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Nocturnal enuresis in children is associated with differences in autonomic control

  • Bascom A,
  • McMaster MA,
  • Alexander RT,
  • MacLean JE

Publication: Sleep, November 2018

DOI: 10.1093/sleep/zsy239

Study objectives:

To assess the relationship between urine osmolality, cardiovascular parameters, and nocturnal enuresis in a population of children undergoing polysomnographic assessment.

Methods:
This prospective observational study included consecutive children aged 5-17 years presenting for overnight polysomnography. Children were evaluated using continuous ambulatory blood pressure monitoring to assess heart rate and blood pressure. Urine samples were collected throughout the night to determine urine sodium excretion and osmolality. Comparisons of results were made between children with and without a history of nocturnal enuresis.

Results:
A total of 61 children were included for analysis; 13 had a history of nocturnal enuresis. Children with nocturnal enuresis had greater disruption in respiratory parameters including higher apnea-hypopnea index (mean difference 12.2±8.8 events/h, p<0.05), attributable to more central respiratory events (mean difference 5.4±4.9, p<0.05), and higher variability in both oxygen and carbon dioxide parameters compared to those without nocturnal enuresis. Sleep parameters, urine osmolality, and blood pressure did not differ between groups. Children with nocturnal enuresis showed an increase, rather than a decrease, in heart rate across the night (+5.4±19.1 vs. -6.0±14.8 beats/min, p < 0.05).

Conclusions:
Children with a history of nocturnal enuresis have greater respiratory abnormalities, no differences in urine osmolality or blood pressure, and loss of normal heart rate decrease across the night. This pattern suggests that autonomic control, rather than renal or hemodynamic abnormalities, may contribute to the pathophysiology of nocturnal enuresis.

Editorial comment from Prof. Konstantinos Kamperis

One of the cardinal pathophysiological factors of nocturnal enuresis is the excess urine production during sleep, termed nocturnal polyuria. New light has been shed into the etiology of nocturnal polyuria and it seems that factors beyond the antidiuretic hormone regulation are of importance. This study evaluates sleep by inpatient polysomnography as well as hemodynamics in both children with enuresis and continent children. According to the authors children with enuresis suffer greater abnormalities in their respiratory parameters and present with less intense decline in heart rate during sleep. Based on these findings the authors revisit the hypothesis of an autonomic disruption during sleep in children with enuretic. This could be the link between sleep disordered breathing and enuresis.