Correspondence

Cortical Arousal in Children with Severe Enuresis

N Engl J Med 2008; 358:2414-2415May 29, 2008

Article

To the Editor:

Children with nocturnal enuresis are generally believed to be deep sleepers with impaired arousability.1 However, there are conflicting data with regard to sleep patterns in children with enuresis.2,3 Nocturnal enuresis often occurs with unstable bladder contractions in conjunction with polysomnographic changes from deep sleep to lighter sleep but without full awakening,4 suggesting that a relationship may exist between bladder overactivity and deranged arousability. We therefore investigated sleep patterns and cortical arousal in relation to bladder activity in children with severe enuresis.

Children with primary nocturnal enuresis that was severe and refractory (≥5 wet nights per week) and normal age-matched children without enuresis were prospectively recruited. Simultaneous nighttime polysomnography and continuous cystometry were conducted in the presence of a bedside observer. Unstable bladder contractions, episodes of nocturnal enuresis, and voided volume were assessed in all patients. Sleep stages and cortical arousals were analyzed by means of polysomnography.

Thirty-five patients (28 boys and 7 girls) with severe refractory nocturnal enuresis and 21 normal controls were evaluated. Among the patients with nocturnal enuresis, the mean age was 9.6 years (range, 6 to 14), and the mean number of wet nights per week was 6.1. All patients had markedly reduced nocturnal bladder capacity (mean, 44% of age-expected bladder capacity5) and unstable bladder contractions. Light non–rapid-eye-movement sleep occurred significantly more frequently, and deep non–rapid-eye-movement sleep and rapid-eye-movement sleep occurred significantly less frequently in patients with enuresis than in controls. Cortical arousals occurred more frequently (i.e., there was a higher arousal index) in patients with enuresis (Table 1Table 1Sleep Architecture and the Cortical Arousal Index in Children with Enuresis and Normal Controls.). (The cortical arousal index ranges from 1.12 to 12.48, with a higher score indicating frequent cortical arousals.) Cortical arousals and the arousal index were significantly and positively correlated with unstable bladder contractions (P<0.01).

With the use of a temperature probe (display accuracy, ±0.1°C) that was placed inside the urine-collection bag or diaper to detect episodes of enuresis,4 we could precisely record episodes of nocturnal enuresis and bladder activity without disrupting the patient's sleep. In contrast, previous studies depended on an alarm to detect nocturnal enuresis. Such alarms inevitably disrupt sleep after the first episode of enuresis; this disruption makes it difficult to evaluate the whole-night sleep pattern in children with severe enuresis who may have more than one episode of wetting per night.

Our results suggest an interaction between bladder overactivity and brain arousability (i.e., a “bladder–brain dialogue”) in severe nocturnal enuresis. We found that children with enuresis have more light sleep associated with frequent cortical arousals but an inability to awaken completely. We speculate that the transition from light sleep to complete awakening, as elicited by the arousal center, may be paradoxically suppressed by long-term overstimulation by signals from the bladder.

Chung K. Yeung, M.B., B.S., M.D.
Mei Diao, Ph.D.
Biji Sreedhar, Ph.D.
Chinese University of Hong Kong, Hong Kong, China
ckyeung@surgery.cuhk.edu.hk

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Citing Articles (11)

Citing Articles

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   Alexandra Bascom, Todd Penney, Mike Metcalfe, Aaron Knox, Manisha Witmans, Trina Uweira, Peter Douglas Metcalfe. (2011) High Risk of Sleep Disordered Breathing in the Enuresis Population. The Journal of Urology 186:4, 1710-1714
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   Bo Xiang, Sreedhar Biji, Ji Xian Liu, Winnie C. Chu, David K. Yeung, Chung Kwong Yeung. (2010) Functional Brainstem Changes in Response to Bladder Function Alteration Elicited by Surgical Reduction in Bladder Capacity: A Functional Magnetic Resonance Imaging Study. The Journal of Urology 184:5, 2186-2191
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   Akihiro Kanematsu, Kazuyoshi Johnin, Koji Yoshimura, Kazutoshi Okubo, Katsuya Aoki, Masato Watanabe, Kaoru Yoshino, Shiro Tanaka, Saburo Tanikaze, Osamu Ogawa. (2010) Objective Patterning of Uroflowmetry Curves in Children With Daytime and Nighttime Wetting. The Journal of Urology 184:4, 1674-1679
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   C Rahm, S Schulz-Juergensen, P Eggert. (2010) Effects of desmopressin on the sleep of children suffering from enuresis. Acta Paediatrica 99:7, 1037-1041
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   W.F. Bower, L. Swithinbank, T. de Jong, L.M.O. de Kort, D. Marschall-Kehrel. (2010) Assessment of non-neurogenic incontinence and lower urinary tract symptoms in adolescents and young adults. Neurourology and Urodynamics 29:5, 702-707
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   Johan Van de Walle, Charlotte Van Herzeele, Ann Raes. (2010) Is There Still a Role for Desmopressin in Children with Primary Monosymptomatic Nocturnal Enuresis?. Drug Safety 33:4, 261-271
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7. 7

   Karlien Dhondt, Ann Raes, Piet Hoebeke, Erik Van Laecke, Charlotte Van Herzeele, Johan Vande Walle. (2009) Abnormal Sleep Architecture and Refractory Nocturnal Enuresis. The Journal of Urology 182:4, 1961-1966
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8. 8

   Eliane G. Fonseca, Ana Paula N. Bordallo, Patrícia K. Garcia, Catya Munhoz, Cosme P. Silva. (2009) Lower Urinary Tract Symptoms in Enuretic and Nonenuretic Children. The Journal of Urology 182:4, 1978-1983
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9. 9

   Paul F Austin. (2009) New directions for the endocrine treatment of bedwetting. Expert Review of Endocrinology & Metabolism 4:5, 397-399
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10. 10

    Philip van Kerrebroeck, Jens Peter Nørgaard. (2009) Desmopressin for the treatment of primary nocturnal enuresis. Pediatric Health 3:4, 311-327
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11. 11

    Tryggve Nevéus. (2009) Diagnosis and management of nocturnal enuresis. Current Opinion in Pediatrics 21:2, 199-202
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