Pediatric obstructive sleep apnea: complications, management, and long-term outcomes

A mixed cell culture model for assessment of proliferation in tonsillar tissues from children with obstructive sleep apnea or recurrent tonsillitis

BACKGROUND

Recurrent infective tonsillitis (RI) and obstructive sleep apnea (OSA) are the major indications for adenotonsillectomy (T&A) in children. However, little is known on the determinants of lymphadenoid tissue proliferation in the pediatric upper airway.

OBJECTIVES

To develop an in vitro culture system allowing for assessment of tonsillar or adenoidal proliferation under basal or stimulated conditions.

METHODS

Tonsils surgically removed from pediatric patients with obstructive sleep apnea and recurrent tonsillitis during T&A, were dissociated using standard methods. Whole cell tonsillar cultures were either maintained in normal medium or stimulated with lipopolysaccharide (25 microg/mL) and concanavalin A (10 microg/mL) for 24 hours (stimulated conditions [STIM]). Cellular proliferation was evaluated by [3H]thymidine incorporation. In parallel, supernatants were collected after 48 hours, and concentration of cytokines was measured using standard enzyme-linked immunosorbent assay procedures.

RESULTS

Basal proliferative rates were increased in the OSA group (305.2 +/- 40.6 cpm; n = 31) compared to RI group (232.8 +/- 31.9 cpm; n = 26; P < .001). No significant differences in proliferative rates emerged after STIM between OSA and RI. Furthermore, basal TNF-alpha, IL-6, and IL-8 concentrations in the supernatant were increased in OSA-derived cultures compared to RI, but IL-8 was higher after STIM in RI, while IL-6 remained increased in OSA.

CONCLUSIONS

The proliferative rates and concentrations of inflammatory mediators in tonsillar cell cultures from children with OSA and RI suggest that lymphadenoid tissue proliferation in these two conditions may be regulated by different mechanisms. This novel method may allow for future development of specific therapeutic interventions aimed at curtailing and reversing tonsillar and adenoidal hypertrophy in children in a disease-specific manner.

Catecholamine alterations in pediatric obstructive sleep apnea: effect of obesity

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) elicits increased sympathetic activity in adults and increased urinary catecholamines. Moreover, urinary catecholamine excretion is altered in obese patients. We hypothesized that morning urine catecholamine levels would be correlated with the severity of obstructive sleep apnea and degree of obesity in children.

METHODS

Children referred to the pediatric sleep center for habitual snoring underwent overnight polysomnography, and the first morning voided urine sample was collected. Urinary concentrations of norepinephrine, epinephrine and dopamine were measured and corrected for creatinine levels. In a subset of children, blood samples were drawn and gene expression of catecholamine-relevant genes analyzed by quantitative real-time PCR.

RESULTS

One hundred fifty-nine children were recruited and completed the protocol. Children with OSA had significantly higher urinary norepinephrine and epinephrine levels, but not dopamine, compared to habitual snorers (norepinephrine: 40.1 +/- 24.7 ng/mg creatinine vs. 31.6 +/- 16.2 ng/mg creatinine, P < 0.01; epinephrine: 6.4 +/- 10.5 ng/mg vs. 4.5 +/- 0.5 ng/mg, P < 0.01). There was a positive correlation between norepinephrine and epinephrine values and polysomnographic indices, but no effect of obesity on catecholamine levels. In addition, expression of several of the major genes involved in synthesis and transport of catecholamines, as well as in selected receptors were compatible with increased bioavailability of catecholamines.

CONCLUSIONS

In children with OSA, morning urinary norepinephrine and epinephrine levels are significantly higher than those without OSA, and correlate with the severity of the disease. Gene expression patterns are in agreement with such findings. Urine catecholamine levels do not appear to be influenced by the presence of obesity. Thus, altered sympathetic activity in OSA patients appears to occur independently of the presence of obesity.

Severity assessment of obstructive sleep apnea syndrome (OSAS) in pediatric patients

OBJECTIVE

To assess obstructive sleep apnea syndrome (OSAS) severity among pediatric patients. Design. A retrospective review of charts and polysomnography (PSG) results.

