Sleep Disordered Breathing in Infants with Prader-Willi Syndrome During the First 6 Weeks of Growth Hormone Therapy: A Pilot Study

Hypoventilation in patients with Prader-Willi syndrome across the pediatric age

OBJECTIVES

Few data on alveolar hypoventilation in Prader-Willi syndrome (PWS) are available and the respiratory follow-up of these patients is not standardized. The objectives of this study were to evaluate the prevalence of alveolar hypoventilation in children with PWS and identify potential risk factors.

STUDY DESIGN

This retrospective study included children with PWS recorded by polysomnography (PSG) with transcutaneous carbon dioxide pressure (PtcCO2) or end-tidal CO2 (ETCO2) measurements, between 2007 and 2021, in a tertiary hospital center. The primary outcome was the presence of alveolar hypoventilation defined as partial pressure of carbon dioxide (pCO2) ≥ 50 mmHg during ≥2% of total sleep time (TST) or more than five consecutive minutes.

RESULTS

Among the 57 included children (38 boys, median age 4.8 years, range 0.1-15.6, 60% treated with growth hormone [GH], 37% obese), 19 (33%) had moderate-to-severe obstructive sleep apnea syndrome (defined as obstructive apnea-hypopnea index ≥5/h) and 20 (35%) had hypoventilation. The median (range) pCO2 max was 49 mmHg (38-69). Among the children with hypoventilation, 25% were asymptomatic. Median age and GH treatment were significantly higher in children with hypoventilation compared to those without. There was no significant difference in terms of sex, BMI, obstructive or central apnea-hypopnea index between both groups.

CONCLUSION

The frequency of alveolar hypoventilation in children and adolescents with PWS is of concern and may increase with age and GH treatment. A regular screening by oximetry-capnography appears to be indicated whatever the sex, BMI, and rate of obstructive or central apneas.

The Impact of Growth Hormone Therapy on Sleep-Related Health Outcomes in Children with Prader-Willi Syndrome: A Review and Clinical Analysis

This literature review of growth hormone (GH) therapy and sleep-related health outcomes in children diagnosed with Prader-Willi syndrome (PWS) assembles evidence for the consequences of sleep deprivation and poor sleep quality: difficulty concentrating and learning at school, behavioral problems, diminished quality of life, and growth impairment. Sleep-disordered breathing (SDB) is another factor that impacts a child's well-being. We searched the electronic databases Medline PubMed Advanced Search Builder, Scopus, and Web of Science using MeSH terms and text words to retrieve articles on GH deficiency, recombinant human growth hormone (rhGH) therapy, sleep quality, SDB, and PWS in children. The censor date was April 2023. The initial search yielded 351 articles, 23 of which were analyzed for this review. The study findings suggest that while GH may have a role in regulating sleep, the relationship between GH treatment and sleep in patients with PWS is complex and influenced by GH dosage, patient age, and type and severity of respiratory disorders, among other factors. GH therapy can improve lung function, linear growth, and body composition in children with PWS; however, it can also trigger or worsen obstructive sleep apnea or hypoventilation in some. Long-term GH therapy may contribute to adenotonsillar hypertrophy and exacerbate sleep apnea in children with PWS. Finally, GH therapy can improve sleep quality in some patients but it can also cause or worsen SDB in others, leading to diminished sleep quality and overall quality of life. The current evidence suggests that the initial risk of worsening SDB may improve with long-term therapy. In conclusion, rhGH is the standard for managing patients with PWS. Nonetheless, its impact on respiratory function during sleep needs to be thoroughly evaluated. Polysomnography is advisable to assess the need for adenotonsillectomy before initiating rhGH therapy. Close monitoring of sleep disorders in patients with PWS receiving GH therapy is essential to ensure effective and safe treatment.

