Update on pathophysiology and treatment of childhood obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is common in childhood and is characterized by recurrent upper airway obstructive events during sleep that produce significant neurocognitive and cardiovascular sequelae. The pathophysiology of childhood OSAS is complex and involves mechanical airway obstruction often secondary to adenotonsillar hypertrophy. However, neuromotor abnormalities and instability of central ventilatory control are also implicated. Several surgical and non-surgical treatment options for childhood OSAS are available, and will be discussed. Some of these include adenotonsillectomy, lingual tonsillectomy, supraglottoplasty, continuous positive airway pressure (CPAP), rapid maxillary expansion, oral appliance therapy, anti-inflammatory treatments, and supplemental oxygen.     

Obstructive sleep apnea syndrome in infants and children]

Obstructive sleep apnea syndrome (OSAS) is characterized by prolonged, generally partial, upper airway obstruction associated with hypoxemia and/or hypercapnia. Main etiological factors include hypertrophy of the tonsils and adenoids, craniofacial abnormalities with reduction in the upper airway caliber, abnormality of neural upper airway control, or a combination of these factors. Symptoms depend on age, but they always include snoring and breathing difficulties during sleep. Diagnosis of OSAS must be established early in order to prevent complications. It is suspected on history, physical examination and investigative confrontation such as nasofibroscopy and imaging. Polysomnography is the gold standard for diagnosis, scoring of the obstruction and distinction between primary snoring and obstructive breathing. Adenotonsillectomy is an effective therapy. For selected patients, craniofacial surgery may be helpful. Some children require continuous positive airway pressure or the nasopharyngeal tube. Tracheotomy is rarely indicated.     

Magnetic resonance imaging of obstructive sleep apnea in children

Sleep-disordered breathing has a spectrum of severity that spans from snoring and partial airway collapse with increased upper airway resistance, to complete upper airway obstruction with obstructive sleep apnea during sleeping. While snoring occurs in up to 20% of children, obstructive sleep apnea affects approximately 1–5% of children. The obstruction that occurs in obstructive sleep apnea is the result of the airway collapsing during sleep, which causes arousal and impairs restful sleep. Adenotonsillectomy is the first-line treatment of obstructive sleep apnea and is usually effective in otherwise healthy nonsyndromic children. However, there are subgroups in which this surgery is less effective. These subgroups include children with obesity, severe obstructive sleep apnea preoperatively, Down syndrome, craniofacial anomalies and polycystic ovarian disease. Continuous positive airway pressure (CPAP) is the first-line therapy for persistent obstructive sleep apnea despite previous adenotonsillectomy, but it is often poorly tolerated by children. When CPAP is not tolerated or preferred by the family, surgical options beyond adenotonsillectomy are discussed with the parent and child. Dynamic MRI of the airway provides a means to identify and localize the site or sites of obstruction for these children. In this review the authors address clinical indications for imaging, ideal team members to involve in an effective multidisciplinary program, basic anesthesia requirements, MRI protocol techniques and interpretation of the findings on MRI that help guide surgery.     

儿童睡眠呼吸暂停的诊断及治疗进展

睡眠呼吸暂停包括阻塞性、中枢性及混合性睡眠呼吸暂停。目前有5.7％的儿童患有阻塞性睡眠呼吸暂停综合征,其危害包括影响生长、发育、认知及行为等方面,同时会增加心脏血管疾病的风险。因此关注阻塞性睡眠呼吸暂停综合征儿童早期的诊断及治疗更有意义。阻塞性睡眠呼吸暂停首选的治疗是扁桃体切除术,其他治疗包括连续的正压通气、抗炎治疗、气道调节器及咽腔矫正器等。中枢性睡眠呼吸紊乱与呼吸中枢不成熟及发育异常有关。中枢性呼吸暂停可能是遗传性的,或者是后天获得性的,因此中枢性呼吸暂停的治疗主要是病因学治疗。     

Radiologic evaluation of adenoids and tonsils in children with obstructive sleep apnea: Plain films and fluoroscopy

