Issues related to the diagnosis and treatment of sleep apnea in children
Li Yanzhong
(Department of Otolaryngology, Head and Neck Surgery, Qilu Hospital, Shandong University; Key Laboratory of Otolaryngology, Ministry of Health
Jinan 250012)
Children have great differences from adults in growth, development, metabolism, respiratory physiology, sleep-wake rhythm, etc. Some of them have signs of sleep-disordered breathing (SDB), but they also have certain specificities in etiology, clinical manifestations, diagnostic criteria and treatment effects. Li Yanzhong, Department of Otolaryngology, Qilu Hospital, Shandong University
Sleep-related respiratory disorders in children are divided into three types: simple snoring, obstructive sleep apnea hypopneasyndrome (OSAHS) and upper airway resistance syndrome, and the clinical symptoms and signs of the children do not always accurately reflect the severity of the disease. The majority of children with OSAHS have simple snoring, which is not characterized by changes in sleep structure, alveolar hypoventilation and hypoxia, but some children with OSAHS have loud snoring, typical apnea or partial upper airway obstruction with reduced oxygen saturation; however, some children do not have obvious snoring symptoms, and parents may observe obvious wheezing after intervals of breathing. In children with upper airway resistance syndrome, the increase in upper airway resistance during sleep mostly occurs during rapid eye movement (REM) sleep, resulting in negative intrathoracic pressure fluctuations during inspiration, increased respiratory motion, transient awakening and sleep fragmentation, but normal nasal and oral airflow and oxygen saturation, and no apnea and hypoventilation. Intraesophageal manometry and polysomnography can help to confirm the diagnosis. These three sleep-related breathing disorders may co-exist or alternate in the same child at different times due to upper respiratory tract infections or changes in sleep position. Although OSAHS has similar pathophysiological changes in children and adults, clinicians must be aware of the significant differences in diagnosis and treatment in order to avoid underestimating the condition in pediatric patients.
1 Epidemiology
SDB in children is a group of sleep disorders with a high prevalence. Epidemiological surveys show that the prevalence of OSAHS in children is between 1 % and 3 %, and the prevalence may be higher when snoring is aggravated by upper respiratory tract infection. And the prevalence of snoring in children is as high as 8 % to 12 % [1]. We have investigated the incidence of SDB and related problems in preschool children aged 3-6 years and school-age children aged 7-13 years in Jinan city, and in preschool children who snore frequently (2-3 times/week) accounted for 6.5%; snoring every night accounted for 3.6%, and those with apnea were 2.4%. Those who snored 2 to 3 times/week during sleep in school-age children accounted for 17.7%; those who snored every night accounted for 4%. There were 31 cases with apnea, accounting for 1.9%. The risk factors associated with snoring included poor nasal ventilation, male, father snoring, and mother snoring; the risk factors associated with apnea included snoring, poor nasal ventilation, and recurrent tonsillitis [2]. The findings of some other authors at home and abroad are as follows: the incidence of snoring and apnea among children aged 2 to 14 years in Guangzhou was 4.65% and 0.49%, respectively [3]; the incidence of snoring and apnea among children aged 3 to 14 years in Nanning was 2.79% and 1.30%, respectively, with frequent snoring during sleep among children aged 3 to 5 years at 8.5% sleep apnea at 3.97% [4]; Shanghai The prevalence of frequent snoring in preschool children was 6.14% [5]; the prevalence of snoring and apnea in school-age children in Hong Kong was 10.9% and 1.5%, respectively [6]; the prevalence of habitual snoring and apnea in preschool children in the UK was 7.9% and 0.9%, respectively [7].