Preserved Sleep for the Same Level of Respiratory Disturbance in Children with Prader-Willi Syndrome

Debate remains as to how to balance the use of recombinant human growth hormone (rhGH) as an important treatment in Prader-Willi syndrome (PWS) with its potential role in obstructive sleep apnea. This single-center, retrospective study assessed differences in overnight polysomnography results between children with and without PWS and changes in respiratory parameters before and after the initiation of rhGH treatment in those with PWS. Compared with age-, sex-, and body-mass-index-matched controls (n = 87), children with PWS (n = 29) had longer total sleep time (434 ± 72 vs. 365 ± 116 min; p < 0.01), higher sleep efficiency (86 ± 7 vs. 78 ± 15%; p < 0.05), and lower arousal events (8.1 ± 4.5 vs. 13.0 ± 8.9 events/h; p < 0.05). Mean oxygen saturation was lower in PWS children (94.3 ± 6.0 vs. 96.0 ± 2.0%; p < 0.05), with no other differences in respiratory parameters between groups. Eleven children with PWS (38%) met the criteria for further analyses of the impact of rhGH; polysomnography parameters did not change with treatment. Compared with other children undergoing polysomnography, children with PWS had more favorable markers of sleep continuity and lower oxygen saturation for the same level of respiratory disturbance. rhGH administration was not associated with changes in respiratory parameters in PWS.

Diagnosis and management of sleep disorders in Prader-Willi syndrome

Clinical experience and a growing body of evidence suggest that sleep disturbances are common in people with Prader-Willi syndrome (PWS). PWS is a rare neuroendocrine disorder characterized by early hypotonia and feeding difficulties; developmental delays; endocrinopathies; and behavioral concerns, especially rigidity, anxiety, and behavioral outbursts. PWS is also characterized by decreased resting energy expenditure and transition to hyperphagia and obesity. We propose that, for many people with PWS, clinical diagnosis and management of sleep disorders is an unmet need. We present current information to suggest disordered sleep is a significant burden for individuals with PWS and often overlooked. While central and obstructive sleep apnea are more widely recognized in PWS, other sleep disorders have increasingly gained recognition, including hypersomnia, narcolepsy-like phenotypes, and insomnia. Sleep disorders can impact behavior, cognition, and quality of life and health for individuals with PWS. Our goal is to bring sleep disorders to the forefront of therapeutic intervention for patients with PWS. This paper presents a review of the literature and recommendations for clinical practice based on published research and our clinical experience as sleep specialists, geneticists, psychiatrists, pediatricians, otolaryngologists, and pulmonologists with extensive experience with this patient population. We recommend that management of sleep be considered an integral part of successful medical management of PWS. Further research concerning sleep problems in PWS is urgently needed to develop best practices and work toward a consensus statement for medical management to meet the needs of people with PWS.

CITATION

Duis J, Pullen LC, Picone M, et al. Diagnosis and management of sleep disorders in Prader-Willi syndrome. J Clin Sleep Med. 2022;18(6):1687-1696.

Obstructive events in children with Prader-Willi syndrome occur predominantly during rapid eye movement sleep

OBJECTIVE

Children with Prader-Willi syndrome (PWS) have a high prevalence of obstructive sleep apnea syndrome (OSAS). In most typically developing children with OSAS, more obstructive apneas and hypopneas occur during rapid eye movement (REM) than during non-REM (NREM) sleep. It was hypothesized that patients with PWS are even more prone to obstructive events in REM sleep than otherwise healthy subjects with OSAS.

METHODS

Polysomnographic data of patients with PWS and of typically developing children (controls) with OSAS (apnea-hypopnea index [AHI] > 1 episode/h) were analyzed. The two groups were compared regarding obstructive AHI (OAHI), OAHI during NREM sleep (OAHInrem), OAHI during REM sleep (OAHIrem), and the OAHIrem/OAHI ratio (outcome measures). The association between PWS diagnosis and OAHIrem/OAHI was adjusted for confounders using a general linear model.

RESULTS

Twelve children with PWS (median age 7.1 years [interquartile range 3.5, 12.4 years]) and 53 controls (6.5 years [3.9, 8.7 years]) were studied. Children with PWS and controls were similar regarding OAHI (p = 0.21) and OAHInrem (p = 0.76). However, subjects with PWS had higher OAHIrem (17.6 episodes/h [5.8, 25.8 episodes/h]) and OAHIrem/OAHI (2.3 [1.5, 3.2]) than controls (5 episodes/h [1.5, 8.1 episodes/h]; p = 0.002 and 1 [0.5, 2]; p = 0.003, respectively). The association between PWS diagnosis and higher OAHIrem/OAHI persisted after adjustment for age, gender, and obesity (p = 0.009).