MEASUREMENTS AND MAIN RESULTS

Apnea-hypopnea index (AHI) and the cumulative duration of sleep while O(2)SAT was <91% were determined in 389 patients with OSAS. Patients with AHI ranging <5, 5 to 15, 16 to 30, and >30, had mean lowest observed O(2)SAT values of 88% +/- 8%, 85% +/- 9%, 78% +/- 12%, and 69% +/- 13%, respectively. The patients spent a mean of 3.5% +/- 9.2 % of their sleep time with O(2)SAT < 91%. AHI values showed a poor linear correlation with the lowest measured O(2)SAT values. Body mass index percentiles showed no significant linear correlation with AHI values or with the lowest measured values of O(2)SAT.

CONCLUSION

Values of AHI cannot accurately predict severity of oxyhemoglobin desaturation in pediatric OSAS and vice versa. No significant correlation between body mass index percentiles and severity of OSAS was established.

Neurocognitive and behavioral impact of sleep disordered breathing in children

The consequences of poor quality and/or inadequate sleep in children and adolescents have become a major public health concern, and one in which pediatric health care professionals have become increasingly involved. In particular, insufficient and/or fragmented sleep resulting from primary sleep disorders such as obstructive sleep apnea (OSA), often compounded by the presence of comorbid sleep disorders as well as by voluntary sleep curtailment related to lifestyle and environmental factors, has been implicated in a host of negative consequences. These range from metabolic dysfunction and increased cardiovascular morbidity to impairments in mood and academic performance. The following review will focus on what is currently known about the effects of sleep disordered breathing (SDB) specifically on neurobehavioral and neurocognitive function in children. Because of the scarcity of literature on the cognitive and behavioral impact of sleep disorders in infants and very young children, this review will target largely the preschool/school-aged child and adolescent populations. In addition, the focus will be on a review of the most recent literature, as a supplement to several excellent previous reviews on the topic.

Strategic plan for pediatric respiratory diseases research: an NHLBI working group report

The Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI) recently held a workshop to identify gaps in our understanding and treatment of childhood lung diseases and to define strategies to enhance translational research in this field. Leading experts with diverse experience in both laboratory and patient-oriented research reviewed selected areas of pediatric lung diseases, including perinatal programming and epigenetic influences; mechanisms of lung injury, repair, and regeneration; pulmonary vascular disease; sleep and control of breathing; and the application of novel translational methods to enhance personalized medicine. This report summarizes the proceedings of this workshop and provides recommendations for emphasis on targeted areas for future investigation. The priority areas identified for research in pediatric pulmonary diseases included: (1) epigenetic and environmental influences on lung development that program pediatric lung diseases; (2) injury, regeneration, and repair in the developing lung; (3) pulmonary vascular disease in children; (4) development and adaptation of ventilatory responses to postnatal life; (5) nonatopic wheezing: aberrant large airway development or injury?; (6) strategies to improve assessment, diagnosis, and treatment of pediatric respiratory diseases; and (7) predictive and personalized medicine for children.

Obesity and excessive daytime sleepiness in prepubertal children with obstructive sleep apnea

INTRODUCTION

The epidemic of childhood obesity has prompted remarkable changes in the relative proportions of symptomatic overweight or obese children being referred for evaluation of habitual snoring. However, it remains unclear whether obesity modifies the relative frequency of daytime symptoms such as excessive daytime sleepiness.

METHODS

Fifty consecutive, nonobese, habitually snoring, otherwise-healthy children (age range: 6-9 years) and 50 age-, gender-, and ethnicity-matched obese children (BMI z score: >1.67) underwent an overnight polysomnographic evaluation, followed by a multiple sleep latency test the following day.