Twenty-six children with obstructive sleep apnea were evaluated by lateral neck radiographs during wakefulness, and by polygraphic monitoring and upper airway fluoroscopy during natural sleep. Children with craniofacial abnormalities, palatal surgery, and central nervous system disease were excluded from the study. Moderate or marked enlargement of tonsils and adenoids was noted on lateral neck radiographs of 18 of 26 patients. An objective measure of adenoidal enlargement, the adenoidal-nasopharyngeal ratio, correlated well with subjective judgment of adenoidal size but was not generally more useful than subjective estimation. Upper airway fluoroscopy demonstrated the site and mechanism of obstruction in all patients. Because all children with moderate to marked adenotonsillar enlargement demonstrated obstruction at the adenoidal or tonsillar level on fluoroscopy, we now screen children with suspected sleep apnea with lateral airway radiographs and polysomnography. Fluoroscopy is reserved for children with mild adenotonsillar enlargement, craniofacial dysplasia, prior cleft palate repair, or neuromuscular disorders. These results suggest that the pathogenesis of obstructive sleep apnea in children involves anatomic factors which narrow the upper airway, sleep-related hypotonia of pharyngeal dilator musculature, and compensatory mechanisms to prevent or alleviate asphyxia.     

Obstructive sleep apnea syndrome in childhood

Obstructive sleep apnea syndrome (OSAS) is a well-known clinical entity in adults but until now it has been less well studied in children. Several studies have shown that the prevalence of pediatric OSAS is high (between 1% and 3%) and its consequences can be serious. Major risk factors for OSAS in children include adeno-tonsillar hypertrophy, neuromuscular disease and syndromes such as Down's or Pierre-Robin's syndrome. Definitive diagnosis is by nocturnal polysomnography while other methods such as cardiorespiratory records and nocturnal pulse oximetry are undoubtedly useful. Adenotonsillectomy plays a major role in the treatment of OSAS. Nasal continuous positive airway pressure is an alternative in children who show poor response to surgical treatment or in those with craniofacial alterations. In a few cases, nocturnal oxygen administration can be useful.     

The snoring child

Snoring is a common manifestation of obstructive sleep apnea and represents one end of the spectrum of sleep-related breathing disorders. Children with primary snoring initially may develop OSAS later, so inquiring about symptoms of OSAS should be part of each visit. Obstructive sleep apnea can result in serious cardiovascular and metabolic consequences and neurocognitive deficits. Adenotonsillar hypertrophy remains the most common cause of OSA although the rising prevalence of obesity is of increasing importance. Polysomnography remains the gold standard in the diagnoses of OSAS and in assessing the risks associated with surgery. Most children with OSAS can be treated with adenotonsillectomy in the ambulatory surgery center. However, there are children at risk for severe OSAS and for postoperative complications, who will need PICU care. In addition to adenotonsillectomy, OSAS can be treated successfully in referral centers with other surgical approaches and by the use of positive airway pressure. Children with obesity-related OSAS often require CPAP or BPAP for control of OSAS.     

Diagnosis and therapy of obstructive sleep apnea syndrome in children with premature craniosynostosis syndromes

Sleep related breathing disorders are a common symptom in children with craniosynostosis syndromes, as upper airways may be narrowed by midfacial hypoplasia.To better characterize the sleep related apneas, 24 children with syndromal craniofacial dysplasia underwent 68 poly-somnographies. 9 patients had reexaminations after therapeutic procedures. 4 patients had severe obstructive sleep apnea syndrom (OSAS), 8 patients had moderate and 11 patients mild obstructive sleep apnea respectivly. Only one child had no obstructive sleep apnea. Children with Morbus Crouzon tended to have moderate to severe breathing disorders (9/14) whereas Apert patients mostly had no or light breathing disorders (6/7). Number of central apneas was increased as well. Sleep architecture was not significantly impaired. Apneas were more frequent during REM-sleep. Nasal CPAP, BiPAP and adenotonsillectomy improved respiratory parameters.Pulse oxymetry can be used as a screening method because of the good correla-tion of oxygen desaturation index with severity of OSAS. Frequent examinations and, if necessary, adaptation of therapy is indicated as OSAS in -these children may be rapidly changing. We suggest a guideline for diagnostics and therapy.     

Obstructive sleep apnea in children: an update

The diagnosis of obstructive sleep apnea in children requires clinical suspicion supplemented with the use of specific diagnostic tests. Polysomnography remains the key to diagnosis, and helps to assess the need for treatment, the risk for perioperative respiratory compromise, and the likelihood of persistent OSAS after treatment. Adenotonsillectomy is the mainstay of treatment, although children with complex medical conditions that affect upper airway anatomy and tone may require additional treatment.     

