Increased Nocturnal Blood Pressure in Enuretic Children With Polyuria

Autonomic nervous system dysregulation in children with monosymptomatic nocturnal enuresis

AIM

To investigate the role of autonomic nervous system in subpopulations of children with enuresis.

METHODS

We included 35 children with enuresis, divided in children with (17) and without nocturnal polyuria (18) and 43 healthy controls. For all participants hormones and neurotransmitters were measured. Patients and controls wore a sleep tracker device and children with enuresis underwent a 24 h blood pressure monitoring, nocturnal urine output measurement and uroflowmetry.

RESULTS

Children with enuresis had lower than controls copeptin and aldosterone, with the latter being more prominent in patients without nocturnal polyuria. Dopamine was lower in patients without nocturnal polyuria compared with patients with nocturnal polyuria. Children without polyuria experienced episodes only during NREM sleep, whereas in children with polyuria episodes occurred in both REM and NREM sleep. Children with enuresis experienced a non-dipping phenomenon during sleep which was more prominent in the group without polyuria.

CONCLUSION

In patients with nocturnal polyuria, nocturnal enuresis is associated with sympathetic hyperactivity which results in pressure polyuria and significantly lower systolic dipping during sleep. On the contrary, in children without nocturnal polyuria, it is mostly associated with bladder overactivity due to parasympathetic overstimulation as demonstrated by the NREM-related enuretic episodes and the lower aldosterone and dopamine levels.

Nocturia and Blood Pressure Elevation in Adolescents

Nocturia has been increasingly recognized as a manifestation of various non-urological conditions including hypertension. In adults, blood pressure (BP) elevation has been identified as a robust correlate of nocturia, but such a relationship has not been studied in pediatric populations where nocturia is often attributed to hormonal, sleep, physiological or psychological disorders. Accordingly, this study aimed to determine the relationship between nocturia and BP elevation in adolescents. We prospectively studied 100 patients, aged 10-18 years, recruited from pediatric clinics at our institution. Nocturia (defined as ≥ 1 voids on voiding diary analysis) was present in 45% of the study sample (range: 1-4 voids/night). 37% of subjects self-reported awakening to urinate, and 34% of subjects had BP elevation according to age-dependent thresholds from current Pediatrics guidelines. On multivariate analyses, BP elevation was strongly associated with nocturia determined by both voiding diary (OR 26.2, 95% CI: 6.5, 106.0) and self-report. Conversely, nocturia was associated with increased odds of elevated BP by diary (26.3, 95% CI: 6.5, 106.4) and self-report (OR 8.1, 95% CI: 3.2, 20.5). In conclusion, nocturia appears to be common and is strongly associated with BP elevation in adolescents. These findings suggest that eliciting a history of nocturia holds promise as a simple method of identifying adolescents at risk for hypertension.

Differences in the urinary metabolome and proteome between wet and dry nights in children with monosymptomatic nocturnal enuresis and nocturnal polyuria

BACKGROUND

Nocturnal enuresis (NE) is a common disease with multiple pathogenic mechanisms. This study aimed to compare levels of metabolites and proteins between wet and dry nights in urine samples from children with monosymptomatic NE (MNE).

METHODS

Ten boys with MNE and nocturnal polyuria (age: 7.6 ± 1.3 years) collected their total nighttime urine production during a wet and a dry night. Untargeted metabolomics and proteomics were performed on the urine samples by liquid chromatography coupled with high-mass accuracy tandem mass spectrometry (LC-MS/MS).

RESULTS

On wet nights, we found reduced urine osmolality (P = 0.025) and increased excretion of urinary potassium and sodium by a factor of, respectively, 2.1 (P = 0.038) and 1.9 (P = 0.19) compared with dry nights. LC-MS identified 59 metabolites and 84 proteins with significantly different levels between wet and dry nights (fold change (FC) < 0.67 or > 1.5, P < 0.05). Some compounds were validated by different methodologies. During wet nights, levels of compounds related to oxidative stress and blood pressure, including adrenalin, were increased. We found reduced levels of aquaporin-2 on wet nights. The FCs in the 59 metabolites were positively correlated to the FCs in the same metabolites identified in urine samples obtained during the evening preceding wet and dry nights.

CONCLUSIONS

Oxidative stress, which in the literature has been associated with nocturia and disturbances in sleep, might be increased during wet nights in children with MNE. We further found evidence of increased sympathetic activity. The mechanisms related to having wet nights in children with MNE seem complex, and both free water and solute handling appear to be important. A higher resolution version of the Graphical abstract is available as Supplementary information.

Non-dipping phenomenon effects in monosymptomatic nocturnal enuresis treatment?