2 Etiology
The most frequent etiology of SDB in children is tonsillar and adenoidal hypertrophy, especially of the adenoids. Tonsillar and adenoid hypertrophy leads to increased resistance of the upper airway during inspiration, negative pressure in the pharyngeal cavity, and the soft palate and tongue root close to the posterior pharyngeal wall, especially in the supine position, resulting in poor sleep breathing, and open-mouth breathing in children, which in turn leads to dryness of the oropharynx, weakened local resistance, and susceptibility to upper respiratory tract infection, which in turn leads to lymphoid tissue hyperplasia in the pharynx and further enlargement of the tonsils and adenoids The lymphatic tissues of the pharynx are enlarged and the tonsils and adenoids are enlarged. Repeated respiratory infections cause the tonsils and adenoids to continue to swell, and the symptoms of OSAHS worsen and are not easily relieved. This is often the main reason for OSAHS visits in children. Kaditis AG et al [8] studied the size of tonsils in snoring and non-snoring children aged 2 to 14 years and found that both young and old children with SDB had enlarged tonsils, while in non-snoring older children the size of tonsils was significantly smaller than in young non-snoring children. The enlarged tonsils in children with SDB may have formed at a younger age and not shrink with age. The other possible causes of SDB in children are: pharyngeal wall invagination caused by the reduced tone of pharyngeal dilator muscle groups, upper airway obstruction inducing snoring and apnea, pediatric obesity prone to SDB because of the accumulation of soft tissue fat around the upper airway in obese people, resulting in the relative narrowing of the upper airway, prone to airflow obstruction, and other causes such as nasal obstruction, maxillofacial deformity, macroglossia, mandibular recession, neuromuscular disorders, laryngeal softening, etc. SDB may also occur. The relationship between SDB and allergic rhinitis in children is often encountered in clinical practice, and many children with SDB have symptoms such as nasal congestion, open-mouth breathing, snoring and apnea, as well as allergic rhinitis such as nasal itching, runny nose and sneezing. This is not reported in China. Some foreign scholars found that children with excessive exposure to some allergic factors or allergic diseases after birth have an increased risk of snoring. The risk factors for snoring in children are similar to those for allergic rhinitis, and snoring may be a part of allergic diseases, and this study can help clinicians to effectively control snoring in preschool children[9] .
3 Clinical presentation
The clinical presentation of children with SDB varies according to age, with children <5 years of age having the most pronounced nocturnal symptoms; children ≥5 years of age may also exhibit nonspecific behavioral abnormalities during the day. Children with SDB are often seen in otolaryngology or respiratory medicine for sleep snoring, breath-holding, open-mouth breathing, and tonsillar hypertrophy; in pediatrics for growth retardation, malnutrition, and pulmonary hypertension; in neurology or psychiatry for night terrors, nocturnal crying, enuresis, and hyperactivity; and in endocrinology for rapid obesity within a short period of time. Therefore, it is important for physicians to have an understanding of the physiopathological changes involved in children's sleep.
The most easily observed symptoms in children with SDB sleep are sleep disturbance, labored breathing, open mouth breathing, snoring, abnormal respiratory movements, most children have abnormally loud snoring at the end of persistent obstructive apnea, but some children do not have obvious snoring symptoms; abnormal sleep positions, such as cervical hyperextension, prone, knee-chest position, semi-sitting position, high pillow support sleep, etc., can also be seen to improve The upper airway ventilation during sleep can be improved. Children with frequent nocturnal breathing disorders are rarely accompanied by significant daytime sleepiness, i.e., daytime sleepiness is not common in children with OSAHS, and this is one of the most important differences in clinical presentation between children with OSAHS and adults. The reasons for this may be the following: (1) the rhythmic changes of sleep-wake are age-related, and the proportion of NREM3 and 4 deep sleep and REM sleep is higher in children; prolonged partial upper airway obstruction can be self-aborted, and sleep-wake does not occur at the end stage; (2) daytime napping and snoozing are frequent in children, and it is a normal physiological phenomenon in children under 5 years of age, so daytime sleepiness is difficult to identify in the pediatric population; (3) above children The proportion of obstructive apnea is less than that of adults, and it may not be manifested as obvious awakening during sleep. Although PSG monitoring has shown the presence of microarousals during sleep in children with OSAS and the resulting sleep fragmentation, sleep deprivation due to hypoxia or sleep fragmentation associated with apnea may be the main reason for the increased incidence of abnormal sleep behavior in children. Microarousals have been considered in relation to the proportion of sleep stages, the time spent awake during sleep, and the overall sleep efficiency. Children with severe daytime sleepiness and frequent napping should be considered for the presence of sleep deprivation or episodic sleep disorder based on clinical history.
