes most smoothly when there is consistency in approach and emphasis on positive reinforcement. The process is facilitated by several other factors, including, the required motor abilities of the child, the child’s cognitive ability to understand what is desired, and a desire to please the parents or caregivers. The absence of any one of these can lead to difficulties. As Piaget noted, the child’s understanding of what it means for things to be living may be a further complication (young children tend to assume that anything that comes from a living thing must be alive, a potential source of confusion for toilet training). Complications can also arise because of inconsistency in approach on the part of parents or through use of a harsh or punitive approach. Parents have been preoccupied with the best ways to achieve toilet training for thousands of years.

ENURESIS

Definition and Clinical Description

Primary enuresis occurs when the child has never been fully toilet trained for urine; in secondary enuresis, this was once achieved (for at least a year). Daytime wetting (diurnal enuresis) is less common as an isolated phenomenon than night wetting (nocturnal enuresis). As defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), functional enuresis is defined by “repeated voiding” into bed or clothes (in either day or night) and must be “clinically significant,” meaning either because of its frequency (several times a week for multiple consecutive months) or because it is the source of distress or impairment. The child must have an age (or developmental level) of 5 years, and the condition is not solely attributable to a general medical condition or substance. The type (nocturnal, diurnal, or both) can also be
specified. A distinction between primary and secondary enuresis is also made, although the definition is somewhat imprecise, indicating that the secondary form develops only after a period of established urinary continence. Typically, the secondary form develops between ages 5 and 7 years.

Epidemiology and Demography

Several different longitudinal studies have yielded rather similar findings on the prevalence of enuresis by age group. Boys are more likely than girls to exhibit enuresis. By age 6 years, about 90% of children are dry at night. There is a continued decrease in bed wetting with age so that, for example, by age 14 years, about 1% of boys and 0.5% of girls have enuretic episodes at least once a week. In addition to particular vulnerabilities within the child, psychosocial stress and socioeconomic disadvantage also contribute to increased risk. The condition also tends to run in families.

Etiology

Many different theories have been proposed to account for enuresis. Some have focused on anatomical abnormalities, others on neuropsychological or neurological immaturities, and still others on psychogenic or psychodynamic explanations. There is clearly a relationship between delayed development and later toilet training, and there is some suggestion of a complex interaction of factors (e.g., children with smaller bladders may be more likely to have both developmental and behavioral problems). Other work has been consistent with a notion of general neurophysiologic immaturity. Physical factors (e.g., bladder infections or structural abnormalities) can also contribute. Nocturnal enuresis has also led to a series of sleep studies (e.g., in which stage of sleep has been related to enuretic events). Correlations with psychosocial stressors suggest an important role for psychological factors to contribute, and such theories exist but have proven difficult to experimentally verify. The interrelationships of behavioral and developmental difficulties with enuresis have been difficult to disentangle, although it does appear that, at least in some cases, a strong genetic component is present, and efforts to identify specific genes potentially involved are underway.

Differential Diagnosis and Assessment

Urinalysis is an obvious first step in evaluation of enuresis (e.g., to rule out urinary tract infection as a cause). In general, invasive laboratory studies do not have a particularly high yield and would not be indicated unless other indications were present. Children who have problems in both the nighttime 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 time, enuresis may arise after other medical problems (e.g., hyperthyroidism), although this is infrequent. A physical examination should look for potentially treatable underlying conditions. Associations with other factors (e.g., nocturnal enuresis that occurs after administration of a new medication) should be explored as relevant.