RESULTS

The mean obstructive apnea/hypopnea index values for the 2 groups were similar (nonobese: 12.0 +/- 1.7 episodes per hour of total sleep time; obese: 10.9 +/- 1.5 episodes per hour of total sleep time). However, the mean sleep latency for obese children was significantly shorter (12.9 +/- 0.9 minutes) than that for nonobese children (17.9 +/- 0.7 minutes). Furthermore, 21 obese children had mean sleep latencies of < or =12.0 minutes, compared with only 5 nonobese children. Although significant associations emerged between mean sleep latency, obstructive apnea/hypopnea index, proportion of total sleep time with oxygen saturation of <95%, and respiratory arousal index for the whole cohort, the slopes and intersects of the linear correlation of mean sleep latency with any of these polygraphic measures were consistently greater in the obese cohort.

CONCLUSIONS

The likelihood of excessive daytime sleepiness for obese children is greater than that for nonobese children at any given level of obstructive sleep apnea severity and is strikingly reminiscent of excessive daytime sleepiness patterns in adults with obstructive sleep apnea.

Sleep-wake schedules in preschool children who snore

PURPOSE

The aim of the study was to compare sleep-wake schedules between snoring and nonsnoring preschool age children.

MATERIAL AND METHODS

Daytime and nighttime sleep duration, daytime and nighttime symptoms were assessed in 34 children at preschool age who snore (5.38+/-1.21 years) and in 66 age- and sex-matched nonsnorers (5.67+/-1.12 years). The snoring group consisted of children with obstructive sleep apnea (OSA) scores <+3.5 and >-1, the nonsnoring group with OSA score <-1.

RESULTS

Children who snore differ from the nonsnorers in daytime sleep duration (51.62+/-28.9 minutes vs. 10.70+/-20.2 minutes; p<0.001), but not in nighttime sleep (10.97+/-0.52 hours vs. 9.83+/-1.34 hours; p>0.05). The percentage of children with daytime napping was higher in the snoring group than in the nonsnorers (47.1% vs. 9.1%; p<0.00004), and parents-reported behavioral problems were more frequent in children who snore (41.2% vs. 19.7%; p<0.02). Multivariate odds ratios, including variables for nighttime (sleep apnea) and daytime symptoms (daytime napping and oral breathing), showed that regular sleep during the day was the most predictive of snoring (OR=6.1; 95%CI 1.76-21.04; p<0.005).

CONCLUSION

In preschool age children, when the daytime nap begins to disappear, snoring may have an effect on daytime schedule through an increased need for daytime sleep.

Strategic plan for pediatric respiratory diseases research: an NHLBI working group report

The Division of Lung Diseases of the National Heart, Lung and Blood Institute (NHLBI) recently held a workshop to identify gaps in our understanding and treatment of childhood lung diseases and to define strategies to enhance translational research in this field. Leading experts with diverse experience in both laboratory and patient-oriented research reviewed selected areas of pediatric lung diseases, including perinatal programming and epigenetic influences; mechanisms of lung injury, repair, and regeneration; pulmonary vascular disease (PVD); sleep and control of breathing; and the application of novel translational methods to enhance personalized medicine. This report summarizes the proceedings of this workshop and provides recommendations for emphasis on targeted areas for future investigation. The priority areas identified for research in pediatric pulmonary diseases included: (1) epigenetic and environmental influences on lung development that program pediatric lung diseases, (2) injury, regeneration, and repair in the developing lung, (3) PVD in children, (4) development and adaptation of ventilatory responses to postnatal life, (5) nonatopic wheezing: aberrant large airway development or injury? (6) strategies to improve assessment, diagnosis, and treatment of pediatric respiratory diseases, and (7) predictive and personalized medicine for children.

Pediatric sleep apnea: early onset of the 'syndrome'?

Obstructive sleep apnea is a common disorder in childhood, particularly in the last decade when an increased prevalence of obesity has been documented. The neurocognitive and behavioral problems associated with this disorder have been known for a long time. However, the increased knowledge of cardiovascular and metabolic complications in adults with sleep apnea has been followed by a better understanding of the systemic effects of upper airway obstruction in children. Obstructive sleep apnea (OSA) has been shown to induce autonomic imbalance in children and to affect blood pressure, cerebral blood flow and cardiac function in an early phase. OSA may also induce chronic systemic inflammation and may contribute to the development of metabolic syndrome in obese children. Very recent research indicates that in children primary snoring, the mildest form of the sleep-disordered breathing spectrum, may also be associated with morbidity. It is, therefore, likely that these respiratory sleep disorders do not simply influence children's' performance in private and social life, but may more seriously affect children's' health. The aim of this review is to outline early systemic complications of obstructive sleep apnea and primary snoring in infants and children.

