Nocturnal Enuresis in Children
Bedwetting is common among children, but the relationship bedwetting, nighttime arousal, and obstructive sleep apnea (OSA) is unclear. A new study evaluated this relationship in children who underwent polysomnography.1
Consultant360 caught up with lead author Joanna E. MacLean, BSc(Hon), MD, PhD, who is an associate professor in the Division of Respiratory Medicine and Department of Pediatrics at the University of Alberta in Canada. Here are her answers to our burning questions.
CONSULTANT360: Can you give us an overview of your study and what you found?
Dr MacLean: In this study, we wanted to understand why children have nocturnal enuresis and how this relates to obstructive sleep apnea, which is risk factor for nocturnal enuresis.
The results showed that children with nocturnal enuresis have more disruption in their breathing during sleep, including higher variability in oxygen and carbon dioxide, and blunting of the expected decrease in heart rate across sleep.
We saw no difference in the ability to concentrate urine or blood pressure during sleep. Put together, these findings show that, rather than being related to abnormalities in urine concentrating or high blood pressure, nocturnal enuresis is related to impairments in autonomic control.
C360: Did any of these findings surprise you?
Dr MacLean: We did not see differences in arousal from sleep or markers of sleep disruption. This was surprising, as the only difference between children with nocturnal enuresis and nocturia is awakening to get up to void.
We did see that despite more disruption in oxygen and carbon dioxide parameters, arousal frequency was similar. This could be the result of altered sensing or set points for oxygen and carbon dioxide, so we could not say that this was evidence of a higher arousal threshold for children with nocturnal enuresis.
C360: How will these findings affect clinical practice?
Dr MacLean: Our work highlights a likely common pathway between nocturnal enuresis and OSA with mechanisms related to sleep continuity as important candidates. This means that emphasizing the importance of sleep hygiene in children with nocturnal enuresis may be beneficial for at least some children. When sleep patterns are irregular, or when there is insufficient sleep, nocturnal enuresis may take longer to resolve than when there is regular, sufficient sleep.
Fluid restriction is a common recommendation for children with nocturnal enuresis; our data supports that this likely is not going to be effective. Encouraging good hydration and regular voiding during the day without excess fluids prior to bedtime is likely a better approach.
We know that children with OSA are more likely to have nocturnal enuresis, and nocturnal enuresis does improve in some children after treatment of obstructive sleep apnea. Those who do not respond may have an underlying difference in autonomic control, but we do not know how to identify these children. Given this, we should be cautious in attributing nocturnal enuresis to OSA and waiting to consider other forms of management of nocturnal enuresis until after treatment of obstructive sleep apnea.
C360: What is the next step in your research?
Dr MacLean: This work helped us to identify candidate pathways that may link nocturnal enuresis and obstructive sleep apnea, which we plan to explore. Our methods for assessing arousal threshold were limited, so further work with specific measurements of arousal threshold is of interest.
C360: What knowledge gaps still exist in this area?
Dr MacLean: The mechanisms underlying nocturnal enuresis and OSA are not fully understood. Advancing our understanding of these mechanisms could lead to novel treatments for both conditions.
Reference:
- Bascom A, McMaster MA, Alexander RT, MacLean JE. Nocturnal enuresis in children is associated with differences in autonomic control. Sleep. 2019;42(3). https://doi.org/10.1093/sleep/zsy239.