Obstructive sleep apnea syndrome in children

Partial or complete repetitive obstructions of the upper airway during sleep give rise to clinical symptoms associated with heavy, chronic snoring. The number of obstructive sleep apneas during the night may be less important than the repetitive inspiratory increases in upper airway resistance, even if these are associated only with a partial airway collapse. Oxygen saturation may not be severely affected by partial occlusion during nocturnal recording, although clinical symptoms may occur. Esophageal pressure measurements and breathing frequency during sleep are key features in the polygraphic evaluation of prepubertal children. Tonsillectomy and adenoidectomy may be helpful in treating children with small upper airway during sleep. The marked interaction between upper airway adequacy and craniofacial morphology make it critical to evaluate the impact of partial or complete airway occlusion during sleep on facial prognathism. Nasal continuous positive airway pressure is a safe treatment for persistent, partial or complete upper airway occlusion during sleep, but it does not address the mandibular deficiency often seen in symptomatic children. Orthodontic evaluation and treatment may make maxillomandibular surgery unnecessary during the pubertal years.     

Hypoxic arousal responses in infants with bronchopulmonary dysplasia

Infants with bronchopulmonary dysplasia have a high incidence of sudden, unexplained death in the postneonatal period, yet the cause of these deaths is unknown. Frequent episodes of clinically unsuspected arterial oxygen desaturation have recently been described in infants with bronchopulmonary dysplasia. We hypothesized that infants with bronchopulmonary dysplasia who experience frequent episodes of hypoxia may have abnormal arousal responses to these hypoxic episodes. We studied 12 infants with bronchopulmonary dysplasia at 41.4 +/- 1.3 weeks postconceptional age. Hypoxic arousal responses were performed during quiet sleep at an inspired oxygen tension of 80 mm Hg for a maximum of three minutes or until arousal occurred. Of 12 infants, 11 (92%) aroused normally to the hypoxic challenge. However, all infants required vigorous stimulation and supplemental oxygen after the initial arousal response. Of 12 infants with bronchopulmonary dysplasia, eight (67%) experienced prolonged apnea with bradycardia, and four of 12 (33%) required brief ventilatory assistance (bag and mask) to restore normal breathing. Abnormal pneumographic findings did not predict the occurrence of these prolonged periods of apnea and bradycardia following hypoxia. We conclude that an abnormal response to hypoxia following arousal may lead to prolonged apnea and bradycardia in infants with bronchopulmonary dysplasia. We speculate that the inability to recover from this hypoxia may result in sudden death in these infants.     

Obstructed breathing in children during sleep monitored by echocardiography

Six 3 to 14-year-old boys with snoring and obstructive sleep apnea syndrome were monitored polygraphically during sleep with and without nasal continuous positive airway pressure with simultaneous recording of esophageal pressure (P_es) and M-mode and two-dimensional echocardio-grams. Continuous non-invasive blood pressure monitoring was performed in two older children. Three of the six children demonstrated a diastolic leftward shift of the interventricular septum related to the negativity of P_es. Progressively more negative P_es correlated significantly with an increase in right ventricular internal end-diastolic dimension and a decrease in left ventricular internal end-diastolic dimension, with at times left ventricular "collapse". One of the subjects with blood pressure monitoring demonstrated pulsus paradoxus with leftward shift of the interventricular septum. Nasal continuous positive airway pressure normalized all changes. Pulsus paradoxus and leftward shift of the interventricular septum are related to the mechanical changes associated with heavy snoring during sleep, regardless of the amount of oxygen desaturation.     

Obstructed breathing in children during sleep monitored by echocardiography

Six 3 to 14-year-old boys with snoring and obstructive sleep apnea syndrome were monitored polygraphically during sleep with and without nasal continuous positive airway pressure with simultaneous recording of esophageal pressure (P_es) and M-mode and two-dimensional echocardio-grams. Continuous non-invasive blood pressure monitoring was performed in two older children. Three of the six children demonstrated a diastolic leftward shift of the interventricular septum related to the negativity of P_es. Progressively more negative P_es correlated significantly with an increase in right ventricular internal end-diastolic dimension and a decrease in left ventricular internal end-diastolic dimension, with at times left ventricular "collapse". One of the subjects with blood pressure monitoring demonstrated pulsus paradoxus with leftward shift of the interventricular septum. Nasal continuous positive airway pressure normalized all changes. Pulsus paradoxus and leftward shift of the interventricular septum are related to the mechanical changes associated with heavy snoring during sleep, regardless of the amount of oxygen desaturation.     