About 15% of children with OSAS have adenoid facies (long face syndrome), which is characterized by long and narrow jaws, high arched palatal arches, receding mandibles, short lengths, large craniocervical angles, poorly developed midface, and protruding upper incisors with uneven teeth. Because most children’s craniofacial development is 60% complete by the age of 4 and 90% complete by the age of 11, childhood is an important stage in the formation of respiratory pattern, and once established, it is difficult to change; most children with OSAS can change from transoral to transnasal breathing pattern 5 years after adenoidectomy, and their original maxillofacial features have been restored to varying degrees.
Developmental delay is one of the main characteristics of children with OSAS during the growth spurt, including short stature and low weight, which can be reversed after treatment in young children; after adenoidectomy, appetite improves and growth rate increases. Although obesity is not necessarily associated with the development of OSAS in children, morbidly obese children have a relatively high incidence of OSAS, and children aged 5 to 12 years with a history of rapid weight gain are at risk for OSAS, which may be related to sleep breath-holding, nighttime hypoxia, and sleep fragmentation, leading to daytime sleepiness and reduced activity, while hypoxic metabolism leads to increased eating and a vicious cycle.
Patients with OSAS in children may exhibit nonspecific behavioral disorders, such as withdrawn personality, dull expression, abnormal shyness, hyperactivity, irritability, aggressive tendencies or rebellious behavior; loss of appetite, malnutrition, and reluctance to go to bed at night in about 1/4 of children; open-mouth breathing when awake due to adenoid hypertrophy, morning headache, dry mouth, and mental depression; cognitive dysfunction, decreased intellectual behavior and learning ability; and decreased attention span and mood swings. A number of clinical reports have confirmed that these symptoms can be reversed and returned to normal with the cure of OSAS.
The clinical course of OSAS in children is varied, and with the development of the disease, developmental delay, neurological dysfunction, pulmonary hypertension, congestive heart failure, pulmonary heart disease, respiratory failure, and increased intracranial pressure have been reported, while erythrocytosis is rare; most of them can resolve on their own after correction of upper airway obstruction. However, some children with pulmonary heart disease may resolve on their own due to atrophy of the enlarged tonsils and adenoids, which are the most common causes of upper airway obstruction in children.
4 Diagnostic criteria and evaluation
The diagnosis of OSAS in children should rely on the following.
4.1 Basic medical history For suspected children with sleep snoring, enhanced respiratory movements, open-mouth breathing and growth retardation, we should carefully inquire about sleep time, sleep quality, sleep behavior and position, nature and intensity of snoring, breathing and its accompanying sounds, morning waking time, daytime snoozing pattern and behavioral functions; and comprehensively record the growth and development history such as height and weight, according to the criteria of OSAS quality-of-life survey in children, with Body mass index (BMI) ≥30Kg/m2 was considered obese, 25＜BMI＜30Kg/m2 was considered overweight, and BMI≤25Kg/m2 was considered normal. 4.2 Physical examination included ① routine ENT examination to determine the upper airway patency and exclude craniofacial structural deformities. The reduction of the right and left diameters of the oropharyngeal cavity by the palatine tonsils was considered 1° for 0%-25%, 2° for 26%-50%, 3° for 51%-75%, and 4° for 76-100%; ② fiberoptic nasopharyngoscopy to observe the nasal cavity, nasopharynx, posterior cut-off area of the soft palate, tongue root, eccrine airway, laryngeal cavity and other structures, and to record the extent of nasal aperture after adenoidal blockage, with 0%-25% as 1°, 26%-50% as 2°, 51%-75% as 2°. 2°, 51%-75%-3°, 76%-100%-4°, which is very important for the comprehensive assessment of the extent of upper airway obstruction. (iii) Lateral cephalometric radiographs were taken to observe adenoid hypertrophy and obstruction of the nasopharyngeal airway, hyoid hypertrophy, and epiglottis airway. The range of adenoids blocking the nasopharyngeal airway was recorded on lateral cranial radiographs, and the vertical distance from the most prominent point of adenoids to the bone surface of the skull base was used as the thickness of adenoids, and the distance between the posterior end of the hard palate and the intersection of the pterygoid plate and the skull base was used as the width of the nasopharyngeal airway, and the ratio between the two was normal at 0.5-0.6, moderate hypertrophy at 0.61-0.70, and pathological hypertrophy at 0.71 or above. (4) Blood pressure, electrocardiogram, chest X-ray to exclude cardiopulmonary complications.
