Journal of Sleep Disorders: Treatment and CareISSN: 2325-9639

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Research Article, J Sleep Disor Treat Care Vol: 5 Issue: 2

Sleep Pattern in Primary Enuretic Children

Ibrahim MA1,2,*, Al-Hashel JY2,3, Rashad MH4
1Department of Neurology, Faculty of Medicine, Al-Azhar University, Egypt
2Department of Neurology, Ibn Sina hospital, Kuwait
3Department of Medicine, Faculty of Medicine, Health Sciences Centre, Kuwait University, Kuwait
4Department of clinical neurophysiology, Faculty of Medicine, Cairo University,Egypt
Corresponding author :Ibrahim MA
Department of Neurology, Faculty of Medicine, Al-Azhar University, Egypt
Tel: 0096566216516
E-mail: [email protected]
Received: March 03, 2015 Accepted: April 12, 2016 Published: April 17, 2016
Citation: Ibrahim MA, Al-Hashel JY, Rashad MH (2016) Sleep Pattern in Primary Enuretic Children. J Sleep Disor: Treat Care 5:2. doi:10.4172/2325-9639.1000172

Abstract

Objectives: Nocturnal enuresis is a common problem in children. A disturbance of sleep was suggested as a pathogenetic factor. Our aim is to compare sleep of primary nocturnal enuretic children with a group of matched controls.

Subjects and methods: This study was carried out on two groups; Patient group: included 20 patients; 13 males and 7 females with primary monosymptomatic nocturnal enuretic. Age range between 6-15 years and control group: included 20 apparently healthy subjects (10 males and 10 females) without any urological, neurological or other medical diseases. Nocturnal enuresis sheet, sleep questionnaire, Intelligence quotient and overnight polysomnography were applied.

Results: Nocturnal enuresis was common in males than females in patient group with no significant difference. Family history of NE was positive in 65% of cases. Excessive somnolence was significantly higher in patients than in control group. Arousal disorders and sleep wake transition disorders were common in patient group than control group with no significant difference between the two groups. There was a significant increase in stage 3 and 4 duration and a highly significant decrease in arousal index in patients in comparison to the control group. There was no statistically significant difference in sleep latency, REM latency and stage 1 & 2 duration in patients in comparison to control group. Enuretic events were distributed across the night and not related to specific sleep stage.

Conclusions: It seems that some children with primary nocturnal enuresis are deep sleepers. A high arousal threshold may be one of the pathogenetic factors underlying primary nocturnal enuresis.

Keywords: Primary nocturnal enuresis; Sleep disorders; Polysomnography; Arousal index; Bed wetting

Keywords

Primary nocturnal enuresis; Sleep disorders; Polysomnography; Arousal index; Bed wetting

Introduction

Nocturnal enuresis (NE) is the most common chronic problem in childhood next to allergic disorders. It is still perceived as a shameful condition and kept as a secret [1]. NE is classified according to the presence of other symptoms to: monosymptomatic and polysymptomatic and according to previous periods of dryness to primary and secondary [2].
Primary monosymptomatic nocturnal enuresis (PMNE) defined as bedwetting in individuals who have never been dry at night for an uninterrupted period of time of at least 6 months is estimated to occur in up to15% of 5-year-old with spontaneous resolution rate of approximately 15% per year with approximately 99% of children becoming dry by 15 years of age [3].
Studies indicate that nocturnal enuresis is best regarded as a group of conditions with different etiologies [2]. Nocturnal urinary continence is dependent on 3 factors; nocturnal urine production, nocturnal bladder function, and sleep and arousal mechanisms [4,5]. Sleep and arousal remain the least understood factors in the pathophysiology of enuresis. Countless numbers of parents have told physicians that their enuretic child is very difficult to arouse or rather, as the parents put it, “sleeps very deeply” [6].
Aim of this work is to comparing sleep of primary monosymptomatic nocturnal enuretic children with a group of matched controls.