BACKGROUND

Monosymptomatic enuresis nocturna patients are shown to have disrupted blood-pressure regulation accompanying polyuria. In our study, we aimed to research the desmopressin response of enuresis patients with blood-pressure regulation problems.

METHODS

The study included 175 patients, aged from 6-15 years, with a diagnosis of monosymptomatic enuresis nocturna. Before treatment, 24 h ambulatory blood-pressure monitoring (ABPM) was used to identify 52 non-dipper patients and 73 patients with normal results. The responses to desmopressin treatment and clinical and demographic characteristics affecting response were compared.

RESULTS

The response to desmopressin treatment was found to be significantly low in the patients who were non-dippers on 24 h ABPM before treatment compared to those with normal ABPM results (P < 0.05). Similarly, the waking problems in the non-dipper group were found to be high by a significant degree (P < 0.05). In the non-dipper group, the systolic non-dipping rate was higher.

CONCLUSIONS

Before desmopressin use, assessment of patients with a 24 h ABPM may be beneficial to select the method to be used for treatment.

Nocturnal enuresis in children: The role of arginine-vasopressin

Nocturnal enuresis is the involuntary pass of urine during sleep beyond the age of 5 years. It is a common condition in childhood and has an impact on the child's well-being. Research into the pathophysiology of the condition in the last decades has led to a paradigm shift, and enuresis is no longer considered a psychiatric disorder but rather a maturation defect with a somatic background. An excess urine production during sleep is a common finding in children with enuresis and disturbances in the circadian rhythm of arginine-vasopressin (AVP) is found in the majority of children with nocturnal polyuria. Children with enuresis and nocturnal polyuria lack the physiologic increase in AVP levels during sleep and treatment with the AVP analogue desmopressin can restore this rhythm and lead to dry nights. The reasons for this aberrant circadian AVP rhythm are not established. Furthermore, not all children with enuresis and nocturnal polyuria can be successfully treated with desmopressin suggesting that factors beyond renal water handling can be implicated such as natriuresis, hypercalciuria, and sleep-disordered breathing. The advances in the research of the genetic background of the condition may shed further light on the enuresis pathophysiology.

Sleep Monitoring of Children With Nocturnal Enuresis: A Narrative Review

The purpose of this article is to provide a succinct summary of the sleep monitoring efforts that have been used in nocturnal enuresis (NE) and an overview of the knowledge that has accrued. This is not intended to be a comprehensive review, but rather is intended to highlight how polysomnography (PSG), a common sleep detection tool, has contributed to our understanding of NE, as arousal disorder is considered to be one of the important mechanisms. The authors have organized this report by analysis and display of different ingredients of PSG, starting with comparing the electroencephalogram (EEG) of controls and the enuretic children and then moving to evaluation of respiratory patterns of NE and comorbid disease obstructive sleep apnea (OSA). In addition, the authors' goal is to better understand the mechanism of NE by integrating various levels of sleep monitoring; those sleep-related clinical scale scores for NE are presented to date. Finally, we propose further research of NE to explore the microstructure alterations via PSG combined with EEG-fMRI or to use novel technology like portable device internet and deep learning strategy.

A prospective study of examining physiological signals for estimating occurrence of nocturnal enuresis

The nocturnal enuresis is challenging due to the increased social activities of the children. This disorder significantly bothers both the children and their parents in psychological, behavioral, social, and financial manners. However, the primary treatments have limitations and further are not able to completely cure the disorder. In order to reduce pain and burdens of patients and their parents, it is important to accurately estimate when the enuretic incident occurs in advance. For the estimation, we have comprehensively investigated various studies of the nocturnal enuresis in the diverse fields. Through the investigations, we have summarized four hypotheses of the physiological signals related to the enuretic moment. In order to conquer the nocturnal enuresis, we design a preliminary framework sensing and investigating the physiological signals with the sensors. Our synthesized approach to understand and estimate the moments of the enuretic incidents can establish a foothold to complete the promising prediction system.

The pathophysiology of monosymptomatic nocturnal enuresis with special emphasis on the circadian rhythm of renal physiology

Nocturnal polyuria in monosymptomatic nocturnal enuresis (MNE) has so far mainly been attributed to a disturbed circadian rhythm of renal water handling. Low vasopressin levels overnight correlate with absent maximal concentrating activity, resulting in an increased nocturnal diuresis with low urinary osmolality. Therefore, treatment with desmopressin is a rational choice. Unfortunately, 20 to 60 % of children with monosymptomatic enuresis are desmopressin-resistant. There is increasing evidence that other disturbed circadian rhythms might play a role in nocturnal polyuria. This review focuses on renal aspects in the pathophysiology of nocturnal polyuria in MNE, with special emphasis on circadian rhythms. Articles related to renal circadian rhythms and enuresis were searched through the PubMed library with the goal of providing a concise review.

