A POSSIBLE EXPLANATION OF WET AND DRY NIGHTS IN ENURETIC CHILDREN

Objective To clarify the relationship between nocturnal urine producti on and the occurrence of both wet and dry nights in patients with noct urnal enuresis and to estimate the effect on nocturnal urine productio n of treatment with the antidiuretic hormone desmopressin in a group o f enuretics with none or only a partial reduction in the number of wet nights in response to desmopressin treatment. Patients and methods Th e nocturnal urine production of 60 children with monosymptomatic noctu rnal enuresis was measured far 14 nights with no treatment (baseline) and for 14 nights with desmopressin treatment. Sixteen children having both wet and dry nights in the two periods were chosen for the subseq uent analysis. Results There was significantly less nocturnal urine pr oduction during desmopressin treatment (202 mL/night) than during the baseline period (279 mL/night; P < 0.001) and a corresponding decrease in the number of wet nights, from 10 during baseline to five during d esmopressin treatment. When expressed as mL/kg body weight per hour, t he urine production during baseline was 0.89 on wet and 0.625 on dry n ights (P < 0.001), and during desmopressin treatment was 0.716 and 0.5 35, respectively (P < 0.01). Conclusion In this group of enuretics the re was a clear reduction in the number of wet nights and in nocturnal urine production during desmopressin treatment, even though none becam e totally dry on desmopressin. There was a markedly higher nocturnal u rine production on wet nights during both the baseline period and duri ng desmopressin treatment. The higher urine production on wet nights c ould explain the enuretic episode, with urine production exceeding bla dder capacity.