Treatment

Historically, two rather different treatments have been used with greatest success in treatment of enuresis: behavioral and pharmacological approaches. Behavioral treatments have a long history and have the important advantage of avoiding potential side effects of pharmacological ones. It is important to note that there is some potential for the parents or the child to view use of behavioral techniques as somehow suggesting that the condition is, at least in part, volitional. The bell and pad method has a long history of use and, essentially, combines
principles of both classical and operant condition in helping the child learn to avoid nighttime awakening. In this approach, the child sleeps on a pad that, when wet, rings a bell, arousing the child from sleep. This method has a reasonably high success rate (as many as two-thirds of children will respond), and response is maintained in many (>50% of cases) after the treatment is discontinued. Lower levels of family stress and an absence of other psychiatric problems in the child are associated with higher success rates. Some studies have investigated the impact of bladder capacity and response to this treatment. New behavioral approaches continue to be developed (e.g., using an alarm clock to wake the child at a predetermined time during the night or using an ultrasonic monitor attached to the abdomen to awaken the child when a specific bladder volume has been reached).

These treatments have also been combined with pharmacological ones. Drug treatments include the use of impramine and, more recently, desmopressin acetate (DDAVP). The tricyclic antidepressant impramine has been used for treatment of nighttime bed wetting for many decades, and a series of double-blind studies have confirmed its usefulness. It is usual to begin with 25 mg and then gradually increase it, adding 25 mg every week. Usual effective doses are between 75 and 125 mg a day. Some children respond to smaller doses. The maximum dose should be no more than 5 mg/kg/day. Electrocardiography should be obtained at baseline, and continued monitoring is needed at doses greater than 3.5 mg/kg. Given the high rate of remission, regular attempts should be made to evaluate the continued need for medication (e.g., a slow taper every 3 to 4 months allows the medication to be increased if wetting returns). Some children have a transient response to impramine even when the dose is increased. For these individuals, the periodic use of the agent (e.g., at summer camp) may be an option. Given the potential for side effects of this agent, careful education of child and parents is needed (e.g., to avoid a child’s taking “extra” medication). There appears to be some correlation between blood level and therapeutic effect, although as a practical matter, side effects such as dry mouth may be a more practical way to be sure that an adequate level has been obtained. The mechanism of action of this agent remains unclear, but it does not simply appear to relate to its antidepressant properties.

Recent interest has centered on the use of DDAVP, a synthetic analogue of the pituitary hormone 8-arginine vasopressin (ADH), which affects renal water conservation. A large number of patients have been enrolled in a series of well-controlled studies. Most of the patients had not responded to previous treatments, and most did respond to DDAVP. The mechanism of action is presumed to be decreased output. Wetting typically returns if the medication is discontinued. The usual dose is 200 to 400 µg given orally (a nasal spray was previously available, but the Food and Drug Administration has recommended against its use for enuresis); there is some suggestion that even lower dose may be effective. The most frequent side effects include headache, flushing, and abdominal pain. The medication should not be used to treat enuresis resulting from a specific medical condition causing increased urination. The most serious complications include hyponatremia and hyponatremic seizures with intranasal use of DDAVP.

In the past, psychotherapy was a mainstay of treatment but is now viewed as being indicated only for associated behavioral problems rather than having a primary impact on enuresis itself. Rates of spontaneous remission are high (as much as 20% of cases), complicating studies attempting to evaluate such interventions. On the other hand, development of enuresis after a stressful event or chronic familial conflict may provide an indication for psychotherapy. Similarly, negative self-image and self-esteem problems associated with nocturnal enuresis may be helped with psychotherapy. Table 18.1 summarizes factors to consider in treatment planning.

Outcome and Follow-up

As noted previously, spontaneous remission of bed wetting is common, particularly between the ages of 5 and 7 years and again in adolescence. In a given year, about 15% of children will experience a spontaneous remission of the condition. One major follow-up study compared
impramine, DDAVP, and the bell and pad method along with an observation-only group. Treatment was discontinued after 6 months, and patients were then followed. Six months later, 16% of the observation-only group members were continent compared with 16% of the imipramine-treated group, 10% of the DDAVP group, and 56% of the behavioral treatment group. Accordingly, behavioral treatments should be regarded as the first line of intervention with DDAVP and then imipramine should be made available for children who do not respond to the behavioral intervention.

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