CONCLUSION

In children with PWS, OAHI calculated for total sleep time does not reflect OSAS severity during REM sleep, which on average can be twice as high. Mild OSAS in patients with PWS demonstrated by polygraphy without sleep staging may correspond to a moderately-to-severely increased OAHIrem.

Low dose growth hormone treatment in infants and toddlers with Prader-Willi syndrome is comparable to higher dosage regimens

OBJECTIVE

Evaluate benefit and risk of low dose growth hormone treatment (GHT, 4.5mg/m²/week) in very young children with Prader-Willi Syndrome (PWS).

DESIGN

Prospective longitudinal clinical intervention.

METHODS

We evaluated 31 infants (aged 2-12months) and 42 toddlers (13-24months) from the PWS-OZGROW database for height, weight and BMI using the World Health Organization standard deviation scores (SDS_WHO) and PWS specific BMI (SDS_PWS), bone age, insulin-like growth factor 1 (IGF-I) levels and adverse events over 3years of GHT.

RESULTS

At commencement of GHT infants had a lower BMI SDS_WHO (-0.88 vs 0.40) than toddlers, while toddlers had a lower height SDS_WHO (-1.44 vs -2.09) (both P<0.05). All increased height SDS_WHO (2year delta height infants +1.26 SDS, toddlers+1.21 SDS), but infants normalised height sooner, achieving a height SDS of -0.56 within 1year, while toddlers achieved a height SDS of -0.88 in two years. BMI SDS_WHO increased, while BMI SDS_PWS decreased (both P<0.0001) and remained negative. The GHT response did not differ with gestation (preterm 23%) or genetic subtype (deletion vs maternal uniparental disomy). Bone age advancement paralleled chronological age. All children had low serum IGF-I at baseline which increased, but remained within the age-based reference range during GHT (for 81% in first year). Four children had spinal curvature at baseline; two improved, two progressed to a brace and two developed an abnormal curve over the observation period. Mild to severe central and/or obstructive sleep apnoea were observed in 40% of children prior to GHT initiation; 11% commenced GHT on positive airway pressure (PAP), oxygen or both. Eight children ceased GHT due to onset or worsening of sleep apnoea: 2 infants in the first few months and 6 children after 6-24months. Seven resumed GHT usually after adjusting PAP but five had adenotonsillectomy. One child ceased GHT temporarily due to respiratory illness. No other adverse events were reported. Two children substantially improved their breathing shortly after GHT initiation.

CONCLUSION

Initiation of GHT in infants with 4.5mg/m²/week was beneficial and comparable in terms of auxological response to a dose of 7mg/m²/week. Regular monitoring pre and post GH initiation assisted in early detection of adverse events. IGF-I levels increased with the lower dose but not excessively, which may lower potential long-term risks.

Respiratory Complications in Children with Prader Willi Syndrome

Prader Willi syndrome, resulting from the partial deletion or lack of expression of a region of genes on the paternal chromosome 15, has a number of phenotypic features which predispose affected patients to ventilatory problems. These include generalised hypotonia, abnormal arousal and ventilatory responses to hypoxia and hypercapnia, scoliosis and frequently, obesity. The spectrum of the resulting respiratory complications thus runs from sleep disordered breathing, to aspiration and respiratory functional impairment. While the use of growth hormone, in conjunction with multidisciplinary clinical management, is currently the cornerstone of clinical care of these patients, concerns have been raised following reports of sudden death shortly after growth hormone initiation. This review summarizes the respiratory complications commonly seen and draws together the published literature on the impact of growth hormone in relation to various respiratory parameters, aiming to provide the reader with the necessary information to manage these patients as safely as possible.