Subjects and Methods

This study was carried out on two groups:
I-Patient group: included 20 patients with PMNE, thirteen were males (65%) and seven were females (35%) with a mean age of 10.9 ± 2.67 years fulfilling the following criteria: 1) Age: 6-15 years. 2) Primary monosymptomatic nocturnal enuresis; never been dry at night for an uninterrupted period of at least 6 months, at least once per month; wetting occurs only at night and no day time symptoms of wetting, urgency or polyuria. 3) Negative urine analysis & culture, and 4) Normal physical examination. The following groups were excluded: Patients with enuresis other than PMNE, patients with abnormal neurological examination, patients with IQ less than average; IQ < 90, and patients on medical treatment (Desmopressin, Imipramine) during the last month. Patients were recruited from the Pediatric, Urology, and Neurology outpatient clinics at AL-Hussein Hospital, Al Azhar University, Egypt.
II- Control group: included 20 apparently healthy subjects without nocturnal enuresis, ten were males (50%) and ten were females (50%) with a mean age of 10.15 ± 2.92 years. They were relatives of staff members working at AL-Hussein Hospital, Al Azhar University, Egypt and patients' relatives.
Nocturnal enuresis sheet, sleep questionnaire and overnight polysomnography (PSG) were applied. Polysomnographic recordings were performed using sleep screen which is compact portable device of Jaeger-Toennies (a product of VIASYS health care –Germany) with two Electroencephalogram (EEG) channels, Electro-oculogram (EOG), Submental and Anterior tibialis Electromyogram (EMG) and Electrocardiogram (ECG). Scoring of the sleep study was done manually according to the standard manual for staging normal sleep [7].
The sleep parameters which were obtained are: Total recording time (TRT), total sleep time (TST), sleep efficiency, sleep latency, REM sleep latency , total waking after sleep onset (WASO) in minutes, percentage of sleep stages 1, 2, 3 and stage 4 NREM sleep, stage REM sleep, arousal index, respiratory disturbance index (RDI), periodic limb movement index (PLMI) and heart rate (HR).
Bedwetting episodes were documented with a commercially available enuresis alarm (MALEM enuresis alarm. Model MO3. Designed and developed by Dr H. Malem; Malem Medical, 10 Willow Holt, Lowdham, England, UK).
Data obtained were tabulated and statistically analyzed. Significant result is considered if P < 0.05 and highly significant result is considered if P < 0.01.

Results

There was no significant difference between both groups in age or sex distribution. NE was common in males than females in patient group with no significant difference (P > 0.05) (Table 1). Thirteen patients had positive family history of nocturnal enuresis (65%). One parent of six of them was enuretic (46.2%), while both parents of the other seven were enuretics (53.8%). Regarding the number of enuretic episodes per week; seven patients voided from six to seven times (35%), eight from three to five times (40%) and five from one to two times (25 %).
Table 1: General characteristics of the patient and control groups.

Associated Sleep Disorders

Five patients had symptoms of difficult initiating and maintaining sleep; two patients felt anxious when falling asleep (10%), one patient waked up more than twice per night (5%) and two patients has difficulty getting to sleep at night (10%). While, seven controls has symptoms of difficult initiating and maintaining sleep; three were anxious when falling asleep (15%), two waked up more than twice per night (10%) and two has difficulty getting to sleep at night (10%) with no significant difference between the two groups (P > 0.05). Twelve patients (60%) suffered from excessive somnolence in the form of difficult to wake up in the morning. While three controls (15%) were difficult to wake up in the morning with highly significant difference between the two groups (P < 0.01). Eight patients (40%) suffered from arousal disorders. Three of them were confused on awaking (15%), three patients had night mares (15%) and two patients walked during sleep (10%). While three of the control group (15%) also had arousal disorders; two had night mares (10%) and one walked during sleep (5%). No significant difference between the two groups (P > 0.05).
Five patients (25%) had symptoms of sleep wake transition disorder. Three of them talked during sleep (15%) and two ground teeth during sleep (10%). While four controls (20%) had symptoms of sleep wake transition disorder; two talked during sleep (10%), one ground teeth during sleep (5%) and one jerks parts of the body while falling asleep (5%) with no significant difference between the two groups (P > 0.05) (Table 2).
Table 2: Sleep disorders in patient and control groups.

Polysomnography

There was no statistically significant difference between patient and control groups in; sleep latency, REM latency, TRT, TST, Sleep efficiency, and WASO (P > 0.05. There was no statistically significant difference between patient and control groups in stage 1 & 2 duration. There was a significant increase in stage 3 and 4 duration in patient group in comparison to the control group (P < 0.05). Also, there was a highly significant decrease in arousal index in patients in comparison to control group (P < 0.01). There was no statistically significant difference between patient and control groups in RDI or PLMI (P > 0.05) (Table 3).
Table 3: Polysomnographic data in patients and control groups.
Micturition latency defined as time between onset of sleep and enuretic event was 134 ± 49. The number of patients voided during sleep was eleven (55%). Five of them (45.5%) voided in stage 2, four (36.4%) in stage 3, 4 and two (18.1%) in stage REM (Table 4).
Table 4: Micturition latency and sleep stage of enuretic event in patient group.

