Daily Functional Capacity of Urinary Bladder in Children with Primary Nocturnal Enuresis

Overview

A relative nocturnal polyuria is a characteristic manifestation of primary nocturnal enuresis. The efficiency oftreatment with desmopresin in 70% of patients confirms importance of this factor.Aims: The aim of the work was to find out in children, for the sake of rationalization of nocturnal enuresistherapy, if the therapeutic response to desmopresin may be predicted on the basis of determining daily functionalcapacity of urinary bladder.Patients and methods: The examinations were performed in 48 patients (age 10.2 ± 2.7 years). Patients withdaily enuresis, abnormal urinary pathways and/or constipation were excluded from the study. The daily functionalcapacity of urinary bladder was determined as a maximum value of diuresis after the administration of standardwater load, the value being expressed in absolute values (ml) as well as in percentage of age-related capacity ofurinary bladder, calculated according to Koff’s formula. After a two-week control period all the patients receivedtreatment with desmopressin (20
g intranasally in the evening) in the course of two weeks. In those subjects whodid not respond by at least 50% reduction in the frequency of enuresis episodes as compared with the control period(non-responders) the therapy continued with the administration of oxybutin (OXY) to DDAVP for the period ofsubsequent two weeks.Results: In 33 patients (65%) there was a desmopressin therapy-related reduction in the frequency of enuresisepisodes by more than 50% (so called responders). The weekly frequency of enuresis episodes decreased in theresponders from 4.1 ± 0.3 to 0.5 ± 0.1 (P < 0.001), whereas in the decrease in non-responders was less apparent(from 5.6 ± 0.4 to 3.8 ± 0.3, P < 0.05). The responders differed also in the fact that they had more enuresis episodesin the control period (P < 0.02), were older (P < 0.05) and their daily functional capacity of urinary bladder was significantly higher than in the non-responders (P < 0.01). A combined therapy (DDAVP plus OXY) causeda further significant reduction of the „wet nights“ in the non-responders (P < 0.02).Conclusions: The results indicate that the determination of daily functional capacity of urinary bladder maybe a useful guide for rational planning in the therapy of nocturnal enuresis in children. The demonstration of thelower daily functional capacity of urinary bladder in non-responders represents a stimulus for further studies withthe application of other methods aimed at adjustment of reservoir capacity of urinary bladder (e.g. stretching ofbladder, enuresis alarm).

Key words:
primary nocturnal enuresis, desmopressin, oxybutinin, urinary bladder capacity