Sleep and breathing abnormalities in a case of Prader-Willi syndrome. The effects of acute continuous positive airway pressure treatment

This report describes the polysomnographic findings and the respiratory alterations during sleep in a 20-year-old patient with the Prader-Willi syndrome. Nocturnal recordings and a variant of the multiple sleep latency test showed excessive daytime sleepiness, sleep onset rapid eye movement episodes, snoring and sleep apnea. Treatment with nasal continuous positive airway pressure normalized the respiratory pattern and the sleep structure, except for rapid eye movement sleep onset. Whereas upper airway obstruction and obesity may explain the respiratory disorders, as shown by their resolution with continuous positive airway pressure treatment, hypothalamic dysfunction could play a role in the disruption of the normal nonrapid eye movement/rapid eye movement sleep periodicity.     

Obstructive sleep apnea in children with Down syndrome.

Children with Down syndrome have many predisposing factors for the obstructive sleep apnea syndrome (OSAS), yet the type and severity of OSAS in this population has not been characterized. Fifty-three subjects with Down syndrome (mean age 7.4 +/- 1.2 [SE] years; range 2 weeks to 51 years) were studied. Chest wall movement, heart rate, electroculogram, end-tidal PO2 and PCO2, transcutaneous PO2 and PCO2, and arterial oxygen saturation were measured during a daytime nap polysomnogram. Sixteen of these children also underwent overnight polysomnography. Nap polysomnograms were abnormal in 77% of children; 45% had obstructive sleep apnea (OSA), 4% had central apnea, and 6% had mixed apneas; 66% had hypoventilation (end-tidal PCO2 greater than 45 mm Hg) and 32% desaturation (arterial oxygen saturation less than 90%). Overnight studies were abnormal in 100% of children, with OSA in 63%, hypoventilation in 81%, and desaturation in 56%. Nap studies significantly underestimated the presence of abnormalities when compared to overnight polysomnograms. Seventeen (32%) of the children were referred for testing because OSAS was clinically suspected, but there was no clinical suspicion of OSAS in 36 (68%) children. Neither age, obesity, nor the presence of congenital heart disease affected the incidence of OSA, desaturation, or hypoventilation. Polysomnograms improved in all 8 children who underwent tonsillectomy and adenoidectomy, but they normalized in only 3. It is concluded that children with Down syndrome frequently in have OSAS, with OSA, hypoxemia, and hypoventilation. Obstructive sleep apnea syndrome is seen frequently in those children in whom it is not clinically suspected. It is speculated that OSAS may contribute to the unexplained pulmonary hypertension seen in children with Down syndrome.     

手术治疗腺样体肥大儿童阻塞性睡眠呼吸暂停综合征

目的　探讨腺样体切除术、腺样体扁桃体切除术对腺样体肥大儿童阻塞性睡眠呼吸暂停综合征(OSAS)的治疗作用。方法　对 2 0例腺样体肥大合并OSAS(OSAS组 )儿童手术前后的临床表现、多导睡眠图(PSG)检查结果进行前瞻性比较研究 ,并与同期住院的 1 0例单纯性腺样体肥大儿童 (对照组 )进行对照研究。结果　OSAS组的常见症状发生率与对照组差异无显著性 (P >0 .0 5 ) ;两组体块指数分别为 1 5 .4± 2 .5kg/m2 和1 7.6± 3.1kg/m2 ,差异无显著性 (P >0 .0 5 )。OSAS组与对照组的鼻咽侧位片A/n值、总睡眠时间、睡眠效率及S1、S2、慢波睡眠 (SWS)、快速眼动睡眠期 (REM)所占比例差异均无显著性 (P >0 .0 5 )。OSAS患儿术后呼吸暂停指数 (AI)、呼吸暂停低通气指数 (AHI)、阻塞性呼吸暂停指数 (OAI)较术前降低 (P <0 .0 5或 0 .0 1 ) ,REM所占比例较术前增高 (P <0 .0 5 )。结论　腺样体肥大合并OSAS的临床表现、鼻咽侧位片A/n值、睡眠结构与单纯腺样体肥大患儿无差别 ;腺样体肥大合并OSAS儿童手术治疗效果良好。     