Discussion

Although enuresis is one of the most common and distressing childhood sleep problems, there is still much disaccord as to how enuretic children sleep and what role sleep as such plays in the pathogenesis of enuresis [8].
Nocturnal enuresis is more common in males than in females which were noticed in many studies [9,10]. Monosymptomatic nocturnal enuresis is considered as a hereditary disorder. We reported that family history is positive in 65 % of patients. Norgaard et al. [11] found that when both parents were enuretic, their offspring had a 77 % risk of having nocturnal enuresis. The risk declined to 43 % when one parent was enuretic as a child and to 15 percent when neither parent was enuretic [11].
The frequency of enuretic episodes per week was variable among different studies. Clinical severity can be defined as: infrequent (one to two wetting episodes per week); moderately severe (three to five wetting episodes per week); and severe (six to seven wetting episodes per week) [12]
Regarding sleep disorders, in our study, the rate of occurrence of excessive somnolence was significantly higher in patient group than in control group. Numerous questionnaire studies have yielded that enuretic children are perceived to be exceedingly difficult to arouse [9,13,14]
There was no significant difference in the prevalence of parasomnias (arousal disorders and sleep wake transition disorders) between enuretic children and their nocturnally continent peers. Neveus et al. and Smedje et al. [9,15] reported the same results, but Mehlenbeck et al. [16] reported increased incidene of classic parasomnias such as somnabulism and confused arousals in enuretic group. This may be explained by the small number of patient group and varying inclusion criteria or presence of day time symptoms.
Polysomnographic data, in the present study showed no significant differences between the patient and control groups in; sleep latency, REM latency, TRT, TST, Sleep efficiency and WASO. This is in agreement with other investigators [8,9]. There was no significant difference between the patient and control groups in the duration of stage 1 and stage 2. On the other hand there was a significant increase in stage 3 and 4 (delta sleep) duration in patients than in the controls. Finley in his study, concluded that the polysomnographic differences were limited to a slight increase in delta sleep among bedwetters [17]. Also Inoue et al. [18] reported slight non significant increase in stage 4 among enuretic children. On the other hand Gillin et al. [19] gave more or less opposite results; enuretic subjects were found to exhibit less delta sleep than did dry children. This can be explained by that all subjects in Gillin et al. [19] study were boys and half of the enuretic children were described as mentally disturbed. Another study found no significant difference between dry and enuretic children as regard sleep staging. Neveus et al. [8]. also found no significant difference between dry and enuretic children except for the percentage of REM sleep which was somewhat low in enuretic children compared to normal controls [8,9]. The controversy can probably be solved by examining sub groups among the patients. There is an increasing awareness today that enuresis is a heterogenous entity, with the bladder function, urine production, and arousal mechanisms playing different pathogenic roles in different clinical subgroups of children [5].
Also in this study there was a highly significant decrease of arousal index in enuretic children in comparison to control group. This suggests a fact, that enuretic children are deep sleepers but the standard polysomnogram is of little use in telling whether a person is usually easy or difficult to arouse from sleep as two subjects may provide similar polysomnographic recordings and still have immensely different arousal thresholds [20].
The timing of the enuretic event and its possible link with sleep stages is a controversial field of study. In this study, the enuretic event occurred during any part of the night, with a mean time interval of about 134 ± 49 min. between sleep onset and the first involuntary voiding. This is in accordance with many studies [8,9,21] but contrary to others [22,23] who reported that the bladder is usually voided during the early hours of sleep. We found no link between the enuretic event and sleep stages and this is in agreement with other studies [18,8,22] and Conversely to others [9,21] who reported that enuretic events to be an almost exclusive non REM sleep phenomenon. This controversy probably stems from not recognizing the heterogeneity of the disorder. When the children are differentiated according to pathogenetic subtype, the results suggest that polyuric children usually void during the first third of the night, regardless of sleep stage, whereas children with detrusor-dependent enuresis may void during any part of the night and preferentially during non-REM sleep [24].

Conclusion

It seems that some children with primary nocturnal enuresis are deep sleepers compared with non enuretic children. A high arousal threshold may be one of the pathogenetic factors underlying primary nocturnal enuresis.

Acknowledgment

We acknowledge and appreciate the thoughtful comments and suggestions of, Tarek Awany, Amro Salem, Kamel Hewedy and Mahmoud Abdel Moaty, Professors of neurology, Faculty of Medicine, Al Azhar University, Egypt.

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