Vasopressin deficiency in primary nocturnal enuresis. Results of a controlled prospective study.

The lack of circadian rhythmicity of plasma arginine vasopressin (AVP) in primary nocturnal enuresis (PNE) in some children is known. The original test protocol is time-consuming and needs excellent compliance by children and parents. The goals of the presented study are the introduction of a simple screening test and the evaluation of the response of treatment using intranasal synthetic vasopressin. Fifty-five children (aged 8.2 +/- 3.1 years) with PNE and 15 children (aged 7.9 +/- 2.4 years) of a control group were investigated. Using a standardized protocol, AVP levels were measured by radioimmunoassay (RIA) under controlled water intake 3 times per day over a period of 72 h. Fourteen of 55 tested children (25.5%) with PNE had a significant decrease in nocturnal AVP when compared to the control group. We measured also an increased nocturnal urine volume and a lower urine osmolality in this enuretic group. Eight of 14 patients (57.1%) with plasma AVP deficiency (AVPD) also had bladder instability. Nine of 14 patients (64.3%) with AVPD with or without concomitant bladder instability were totally dry during desmopressin treatment, but only 2 (14.3%) remained dry after discontinuation of treatment. Our data suggest that nocturnal urine osmolality measurement may reflect AVPD and predict a positive treatment outcome.