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Enuresis, or bedwetting, is described as episodes of urinary incontinence during sleep in children age 5 years and older. Monosymptomatic enuresis is incontinence in children without any other lower urinary tract symptoms and no history of bladder dysfunction.
Children with monosymptomatic enuresis have never achieved an acceptable period of nighttime dryness and are described as having primary enuresis. Another population of children with monosymptomatic enuresis includes those who have developed nocturnal incontinence after a dry period of at least six months. These children are described as having secondary enuresis.
The physiology of bladder control
Children learn bladder control at various ages during the potty-training years. Most children begin to stay dry during the night roughly at age 3 years. Continence and micturition involves a balance between the urethral sphincter closing and the detrusor muscle contracting. The proximal urethra and bladder are both located within the pelvis. Normally, urethral pressure exceeds the bladder pressure, which results in urine remaining in the bladder. As it increases or decreases, intra-abdominal pressure is transmitted to the urethra and bladder equally. This transmission leaves the pressure differentials unchanged, which results in continence maintenance.
Normal voiding and urine elimination is the result of changes in both of these pressure factors signaling the need to void. As the urethral pressure falls, the bladder pressure rises, thus contracting the detrusor muscle and opening the sphincters of the urethra for micturition.
A brief synopsis of the development of continence is as follows:
Infancy: voiding occurs frequently, reflexively, and without voluntary control.
Age 6 months to age 12 months: bladder capacity increases and voiding frequency decreases.
Age 1 year to age 2 years: conscious sensation and ability to feel fullness develops, able to postpone voiding briefly by contracting the sphincter
Age 2 years to age 3 years: volitional voiding develops; able to initiate, relax the pelvic floor, and inhibit voiding through the cerebral cortex
Age 4 years: bladder volume increases, able to remain dry for two to three hours and void five to eight times per day.
Assessing monosymptomatic enuresis
The clinician must consider all the potential causes for a child’s nocturnal enuresis. Occasionally the fullness sensation association and coordination between the bladder and the brain is not fully developed yet in some children. This lack of coordination tends to result in incontinence.
Bedwetting is not the child’s fault. No child consciously and purposely enjoys wetting his or her bed. In fact, nocturnal enuresis is common in families where one or the other parent experienced bedwetting as a child. If the child’s parent or parents were bedwetters, there is a strong correlation for inheritance. The pattern and trend of bedwetting typically follows an outgrowth of the nocturnal enuresis at roughly the same age as the afflicted parent.
This correlation is important to note, since it can be very reassuring to the child that the parent eventually outgrew bedwetting and therefore he or she will, too. Because primary monosymptomatic enuresis has a high rate of spontaneous resolution, it will be self-limiting.
It has been observed that bedwetting appears more often in boys. A study of more than 6,000 children found that roughly seven out of 100 boys and three out of 100 girls wet their beds at night a minimum of once a month.1 Boys are more frequent bedwetters because girls tend to mature faster and develop the brain-bladder control association more quickly. However, this theory is based on observation rather than data.
Nocturnal enuresis may also be related to the child’s bladder capacity. Some children hold a smaller volume of urine than what is considered normal for their age. To quickly estimate bladder capacity in milliliters, take the child’s age in years, add two, and multiply by 30. For example, a child aged 3 years has a bladder capacity of approximately 150 mL (i.e., [3 + 2] × 30=150).
A diminished level of vasopressin may be factorial in the child with primary monosymptomatic enuresis. Vasopressin is a normal hormone that reduces overnight urine production and concentrates the urine. A lack of ability to decrease the volume of urine and concentrate it can be another challenge in achieving nocturnal continence.
Finally, deep sleep further prevents the child from experiencing the fullness sensation of the bladder and awakening to go to the bathroom in a timely manner.
Physical, emotional, and developmental maturity
A child who shows no interest or concern with regard to his or her bedwetting is most likely not ready to take ownership of the behavior. The topic is best discussed with the parents after the initial assessment of the child. Likewise, a child who continues to have multiple daytime voiding accidents should work toward building dryness during the daytime before conquering the night.
According to guidelines from the National Institute for Health and Clinical Excellence, the prevalence of childhood primary enuresis diminishes with age. Prevalence at age 5 years is 16% and falls to 5% by age 10 years and 1% to 2% by age 15 years.2
It must be emphasized that enuresis is not a disease but rather a constellation of symptoms to be managed and changed through behavioral modification.3 To treat pediatric enuresis, the health-care provider needs to assess both the patient’s and the family’s readiness to take on the problem.
Does the child care that he or she wets the bed? Defined expectations must be discussed and established from the onset. Some parents may simply wish for reassurance that the enuresis is not caused by a physical abnormality. Such parents are not interested in commencing a long-term therapy.
If short-term dryness is a priority, the provider should emphasize that bedwetting is not the child’s fault and instruct the parents to not punish the child for bedwetting. Parents who are having difficulty coping with bedwetting or are exhibiting anger or blame toward the child may require additional support and referral.
The clinician should stress to the parents and patient that a prudent treatment program for enuresis involves several methods of therapy, used in sequence or in combination. The course of care may be prolonged; it may fail in the short term and is often associated with relapses.
The parents must be willing to participate and provide support. Guidance and direction will also be necessary in the school environment. Therapy should be goal-oriented, and follow-up must be consistent.
Plan of care
The typical plan of care starts at the initial appointment by assigning the child “homework.” This is done to set the tone for expectation and commitment toward the process. Homework usually is pared down to three manageable tasks that the child should fully incorporate into his or her routine before the next clinic visit.