Sleep disordered breathing in patients with Prader-Willi syndrome: A multicenter study

OBJECTIVES

Sleep disordered breathing (SDB) is common in patients with Prader-Willi syndrome (PWS) and systematic screening is recommended, especially before growth hormone treatment. The aim of the study was to describe the baseline SDB and therapeutic interventions in a large cohort of patients.

STUDY DESIGN

Retrospective study.

SUBJECT SELECTION

Eighty-eight patients with PWS, median [interquartile range] age of 5.1 [1.0-14.5] years old (range 0.3-44.3), who were followed in three centers (France, Italy).

METHODOLOGY

Anthropometrics, polygraphy (PG), and gas exchange data were analyzed.

RESULTS

Median body mass index (BMI) was 20 [16-34] kg/m(2), BMI z-score for patients aged 2-20 years old was 2.1 [1.2-2.8] SD, mixed-obstructive apnea-hypopnea index (MOAHI) 1.8 [0.6-5.0] events/hr, and central apnea index (CAI) 0.1 [0.0-0.6] events/hr. Minimum pulse oximetry (SpO2) was 88 [84-91]%, percentage of time with SpO2 <90% 0.1 [0.0-1.0]%, and oxygen desaturation index 2 [1-4]/hr. An apnea-hypopnea index (AHI) ≥ 1.5 and ≥ 5 events/hr was observed in 53% of children and 41% of adults, respectively. No correlations were observed between MOAHI and anthropometrics data (age, BMI, BMI z-score), while MOAHI significantly correlated with SpO2 indexes. Age and BMI only weakly correlated with SpO2 indexes. Growth hormone could be initiated in 48 patients. Regarding post-PG therapy, 9 patients had upper airway surgery, and noninvasive CPAP/bilevel ventilation was started in 16 patients.

CONCLUSIONS

Patients with PWS exhibit a high prevalence of SDB. The lack of association between obesity and SDB leads to hypothesize that hypotonia and/or facial dysmorphic features may play a major role in the occurrence of SDB.

Velopharyngeal dysfunction in children with Prader-Willi syndrome after adenotonsillectomy

INTRODUCTION

Prader-Willi syndrome (PWS) is a rare genetic disorder with an incidence rate of 1 in 10,000-30,000. Patients with PWS typically have symptoms related to hypotonia, obesity, and hypothalamic dysfunction. A high rate of obstructive sleep apnea (OSA) is found among this population of patients. Adenotonsillectomy has been advocated as a first line approach for treatment of OSA in patients with PWS. Velopharyngeal dysfunction (VPD) is a known complication of adenotonsillectomy. VPD can also be present in patients with global hypotonia, such as those with PWS. The objective of this study is to review the occurrence of VPD in patients with PWS after adenotonsillectomy for OSA.

METHODS

A retrospective review was performed of all patients with PWS and OSA from a tertiary pediatric hospital between the years of 2002 and 2012. Pre- and post-operative sleep studies and sleep disordered breathing symptoms, post-operative VPD assessment by the speech-language pathologist (SLP), and VPD treatments were evaluated.

RESULTS

Eleven patients (five males and six females), fitting the inclusion criteria, were identified. The age of the patient at the initial otolaryngologic evaluation ranged from 2 to 9 years. All patients underwent adenotonsillectomy for sleep disordered breathing. Four patients were diagnosed with post-operative hypernasality after assessment by a speech-language pathologist. The hypernasality ranged from mild to moderately severe. Of the four patients with hypernasality, two were found to have structural issues requiring surgery (pharyngeal flap). Both of the surgical patients experienced significant improvement in their VPD after surgery. The remaining two patients were found to have articulation error patterns that were considered more developmental in nature and both responded to speech therapy. All patients, except one, had improvement in their polysomnogram or sleep symptoms after adenotonsillectomy. However, three patients continue to require continuous positive airway pressure at night.

CONCLUSION

Velopharyngeal dysfunction may occur after adenotonsillectomy in patients with Prader-Willi Syndrome. Families should be counseled of this risk and the potential need for operative intervention to correct it.

