Association between urinary electrolyte level and detrusor overactivity in children with primary monosymptomatic nocturnal enuresis

Feng Z1, Wu G2, Shao S3, Liu K4, Wen J1

Research Type

Clinical

Abstract Category

Paediatrics

Abstract 539
Open Discussion ePosters
Scientific Open Discussion Session 105
Friday 19th September 2025
13:00 - 13:05 (ePoster Station 2)
Exhibition
Nocturnal Enuresis Detrusor Overactivity Pediatrics Voiding Dysfunction Retrospective Study
1. Henan Joint International Paediatric Urodynamic Laboratory, Department Urology, First Affiliated Hospital of Zhengzhou University, 2. Department of Urology, Children Hospital of Dongguan City, 3. Department of Pediatric Surgery, The First Affiliated Hospital of Xinxiang Medical University, 4. Department of Pediatric Surgery, The First Affiliated Hospial of Henan University of Science and Technology
Presenter
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Abstract

Hypothesis / aims of study
This is an original study that aims to investigate the correlation between urinary electrolyte levels and detrusor overactivity (DO) in children with primary monosymptomatic nocturnal enuresis (PMNE).
Study design, materials and methods
In this case control study, a retrospective analysis was performed on 60 PMNE children aged 5-12 years who were admitted to the First Affiliated Hospital of Zhengzhou University from February 2015 to January 2020. According to ambulatory urodynamic monitoring (AUM), 36 patients were categorized into nocturnal DO group [(19 males and 17 females, mean age(9.4±2.1) years, mean body mass index (BMI)(18.90±2.66) kg/m 2], and 24 patients, non-nocturnal DO group [16 males and 8 females, mean age(9.0±1.9) years, mean BMI(18.85±2.50) kg/m 2]. Daytime and nighttime urine volume and average urine electrolyte levels were measured. t-test, Chi-square test or Mann-Whitney U test were used for comparison between groups. Spearman rating coefficient was used to evaluate the correlation between average electrolyte level and maximum detrusor pressure during nighttime bladder storage.
Results
There were no statistically significant differences in age, gender ratio, and BMI between the two groups (all P>0.05).The nocturnal urine volume [0.291(0.194, 0.408) L] and the frequency of nocturnal polyuria (33.0%) in the nocturnal DO group were significantly lower than those [0.420 (0.298, 0.673) L and 62.5%](all P<0.05) in the non-nocturnal DO group.The levels of nocturnal urine sodium [(181.13±102.39) mmol/L], calcium [(3.68±2.44) mmol/L], and chloride [(147.89±57.21) mmol/L] in the nocturnal DO group were significantly higher than those [levels of nocturnal urine sodium [(132.15±67.42) mmol/L], calcium [(1.98±2.07) mmol/L], and chloride [(110.95±54.27) mmol/L] in the non-nocturnal DO group (all P<0.05).However, there was no statistically significant difference in the level of nocturnal urine potassium between the two groups ( P>0.05).The levels of diurnal urine sodium, potassium, calcium, and chloride showed no statistically significant differences between the two groups (all P>0.05) (Table 1). The levels of nocturnal urine sodium [(181.13±102.39) mmol/L] and calcium [(3.68±2.44) mmol/L] in the nocturnal DO group were significantly higher than the levels of diurnal urine sodium [(132.48±79.84) mmol/L] and calcium [(1.48±1.20) mmol/L](all P<0.05). However, there was no statistically significant difference in the levels of nocturnal urine potassium and chloride compared to diurnal levels (all P>0.05).In the non-nocturnal DO group, there were no statistically significant differences in the levels of diurnal and nocturnal urine sodium, potassium, calcium, and chloride (all P>0.05) (Table 2). Additionally, the level of nocturnal urine calcium in the nocturnal DO group was positively correlated with the maximum detrusor pressure during the bladder storage period ( r=0.501, P<0.05) (Figure 1).
Interpretation of results
This study revealed three key findings. First, the nocturnal DO group exhibited significantly lower nocturnal urine volume and reduced incidence of polyuria compared to the non-nocturnal DO group. Second, elevated nocturnal urinary electrolyte levels showed a positive association with detrusor overactivity. Third, higher urinary calcium levels correlated with increased maximum detrusor pressure during the storage phase. The mechanisms underlying these observations warrant further investigation.
Concluding message
The increased nocturnal urine sodium, calcium, and chloride levels in children with PMNE may be one of the important reasons for the occurrence of nocturnal bladder dysfunction.
Figure 1 Figure 1.The correlation between the nocturnal urinary calcium level and the maximum detrusor pressure during nighttime urine storage in the DO group
Figure 2 Table 1.Comparison of average urine electrolyte levels and urine volume between the non-nocturnal DO group and the nocturnal DO group
Figure 3 Table 2.Comparison of daytime and nighttime urine electrolyte levels within the non-nocturnal DO group and the nocturnal DO group (mmol/L, mean ± SD)
Disclosures
Funding National Natural Science Foundation of China(82470807) Clinical Trial Yes Public Registry No RCT No Subjects Human Ethics Committee Ethics Committee of the First Affiliated Hospital of Zhengzhou University Helsinki Yes Informed Consent Yes
07/07/2025 12:32:15