Desmopressin resistant enuresis: pathogenetic and therapeutic considerations.

PURPOSE

We tested the role of the bladder in the pathogenesis of desmopressin resistant enuresis by evaluating the influence of urine production on the timing of the enuretic event and the response to anticholinergic medication.

MATERIALS AND METHODS

We gave 33 children with monosymptomatic nocturnal enuresis resistant to the standard 0.4 mg. oral dose of desmopressin 0.4 and 0.8 mg. desmopressin and placebo tablets for 5 nights each in a double-blind crossover fashion. The time of enuresis or nocturia was documented. All 9 children who had at least 1 dry treatment period during the randomized portion of the study then received open label treatment with 0.8 mg. desmopressin. Nonresponders to this regimen and the remainder of the children were offered anticholinergic treatment.

RESULTS

Average time between bedtime and voiding was 5.0, 5.6 and 5.0 hours during the nights with placebo, and 0.4 and 0.8 mg. desmopressin, respectively (p = 0.12). Of the 9 children subsequently treated with 0.8 mg. desmopressin 5 became completely dry. Of the remaining 28 children given anticholinergic treatment 20 responded.

CONCLUSIONS

Antidiuresis does not delay the enuretic event in children with desmopressin resistant enuresis. This finding and the favorable response to anticholinergic medication favor the hypothesis that these children have nocturnal bladder instability. A subgroup of enuretic children responds to high but not normal doses of desmopressin.