Sleep and Breathing Abnormalities in a Case of Prader-Willi Syndrome: The Effects of Acute Continuous Positive Airway Pressure Treatment

ABSTRACT. This report describes the polysomnographic findings and the respiratory alterations during sleep in a 20-year-old patient with the Prader-Willi syndrome. Nocturnal recordings and a variant of the multiple sleep latency test showed excessive daytime sleepiness, sleep onset rapid eye movement episodes, snoring and sleep apnea. Treatment with nasal continuous positive airway pressure normalized the respiratory pattern and the sleep structure, except for rapid eye movement sleep onset. Whereas upper airway obstruction and obesity may explain the respiratory disorders, as shown by their resolution with continuous positive airway pressure treatment, hypothalamic dysfunction could play a role in the disruption of the normal nonrapid eye movement/rapid eye movement sleep periodicity.     

An update on childhood snoring

Habitual snoring or daily snoring is a symptom of sleep-disordered breathing (SDB) in children and it is reported in about 10% of children. SDB includes primary snoring, upper airway resistance syndrome (UARS), obstructive hypoventilation syndrome and obstructive sleep apnea syndrome (OSAS). Classification of SDB in a particular snoring child requires an overnight polysomnography (PSG). Manual scoring of PSG is mandatory in children. Risk factors for SDB include allergic rhinitis, passive smoking, obesity, dysmorphic syndromes and neuromuscular disorders. Conclusion: Treatment includes general measures like treatment of allergic rhinitis, weight reduction in obese children, and avoidance of sleep deprivation. Specific measures include removal of adenoid and tonsils. Complications of SDB include neurocognitive impairment, hypertension and failure to thrive.     

Elevated catecholamine levels and abnormal hypoxic arousal in apnea of infancy

Arousal from quiet sleep in response to a hypoxic challenge fails to occur in many patients with apnea of infancy. It was hypothesized that catecholamine-mediated responses might be involved in the depressed hypoxic arousal response in apnea of infancy and that these differences would be reflected in serum catecholamine concentrations. Fifteen infants with a median age of 5.5 months and a history of unexplained apnea during sleep were studied. Two hypoxic challenges (PiO2 80 mm Hg) were given for three minutes or until arousal from quiet sleep occurred. Of the 15 patients with apnea of infancy 11 (73%) did not arouse to hypoxia. These infants had serum epinephrine levels that were elevated 4.1-fold while awake (P less than .05), 3.4-fold during quiet sleep (P less than .02), and 3.5-fold during hypoxia (P less than .05). They also had serum norepinephrine levels that were elevated threefold while awake (P less than .05), 5.3-fold during quiet sleep (P less than .001), 3.2-fold during hypoxia (P less than .02), and 12-fold during recovery from hypoxia (P less than .001) in comparison with the corresponding levels in the four (23%) infants who aroused normally to hypoxia. It is speculated that elevated circulating catecholamines are associated with abnormal hypoxic arousal responses in children with apnea of infancy.     

Decreased specific airway conductance in infant apnea

A disorder of respiratory control is the suspected etiology in a majority of infants with apnea. Although neurologic control of breathing has been evaluated in infants surviving an apneic episode, pulmonary mechanics have not been previously measured. Pulmonary mechanics were measured during sleep in ten infants with apnea, aged 45.4 +/- 1.4 (SE) weeks postconception, and 13 control infants, aged 42.0 +/- 0.8 weeks postconception. Infant apnea patients were defined as those having at least one episode of cyanosis, limpness, and apnea requiring vigorous stimulation or resuscitation to restore normal breathing, and in whom no treatable etiology could be found. Thoracic gas volume, airway resistance, and specific airway conductance were measured in an infant body pressure plethysmograph during quiet breathing. Dynamic pulmonary compliance was measured in six infants using an esophageal balloon. Specific airway conductance was decreased in infants with apnea compared with control infants (P less than .05). Thoracic gas volume, airway resistance, and dynamic pulmonary compliance values were comparable with those of control infants. These data suggest that airway narrowing or abnormal control of airway tone during sleep may contribute to apnea in some infants.