[Obstructive sleep apnea-hypopnea syndrome in children: beyond adenotonsillar hypertrophy]

The prevalence of obstructive sleep apnea-hypopnea syndrome in the general childhood population is 1-2% and the most common cause is adenotonsillar hypertrophy. However, beyond adenotonsillar hypertrophy, there are other highly prevalent causes of this syndrome in children. The causes are often multifactorial and include muscular hypotonia, dentofacial abnormalities, soft tissue hypertrophy of the airway, and neurological disorders). Collaboration between different specialties involved in the care of these children is essential, given the wide variability of conditions and how frequently different factors are involved in their genesis, as well as the different treatments to be applied. We carried out a wide literature review of other causes of obstructive sleep apnea-hypopnea syndrome in children, beyond adenotonsillar hypertrophy. We organised the prevalence of this syndrome in each pathology and the reasons that cause it, as well as their interactions and management, in a consistent manner.

Clinically important age-related differences in sleep related disordered breathing in infants and children with Prader-Willi Syndrome

Background

Sleep related disordered breathing (SDB) in pediatric Prader-Willi Syndrome is gaining increased attention due to the possible association of growth hormone therapy, SDB and sudden death. However data on the patterns of SDB and their management, particularly in infants in this population, is lacking.

Objective

The aim of this study was to 1) describe patterns of SDB in growth hormone naive infants with PWS and the management of these disorders in our institution 2) Compare the patterns of sleep disorders between infants and children with PWS.

Methods and Design

Polysomnograms of infants and children (0–18 years of age) with Prader-Willi Syndrome were reviewed. Age, sex, anthropometrics, sleep architecture, obstructive and central apnea indices and oxygen saturations were recorded. Data of infants with central sleep apnea treated with oxygen were analyzed to evaluate the efficacy of this treatment. The main outcome measures were obstructive and central apnea indices on a polysomnogram.

Results

Data of 44 patients, 23 under 2 years of age and 21 older children were included. Infants when compared with older children were more likely to experience central sleep apnea (43% vs. 5%; p = 0.003). In older children obstructive was significantly more prevalent than central sleep apnea. Supplemental oxygen was used to treat 9/23 infants with central sleep apnea. Oxygen therapy resulted in a significant decrease in the median central apnea index from 14 (5,68) to 1 (0,6; p = 0.008) events/hour and an improvement in the oxygen saturation nadir from 70% (52, 92) to 81% (64, 95; p = 0.080).

Conclusions

Central sleep apnea with associated oxygen desaturations is more prevalent in infants compared with older children with Prader-Willi Syndrome. Supplemental oxygen was efficacious in treating central sleep apnea in infants. Routine sleep surveillance for all children with Prader-Willi Syndrome and treatment with oxygen for central sleep apnea should be considered.

Genetic diseases: congenital central hypoventilation, Rett, and Prader-Willi syndromes

The present review summarizes current knowledge on three rare genetic disorders of respiratory control, congenital central hypoventilation syndrome (CCHS), Rett syndrome (RTT), and Prader-Willi syndrome (PWS). CCHS is characterized by lack of ventilatory chemosensitivity caused by PHOX2B gene abnormalities consisting mainly of alanine expansions. RTT is associated with episodes of tachypneic and irregular breathing intermixed with breathholds and apneas and is caused by mutations in the X-linked MECP2 gene encoding methyl-CpG-binding protein. PWS manifests as sleep-disordered breathing with apneas and episodes of hypoventilation and is caused by the loss of a group of paternally inherited genes on chromosome 15. CCHS is the most specific disorder of respiratory control, whereas the breathing disorders in RTT and PWS are components of a more general developmental disorder. The main clinical features of these three disorders are reviewed with special emphasis on the associated brain abnormalities. In all three syndromes, disease-causing genetic defects have been identified, allowing the development of genetically engineered mouse models. New directions for future therapies based on these models or, in some cases, on clinical experience are delineated. Studies of CCHS, RTT, and PWS extend our knowledge of the molecular and cellular aspects of respiratory rhythm generation and suggest possible pharmacological approaches to respiratory control disorders. This knowledge is relevant for the clinical management of many respiratory disorders that are far more prevalent than the rare diseases discussed here.

