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Reduction in nocturnal functional bladder capacity is a common factor in the pathogenesis of refractory nocturnal
C K Yeung1, F K Y Sit, L K C To
1Department of Surgery, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China. ckyeung@cuhk.edu.hk
Insights
Reduced nocturnal bladder capacity is a key factor in severe primary nocturnal enuresis (PNE) refractory to treatment. This impacts bladder storage, leading to bed-wetting even with normal daytime function.
Area of Science:
- Pediatric Urology
- Urodynamics
- Sleep Medicine
Background:
- Primary nocturnal enuresis (PNE) is common in children.
- Refractory PNE poses treatment challenges.
- Understanding nocturnal bladder function is crucial for effective management.
Purpose of the Study:
- To evaluate diurnal and nocturnal bladder reservoir function in children with refractory PNE.
- To identify underlying causes of treatment-resistant bed-wetting.
Main Methods:
- Ninety-five children with refractory PNE underwent detailed voiding frequency and volume recording.
- Daytime natural filling cystometry and nighttime continuous cystometry with EEG monitoring were performed.
- Patients were assessed for bladder instability and functional bladder capacity (FBC).
Main Results:
- Two patient groups emerged: Group A (35%) with normal daytime function but nocturnal detrusor instability and reduced FBC, and Group B (65%) with abnormal daytime urodynamics and reduced FBC day and night.
- Nocturnal polyuria was not observed in either group.
- Reduced nocturnal FBC was a significant finding in both groups.
Conclusions:
- A reduction in nocturnal functional bladder capacity (FBC) is a common factor in severe PNE refractory to treatment.
- This reduction can manifest as isolated nocturnal detrusor instability or as part of a broader voiding dysfunction.
- Addressing nocturnal FBC is likely key to managing treatment-resistant bed-wetting.
Objective:
To evaluate the diurnal and nocturnal bladder reservoir function in patients with refractory primary nocturnal enuresis (PNE).
Patients And Methods:
Ninety-five children (68 boys, 27 girls, mean age 9.3 years) with significant PNE (>/=3 wet nights/week) that was refractory to treatment with desmopressin +/- an enuretic alarm were assessed using detailed recording of voiding frequency and urinary volume both day and night, natural filling cystometry during the day and continuous cystometry with simultaneous electroencephalogram monitoring during sleep at night.
Results:
Patients could be broadly categorized into two groups. Group A comprised those with normal daytime urodynamics and functional bladder capacity (FBC) on detailed frequency-volume recording, but who developed marked detrusor instability associated with a significant reduction in nocturnal FBC and small-volume voiding only after sleep at night (33 patients, 35%); and group B, those with abnormal daytime urodynamics and with reduced FBC and small-volume voiding both day and night, but who somehow managed to mask their bladder symptoms during the day (62 patients, 65%). There was no evidence of nocturnal polyuria in either group and the ratios of day : night urinary output volumes for type A and type B patients were 1.48 and 1.99, respectively.
Conclusion:
A reduction in nocturnal FBC, either occurring only after sleep at night in association with the appearance of detrusor instability in patients with normal daytime urodynamics and FBC, or as a manifestation of occult voiding dysfunction or bladder outlet obstruction that affects the bladder reservoir function both day and night, appears to be a common factor and probably the main cause for a mismatch between nocturnal urine output and bladder storage capacity in patients with severe bed-wetting that was refractory to treatment.
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