CONCLUSION

Nocturnal polyuria can only partially be explained by blunted circadian rhythm of vasopressin secretion. Other alterations in the intrinsic renal circadian clock system also seem to be involved, especially in desmopressin-resistant enuresis.

WHAT IS KNOWN

• Disturbance in the circadian rhythm of arginine vasopressin secretion is related to nocturnal polyuria in children with enuresis. • Desmopressin is recommended as a treatment for monosymptomatic nocturnal enuresis, working as a vasopressin analogue acting on V2 receptors in the collecting ducts of the kidney. What is New: • Other renal circadian rhythms might play a role in nocturnal polyuria, especially in desmopressin-resistant case.

Sleep fragmentation and periodic limb movements in children with monosymptomatic nocturnal enuresis and polyuria

BACKGROUND

Children with nocturnal enuresis (NE) have been found to have sleep fragmentation and a high incidence of periodic limb movements in sleep (PLMS). This study explored the association of monosymptomatic NE and polyuria in relation to fluid intake, bladder volume, number of wet nights, and number of nights with polyuria to the frequency of PLMS and cortical arousals during sleep.

MATERIALS AND METHODS

Thirty children with monosymptomatic NE and polyuria were enrolled in the study. Enuretic parameters were determined by diaries, forced drinking, uroflow, and ultrasound examination. All subjects participated in one polysomnographic study. The number of cortical arousals and PLMS were compared with those recorded in a former pilot study which included only children with refractory NE.

RESULTS

Of the 30 children who participated in the study, the mean age was 10.43 ± 3.08 (range 6-16) years, and 23 were boys. The PLMS index was positively associated with the arousal index and the awakening index (p < 0.001). No significant association between the sleep and the enuretic parameters was found. Children with refractory NE showed a significantly higher PLMS index (p < 0.001).

CONCLUSIONS

We found that PLMS and cortical arousals in sleep were increased in children with monosymptomatic NE and polyuria, without a significant association with the enuretic parameters. These observations suggest the presence of a comorbid mechanism driven by a common, independent pacemaker. We hypothesize the autonomic system, its sympathetic branch, and the dopaminergic system as candidates for this pacemaker.

Sleep fragmentation and increased periodic limb movements are more common in children with nocturnal enuresis

AIM

To determine sleep fragmentation in children with nocturnal enuresis (NE).

METHODS

Paediatricians assessed NE parameters in children referred to an enuresis clinic. Control subjects, matched by age and gender and without incontinence or (un)treated NE, were recruited from the paediatric sleep clinic regardless of their sleep problem. Sleep was investigated by one overnight video-polysomnography in both groups.

RESULTS

The study group comprised 67 children with proven NE (50 boys and 17 girls between six and 16 years: 11.1 ± 2.8 SD). They were matched with 67 control subjects (47 boys and 20 girls aged between six and 16 years: 11.0 ± 2.9 SD). Children with NE had a higher incidence of periodic limb movements associated with cortical arousals in their sleep. They displayed significant higher periodic limb movement index, arousal index and awakening index than the control group.

CONCLUSION

Children with NE displayed higher sleep fragmentation and periodic limb movements in sleep than the control children with a possible sleep disorder without NE. The findings emphasise the central involvement of the pathophysiology of NE and the multifactorial nature of the condition.

Non-dipping phenomenon in children with monosymptomatic nocturnal enuresis

PURPOSE

Monosymptomatic nocturnal enuresis is a common disorder seen in childhood, and many factors play a role in its etiopathology to varying degrees. The aim of our study was to investigate the possible association between nocturnal enuresis and 24-h blood pressure profiles of enuretic children.

METHODS

A total of 45 children ranging in age from 6 to 15 years with monosymptomatic nocturnal enuresis and 22 age-matched healthy controls were enrolled in our study. The blood pressure measurement was made at 30-min intervals during a 24-h period via an ambulatory blood pressure measurement device. Both groups underwent medical tests that included a complete blood count, blood biochemistry profile, urinalysis and blood renin-aldosterone levels, and all study subjects received an abdominal ultrasound.

RESULTS

Statistically significant high nocturnal blood pressure levels were observed in our patients with monosymptomatic nocturnal enuresis compared with the control group (p < 0.05). The mean values of the day-to-night difference (dipping) in the systolic and diastolic blood pressure of the patients were significantly lower than those of control group (p < 0.05).

CONCLUSION

Nocturnal enuresis should not only be accepted as a urinary system disorder. Possible systemic causative factors have to be examined, especially in patients that are resistant to first-line therapy. Based on the results of our study, we deduce that one of the factors that plays a role in the pathogenesis of enuresis nocturna is a non-dipping blood pressure profile (the "non-dipping" phenomenon).

