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Outgrowing Old Attitudes and Approaches to Nocturnal Enuresis

This report is based on medical evidence presented at sanctioned medical congress, from peer reviewed literature or opinion provided by a qualified healthcare practitioner. The consumption of the information contained within this report is intended for qualified Canadian healthcare practitioners only.

PRIORITY PRESS - Primary Care Today

Toronto, Ontario / May 7-9, 2009

Nocturnal enuresis, or frequent involuntary discharge of urine during sleep in children who have reached an age at which bladder control is expected, is a common and frequently persistent problem. It affects about one in 10 children aged 7 and about 1% of those aged 15. The propensity for nocturnal enuresis is genetically transmitted. If one parent experienced the problem, the likelihood of the offspring’s being affected is 44%; if two parents had enuresis, the likelihood increases to 77% (von Gontard et al. J Urol 2001;166(6):2438-43).

Children with nocturnal enuresis have important problems with self-esteem and relationships with others as their feelings of shame and embarrassment may prevent them from taking part in age-appropriate activities such as sleepovers, summer camp and travel. “It is an enormous problem for them. The only things that seem to be worse are parental fighting and divorce,” commented Dr. Norman Wolfish, Professor of Pediatrics, University of Ottawa, and pediatric nephrologist, Children’s Hospital of Eastern Ontario.

Parents tend to have a poor understanding of the causes of enuresis and while they want to be tolerant and supportive of the child, may express frustration and anger with ongoing bedwetting. This response, in turn, may aggravate the child’s own concern. Physicians seldom ask about bedwetting when interviewing patients and parents, and when consulted may believe that nocturnal enuresis is not serious enough an issue for intervention. Given that this problem can be a significant barrier to psychosocial maturation, treatment should be considered, Dr. Wolfish indicated.

Three Principal Factors

Nocturnal enuresis can be viewed as a triad of issues: excessive nighttime urine production, low functional capacity of the bladder (akin to that of an infant) and difficulty with arousal from sleep. Each of these can be mild to severe in degree. Under normal circumstances, during the overnight fast, a spike in antidiuretic hormone (ADH) directs the bladder to concentrate the urine in a smaller volume. Studies show that children with nocturnal enuresis may fail to show the ADH increase and typically produce almost as much urine at night as during the day. “So we have two problems with ADH. Either they are not secreting an appropriate amount or whatever they are secreting is ineffectual,” Dr. Wolfish indicated.

Bladder contractions only occur during periods of non-rapid eye movement (REM) sleep. In contrast with adults, in whom about 30% of the night is taken up by non-REM sleep, some 60% of a child’s nighttime sleep is non-REM. “They have a good likelihood of emptying their bladder if a contraction occurs,” he remarked.

Screening and Treatment Considerations

It is appropriate to screen patients for nocturnal enuresis when they present for a checkup or other office visit, Dr. Wolfish noted. If the child or parent acknowledges a bedwetting problem, a careful history and physical examination are usually sufficient to rule out secondary causes of polyuria. He added that contrary to popular belief, emotional upset such as the arrival of a sibling is seldom associated with secondary enuresis (bedwetting occurring after the child has been dry for a lengthy period). It is more likely that the child was not completely “dry” in the first place. Referral for ultrasound or other testing typically provides no diagnostic assistance.

The goals of therapy for patients with nocturnal enuresis are improvement of the bedwetting, its emotional impact on the child and the family dynamics. While mild cases may resolve rapidly, in severe cases small improvements may be important, Dr. Wolfish stated. For example, if a child who wears disposable underwear is still regularly soaking his pyjamas and the bed, even removal of the problem of excess laundry can be an enormous relief. Children who experience even a slight improvement overnight may feel better and may be able to take part in more activities. “The notion that you can improve a child’s self-esteem is probably the most important aspect of therapy… I am less interested in a child being ‘cured’ and more in his knowing [nocturnal enuresis] is not his fault and that one day it is going to get better,” Dr. Wolfish stressed.

Common-sense approaches include making sure the child does not overconsume liquids before bed (a mouthful of water is allowable as complete restriction may be seen as punishment), voiding before bedtime and sometimes getting the child up again to void before the parents retire for the night. “It is important to make sure the bladder does not reach the capacity that is going to cause it to contract,” Dr. Wolfish pointed out. Disposable underwear is preferred over diapers. Behavioural therapies such as rewarding the child or putting stars on a calendar after a dry night are largely ineffective, and a child who cannot achieve the goal may feel punished.

Medications that have been studied and employed in the past to manage nocturnal enuresis include anticholinergics and antidepressant agents. The former “should work, in theory” but have not been shown to be more effective than placebo, Dr. Wolfish observed. Tricyclic antidepressants achieve a reasonable improvement (response rate of approximately 40%) but are associated with a high relapse rate as well as important side effects including ventricular arrhythmias and even sudden death.

Preferred Approaches

The Canadian Pediatric Society recommends the use of desmopressin (the synthetic analogue of the ADH) and/or “wet alarms” that buzz to wake the child when moisture is detected by a sensor. Wet alarms are likely better for children at least 8 years of age than younger individuals, as non-REM sleep periods become shorter with age. An alarm that goes off but wakes everyone in the household except the child with enuresis is unlikely to be acceptable. The devices typically have high failure rates due to noncompliance and discontinuation of use.

In clinical studies, desmopressin has achieved efficacy rates of about 80% (Janknegt et al. J Urol 1997;157(2):513-7), and an improvement of 50% to 80% may be expected, depending on the severity of the child’s condition. One form of desmopressin, DDAVP, is available in tablets or in a formulation that melts when placed on or under the tongue. The latter is often preferred by children who may find it difficult to swallow tablets. In addition, Dr. Wolfish commented, the amount of water needed for the child to swallow tablets may promote increased urine output. The melting formulation has a duration of action of seven to 11 hours compared with up to 14 hours for the tablet. (A spray formulation, with a 20-hour duration of action, is contraindicated for nocturnal enuresis.) “The melt tends to be the more physiologic preparation...,” Dr. Wolfish commented. It supplements the ADH only during the child’s sleep period and wears off the next morning when the child starts to consume fluid.

Treatment with the melt is initiated at a starting dose of 120 µg. The dose may be increased to 240 µg and then to the maximum of 360 µg at three-day intervals if there is inadequate improvement in enuresis. (The melt is available in 120-µg and 240-µg doses for easier administration.) Parents must be advised that during desmopressin treatment, the child’s liquid intake should be restricted for one hour before and eight hours after administration (i.e., until morning). “How long to treat? Until the problem disappears… I like to give the drug so that the child is completely dry every single night for a period of three months. Then I taper the dose and see if some of the maturational mechanisms have taken over to ensure dryness,” Dr. Wolfish told delegates.

Reassurance May Not Be Enough

Although nocturnal enuresis is clearly related to slower than normal maturation of bladder control processes, reassurance that it can and will be outgrown is not always sufficient given the enormous impact the condition can have on the child and his or her family. Especially when bedwetting occurs two to three times per week or more, persists into the school years and/or is decreasing the child’s enjoyment of life, nocturnal enuresis should be evaluated and treated. “These kids should be looked after carefully,” Dr. Wolfish emphasized. To encourage compliance and success with therapy, the child should be involved in the selection of appropriate management strategies.

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