Nocturnal Enuresis Treatment Thresholds
A 6-year-old boy with primary monosymptomatic nocturnal enuresis has been managed for 8 months with evening fluid restriction, a bedtime voiding routine, and a reward chart, but still wets 5 nights per week. He has no daytime urgency or incontinence and no constipation, and urinalysis is repeatedly negative. His mother asks when medication could be offered. At what age is oral desmopressin generally considered appropriate for isolated bedwetting?
- A.5 years
- B.6 years
- C.7 yearsCorrect
- D.8 years
Explanation
Management of monosymptomatic nocturnal enuresis is age-staged. Below 5 years only explanation and reassurance are given because wetting is developmentally normal. Between 5 and 7 years the emphasis is on conservative measures, namely balanced daytime fluid intake with restriction in the 2 hours before sleep, regular daytime voiding, treatment of constipation, and a reward system for agreed behaviors rather than for dry nights. From about 7 years onward, when conservative measures have failed and the wetting affects the child socially, active therapy is offered, with the enuresis alarm having the best long-term cure rate and oral desmopressin used when rapid or short-term dryness is needed such as for camps and sleepovers, or when an alarm is impractical for the family. Desmopressin acts as a vasopressin analogue that reduces overnight urine volume, works quickly, but has a high relapse rate on withdrawal and requires fluid restriction from 1 hour before until 8 hours after the dose to prevent hyponatremia and seizures. The alarm conditions the child to wake to the sensation of a full bladder and needs several weeks of consistent use before benefit is judged. Anticholinergics such as oxybutynin are reserved for children with overactive bladder features, and tricyclics such as imipramine are third line because of cardiotoxicity in overdose. Persisting failure or emergence of daytime symptoms should prompt reassessment for constipation, urinary infection, and diabetes.
Why each option
- A.
- At 5 years the diagnosis can be made but management is conservative advice and reassurance, not medication.
- B.
- At 6 years conservative and behavioral approaches remain the mainstay; drug therapy is not routinely started.
- C.
- Correct. From about 7 years an alarm or oral desmopressin is offered when conservative measures have failed.
- D.
- Waiting until 8 years unnecessarily delays effective therapy in a child already failing conservative measures.
Reference: NICE Clinical Guideline CG111, Bedwetting in Under 19s, 2010
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