Reduced anti-diuretic response to desmopressin during wet nights in patients with monosymptomatic nocturnal enuresis

OBJECTIVE

To investigate why not all children with monosymptomatic nocturnal enuresis (MNE) treated with desmopressin give an adequate response.

MATERIALS AND METHODS

We included 114 children with MNE aged 5-15 years (9.8 ± 0.2 years) who experienced at least 1 wet night and more than 2 dry nights during desmopressin treatment. The patients made home recordings for 2 weeks as baseline and for 2-4 weeks of desmopressin titration. Nocturnal urine production during wet and dry nights, and maximum voided volumes (MVVs) were documented in all patients.

RESULTS

Sixty-four patients were desmopressin non-responders, 29 were either partial responders or responders, while 21 patients were full responders. Desmopressin reduced nocturnal urine production dramatically during dry nights compared with pre-treatment wet nights. Nocturnal urine production during desmopressin treatment was significantly greater during wet nights compared to dry nights (243 ± 9.32 vs 176 ± 5.31 ml, P < 0.001). There was a highly significant correlation between individual nocturnal urine output and MVV, and dry nights were characterized by nocturnal urine output/MVV ratios well below 1.0.

CONCLUSION

The anti-enuretic response to desmopressin seems to be dependent upon the degree of reduction in nocturnal urine production. Research on desmopressin bioavailability in children is needed.

Sleep deprivation induces excess diuresis and natriuresis in healthy children

Urine production is reduced at night, allowing undisturbed sleep. This study was undertaken to show the effect of sleep deprivation (SD) on urine production in healthy children. Special focus was on gender and children at an age where enuresis is still prominent. Twenty healthy children (10 girls) underwent two 24-h studies, randomly assigned to either sleep or SD on the first study night. Diet and fluid intake were standardized. Blood samples were drawn every 4 h during daytime and every 2 h at night. Urine was fractionally collected. Blood pressure and heart rate were noninvasively monitored. Blood was analyzed for plasma antidiuretic hormone (AVP), atrial natriuretic peptide (ANP), angiotensin II, aldosterone, and renin. Urine was analyzed for aquaporin-2 and PGE2. Successful SD was achieved in all participants with a minimum of 4 h 50 min, and full-night SD was obtained in 50% of the participants. During SD, both boys and girls produced markedly larger amounts of urine than during normal sleep (477 ± 145 vs. 291 ± 86 ml, P < 0.01). SD increased urinary excretion of sodium (0.17 ± 0.05 vs. 0.10 ± 0.03 mmol·kg−1·h−1) whereas solute-free water reabsorption remained unchanged. SD induced a significant fall in nighttime plasma AVP ( P < 0.01), renin ( P < 0.05), angiotensin II ( P < 0.001), and aldosterone ( P < 0.05) whereas plasma ANP levels remained uninfluenced ( P = 0.807). Nighttime blood pressure and heart rate were significantly higher during SD (mean arterial pressure: 78.5 ± 8.0 vs. 74.7 ± 8.7 mmHg, P < 0.001). SD leads to natriuresis and excess diuresis in healthy children. The underlying mechanism could be a reduced nighttime dip in blood pressure and a decrease in renin-angiotensin-aldosterone system levels during sleep deprivation.

Excess diuresis and natriuresis during acute sleep deprivation in healthy adults

The transition from wakefulness to sleep is associated with a pronounced decline in diuresis, a necessary physiological process that allows uninterrupted sleep. The aim of this study was to assess the effect of acute sleep deprivation (SD) on urine output and renal water, sodium, and solute handling in healthy young volunteers. Twenty young adults (10 male) were recruited for two 24-h studies under standardized dietary conditions. During one of the two admissions, subjects were deprived of sleep. Urine output, electrolyte excretions, and osmolar excretions were calculated. Activated renin, angiotensin II, aldosterone, arginine vasopressin, and atrial natriuretic peptide were measured in plasma, whereas prostaglandin E2 and melatonin were measured in urine. SD markedly increased the diuresis and led to excess renal sodium excretion. The effect was more pronounced in men who shared significantly higher diuresis levels during SD compared with women. Renal water handling and arginine vasopressin levels remained unaltered during SD, but the circadian rhythm of the hormones of the renin-angiotensin-aldosterone system was significantly affected. Urinary melatonin and prostaglandin E2 excretion levels were comparable between SD and baseline night. Hemodynamic changes were characterized by the attenuation of nocturnal blood pressure dipping and an increase in creatinine clearance. Acute deprivation of sleep induces natriuresis and osmotic diuresis, leading to excess nocturnal urine production, especially in men. Hemodynamic changes during SD may, through renal and hormonal processes, be responsible for these observations. Sleep architecture disturbances should be considered in clinical settings with nocturnal polyuria such as enuresis in children and nocturia in adults.