Desmopressin resistant enuresis: Pathogenetic and therapeutic considerations

Purpose: We tested the role of the bladder in the pathogenesis of desmopres sin resistant enuresis by evaluating the influence of urine production on t he timing of the enuretic event and the response to anticholinergic medicat ion. Materials and Methods: We gave 33 children with monosymptomatic nocturnal a nuresis 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-bli nd crossover fashion. The time of enuresis or nocturia was documented. All 9 children who had at least 1 dry treatment period during the randomized po rtion of the study then received open label treatment with 0.8 mg. desmopre ssin. 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 hour s during the nights with placebo, and 0.4 and 0.8 mg. desmopressin, respect ively (p = 0.12). Of the 9 children subsequently treated with 0.8 mg. desmo pressin 5 became completely dry. Of the remaining 28 children given anticho linergic treatment 20 responded. Conclusions: Antidiuresis does not delay the enuretic event in children wit h 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.