Tonsillectomy in children

INTRODUCTION

Tonsillectomy is one of the most frequently performed surgical interventions in children. In the following, indications, preoperative evaluation, surgical techniques and postoperative complications will be discussed.

METHODS

Literature search in PubMed (National Library of Medicine) focusing on publications in German or English up to June 2008.

RESULTS

Indications are selected infectious diseases, upper airway obstruction for example due to tonsillar hypertrophy, and a suspected malignancy. Viral infections of the tonsils without upper airway obstruction are not an indication for surgery; in the case of acute bacterial tonsillitis, tonsillectomy is no longer recommended. In recurrent tonsillitis, tonsillectomy is only effective in specific and narrow indications. The indication for tonsillectomy in sleep-disordered breathing due to adenotonsillar hypertrophy has to be based on clinical assessment, medical history, and a sleep history. The most relevant risk factors are obstructive sleep apnea and coagulation disorders. A standardized history regarding hemostasis and bleeding is mandatory, and is superior to routine coagulation tests. Postoperative bleeding is still the most relevant complication of tonsillectomy and is always an emergency situation.

CONCLUSION

Tonsillectomy is one of the most frequently performed interventions in children but should be considered with care, as life-threatening complications can occur.

The multiple challenges of obstructive sleep apnea in children: morbidity and treatment

PURPOSE OF REVIEW

To delineate some of the major morbid phenotypes that have emerged in pediatric obstructive sleep apnea (OSA), address new concepts in our understanding of OSA-associated morbidities, and elaborate on innovative therapeutic schemes that may improve outcomes for this condition. In addition, the conceptual framework whereby a childhood condition such as OSA can be linked to specific adult diseases will be presented.

RECENT FINDINGS

OSA in children is a frequent condition that affects up to 3% of nonobese, otherwise healthy children. In recent years, increased awareness of OSA and changes in obesity rates in children have contributed to significant changes in disease prevalence and clinical presentation, such that distinct morbidity-related phenotypes have become apparent. Furthermore, oxidative stress and systemic inflammatory pathways are mechanistically involved in the pathophysiology of OSA-associated morbidity. Adenotonsillectomy, the treatment of choice for pediatric OSA, may not be as efficacious as previously thought. Alternative nonsurgical therapies have started to emerge and may become an essential component of treatment.

SUMMARY

Pediatric OSA, particularly when obesity is concurrently present, is associated with substantial end-organ morbidities that primarily but not exclusively affect central nervous and cardiovascular systems. These morbidities are pathophysiologically mediated by inflammatory and free radical mediators. Although adenotonsillectomy remains the first line of treatment, more critical assessment of its role is needed, and incorporation of nonsurgical approaches to pediatric OSA seems warranted.

Metabolic effects of the obstructive sleep apnea syndrome and cardiovascular risk

The obstructive sleep apnea syndrome (OSAS) is characterized by collapse of the upper airway during sleep, recurring apneas, intermittent hypoxemia and daytime somnolence. OSAS is often associated with obesity, and its prevalence is expected to rise due to the obesity epidemics worldwide. OSAS is associated with increased cardiovascular risk which appears to be normalized by treatment with nasal continuous positive airway pressure (nCPAP) during sleep, suggesting an independent role of OSAS in accelerating atherosclerosis. Insulin resistance (IR) and the metabolic syndrome (MetS) are often found in OSAS patients, but the relative role played by OSAS and obesity is still unclear. Both OSAS and MetS may exert negative synergistic effects on the cardiovascular system through multiple mechanisms (hypoxemia, sleep disruption, activation of the sympathetic nervous system, inflammatory activation). Besides nCPAP treatment, pharmacologic interventions to treat obesity and the MetS could improve cardiovascular prevention in OSAS.

