Evaluation of antidiuretic hormone before and after long-term treatment with desmopressin in a group of enuretic children.

OBJECTIVE: To determine the effect of long-term desmopressin therapy in enuretic patients on the levels of antidiuretic hormone (ADH) during and after the end of therapy. PATIENTS AND METHODS: The study comprised 25 outpatients (18 boys and seven girls) aged 8-12 years at the start of therapy and 12-16 years at the end. The morning (08.00 hours) plasma ADH level was determined before treatment (T0) with desmopressin and 2 years after (T1) ending the therapy. Seven of the 25 patients evaluated had monosymptomatic (simple enuresis, SE) and 18 had other symptoms (complex enuresis, CE). RESULTS: In the patients with SE, the mean (SD) duration of therapy was 305 (183) days and they were reevaluated 2.5 (0.67) years later. Of 18 patients with CE, eight were treated only with desmopressin for 204 (117) days. In 10 with an incomplete response after 30 days with only desmopressin, oxybutynin (5 mg twice daily) was added; the duration of their therapy was 255 (152) days and they were re-evaluated 3.9 (0.6) years later. The mean (SD) ADH level in those with SE and CE was 2.14 (0.93) ng/L and 2.53 (1.16) ng/L), respectively, both significantly lower (P < 0.001) than in controls, at 5.1 (1.6) ng/L. On re-evaluation at T1, there was a significant (P < 0.001) increase in ADH levels over those at T0 in both groups, at 5.2 (0.8) and 5.3 (1.9) ng/L, respectively. CONCLUSION: These results seem to confirm the role played by ADH in the pathophysiology of enuresis.