Prader-Willi syndrome and sleep-disordered breathing

Prader-Willi Syndrome is a complex neurogenetic disorder characterized by appetite dysregulation, obesity with decreased muscle mass and increased fat mass, behavioral problems, various endocrinopathies, and sleep and respiratory abnormalities. Respiratory issues include both central and obstructive sleep apnea, excessive daytime sleepiness, narcolepsy, and impaired ventilatory control. There is some controversy as to whether growth hormone treatment, which is the standard of care for patients with Prader-Willi Syndrome, exacerbates or ameliorates the sleep-disordered breathing issues associated with this syndrome. The natural history of sleep and breathing issues and the issues surrounding growth hormone treatment on sleep-disordered breathing are discussed.

Obstructive sleep apnea in infants

Obstructive sleep apnea in infants has a distinctive pathophysiology, natural history, and treatment compared with that of older children and adults. Infants have both anatomical and physiological predispositions toward airway obstruction and gas exchange abnormalities; including a superiorly placed larynx, increased chest wall compliance, ventilation-perfusion mismatching, and ventilatory control instability. Congenital abnormalities of the airway, such as laryngomalacia, hemangiomas, pyriform aperture stenosis, choanal atresia, and laryngeal webs, may also have adverse effects on airway patency. Additional exacerbating factors predisposing infants toward airway collapse include neck flexion, airway secretions, gastroesophageal reflux, and sleep deprivation. Obstructive sleep apnea in infants has been associated with failure to thrive, behavioral deficits, and sudden infant death. The proper interpretation of infant polysomnography requires an understanding of normative data related to gestation and postconceptual age for apnea, arousal, and oxygenation. Direct visualization of the upper airway is an important diagnostic modality in infants with obstructive apnea. Treatment options for infant obstructive sleep apnea are predicated on the underlying etiology, including supraglottoplasty for severe laryngomalacia, mandibular distraction for micrognathia, tonsillectomy and/or adenoidectomy, choanal atresia repair, and/or treatment of gastroesophageal reflux.

Prader-Willi syndrome: A primer for clinicians

The advent of sensitive genetic testing modalities for the diagnosis of Prader-Willi syndrome has helped to define not only the phenotypic features of the syndrome associated with the various genotypes but also to anticipate clinical and psychological problems that occur at each stage during the life span. With advances in hormone replacement therapy, particularly growth hormone children born in circumstances where therapy is available are expected to have an improved quality of life as compared to those born prior to growth hormone.

This manuscript was prepared as a primer for clinicians-to serve as a resource for those of you who care for children and adults with Prader-Willi syndrome on a daily basis in your practices. Appropriate and anticipatory interventions can make a difference.

Managing Prader-Willi syndrome in families: an embodied exploration

This paper aims to explore the management of a rare chromosome disorder, Prader-Willi syndrome (PWS), within families. It is particularly concerned with developing an understanding of the management of diet and other everyday practices affecting the body. People with PWS tend to experience poor muscle tone combined with food obsession. The level of control over diet needed to prevent obesity and related health complications is often lacking as individuals also experience various forms of learning disability, autistic spectrum disorders and behavioural problems. The findings are based on data from twenty qualitative case studies of English families with a young person with PWS. Analysis of management strategies highlights the centrality of embodied agency in shaping everyday practices and interactions. The significance and influence of biology within this process is particularly evident, as people with the genetic condition PWS experience embodiment and emotion in distinct ways and differently from non-PWS family members in the research sample. Focusing on the multidimensional nature of processes surrounding body management, the paper highlights three key management practices and explores how these practices are influenced by people with PWS and interpreted by family members. Three key practices are identified as: restricting access to food, keeping occupied, and use of routine. The study represents the first UK empirical sociological study of PWS and primarily adds an insight of family management of PWS to a medically dominated literature around the disorder. The findings can sensitise health and social care professionals to some potential issues for families managing PWS, and guide and develop appropriate interventions to support young people with PWS and their carers.