Obstructive sleep disordered breathing in children: beyond adenotonsillectomy

Traditionally, adenotonsillectomy (AT) has long been the treatment of choice for obstructive sleep disordered breathing (SDB) in children. AT is usually considered a safe procedure, which cures 80% of children with SDB. Accumulated data have however challenged this overly simplistic view. Indeed, AT is invariably associated with significant morbidity, post-operative pain, and a mortality rate which, though low, cannot be ignored. In addition, aside from a recurrence of SDB at adolescence in an unknown percentage of cases, some recent results suggest that complete SDB cure is not achieved in as much as 75% of cases after AT. Interestingly, several treatment options have been recently proposed for replacing or complementing AT. Continuous positive airway pressure (CPAP) is now suggested in children with remaining SDB after AT; however, compliance and suitability of equipment remain important hurdles, especially in small children and infants. Anti-inflammatory treatments, including nasal glucocorticoids and/or the anti-leukotriene montelukast, appear to hold great promise. Finally, orthodontic treatments are an appealing option, with recent results in children suggesting that it is possible to improve or perhaps even cure SDB in a durable manner by enlarging the nasal passages and/or the oropharyngeal airspace. In conclusion, while we are currently in the midst of an exciting time with several new treatments being developed for childhood SDB, randomized controlled trials are urgently needed to delineate their indications. In the meantime, it appears that systematic detection of orthodontic anomalies and better collaboration with maxillofacial specialists, including orthodontists and/or dentists, is needed for deciding the best treatment options for childhood SDB.

Obesity and persisting sleep apnea after adenotonsillectomy in Greek children

BACKGROUND

The relative importance of obesity and adenotonsillar hypertrophy in the pathogenesis of obstructive sleep-disordered breathing (SDB) in childhood is unclear. Adenotonsillectomy (AT) for SDB is not always curative, and obese children are at increased risk for residual disease postoperatively.

OBJECTIVE

The aim of this investigation was to assess the efficacy of AT as treatment for SDB in obese and nonobese children.

METHODS

Children with adenoidal and/or tonsillar hypertrophy who underwent AT for the treatment of SDB underwent polysomnography preoperatively and postoperatively. A body mass index (BMI) z score of > 1.645 was used to define obesity. The achievement of a postoperative obstructive apnea-hypopnea index (OAHI) of less than one episode per hour (ie, the cure of SDB) was the primary outcome measure.

RESULTS

Twenty-two obese children (mean [+/- SD] age, 5.8 +/- 1.8 years; mean BMI z score, 2.6 +/- 0.8; mean OAHI, 9.5 +/- 9.7 episodes per hour) and 48 nonobese children (mean age, 6.9 +/- 2.6 years; mean BMI z score, 0.09 +/- 1.1; OAHI, 6 +/- 5.4 episodes per hour) were recruited. After surgery, obese and nonobese subjects did not differ in the efficacy of AT (postoperative OAHI of less than one episode per hour, 22.7% vs 25% of subjects, respectively; p > 0.05). The presence of obesity, adenoidal or tonsillar hypertrophy, gender, and postoperative BMI change were not significant predictors of SDB cure.

CONCLUSIONS

Obesity does not necessarily predict an unfavorable outcome of AT as treatment for SDB.

Obstructive sleep apnea in children: implications for the developing central nervous system

Recent increases in our awareness to the high prevalence of sleep disorders in general and of sleep-disordered breathing among children, in particular, has led to concentrated efforts aiming to understand the pathophysiological mechanisms, clinical manifestations, and potential consequences of such conditions. In this review, I will briefly elaborate on some of the pathogenetic elements leading to the occurrence of obstructive sleep apnea (OSA) in children, focus on the psychobehavioral consequences of pediatric OSA, and review the evidence on the potential mechanisms underlying the close association between central nervous system morbidity and the episodic hypoxia and sleep fragmentation that characterize OSA.