4.3 Polysomnography (PSG) It is mainly used to clarify the diagnosis, to understand the severity of the disease, to assess the risk of surgery and to observe the efficacy of surgery. The ideal environment for monitoring children is to use specially trained sleep technologists who have studied sleep in children, who can gain the child’s trust and share the parents’ anxiety; the parents should sleep with the child in a different bed in the same room on the night of monitoring. The criteria for determining sleep apnea events can have a significant impact on the determination and severity of the disease. AHI >5 times/hour is generally considered pathological, and according to the latest diagnostic criteria of the Chinese Medical Association for OSAHS in children (Urumqi)[10] , obstructive sleep apnea (OSA) is the cessation of oral and nasal airflow during sleep, but thoracoabdominal breathing is still present. Hypopnea (hypopnea) is defined as a 50% reduction in peak oral and nasal airflow signals with a decrease in oxygen saturation of 0.03 or more and/or arousal. The duration of the respiratory event was defined as greater than or equal to 2 respiratory cycles. Increased upper airway resistance, narrowing or even collapse during sleep can lead to a variety of diseases such as upper airway resistance syndrome (UARS), hypoventilation and apnea, etc. Primary snoring (PS) was once considered a benign disease that did not require treatment. PS and OSAHS are only two manifestations of increased upper airway resistance. One study found a correlation between nocturnal sleep snoring and poor school performance and decreased academic achievement in children with PS, and after a questionnaire survey of parents, it was found that snoring symptoms were more pronounced in children who performed poorly in school than in those who performed well [11].Kennedy et al [12] showed that children with PS were cognitively impaired, although PSG monitoring results were within normal limits, and overall IQ scores were lower than normal controls, and there was a correlation between the degree of reduced blood oxygen, the number of respiratory-related microarousals and the degree of reduced cognitive ability. In addition, O’Brien et al [13] found that untreated children with PS had lower neurocognitive function than children without snoring and were more likely to have symptoms such as inattention, anxiety and depression. Based on the above abnormal sleep breathing manifestations, accurate clinical assessment of various breathing abnormalities that occur during sleep in children should be made, and accurate and objective diagnostic criteria should be developed by combining different laboratories, different populations, continuous case observations and the degree of impact of the disease on health status.
4.4 Assessment of Child Behavior Scales The Conners Child Behavior Scales are designed to assess children’s behavior problems, especially attention deficit hyperactivity disorder, and include parent questionnaires, teacher questionnaires, and brief symptom questionnaires. (5) restlessness; (6) lack of concentration and easily distracted; (7) need to meet demands immediately and easily discouraged; (8) rapid and intense mood changes; (9) frequent crying; and (10) sudden anger or unexpected behavior. Each of the above items is scored according to the degree of activity: 0 is none; 1 is slightly; 2 is more; 3 is a lot. A total score of more than 10 has diagnostic significance. We used the Conners’ Child Behavior Inventory, which is commonly used to assess children’s behavior problems, especially attention deficit hyperactivity disorder, as a standard scale to assess whether children have abnormal behavior, and found that children with SDB, including OSAHS and simple snoring, had a 52.3% and 48.3% incidence of abnormal behavior, respectively. The incidence of behavioral abnormalities is also higher in children with simple snoring, which should attract clinical attention [14].
5 Treatment
The treatment of SDB in children includes surgery, conservative medical treatment, and noninvasive positive pressure ventilation treatment, etc. The treatment plan should rely on clinical examination and laboratory monitoring data, with special emphasis on individualized and targeted treatment plans selected according to the individual and time.
5.1 Tonsil and/or adenoidectomy Enlarged tonsils and adenoids are the most common cause of upper airway restrictive obstruction in children, and tonsil and/or adenoidectomy is the most common treatment for children with SDB. We determined the therapeutic effect of tonsil adenoidectomy on SDB in children with OSAHS and simple snoring by observing the changes in behavioral abnormalities and serum C-reactive protein levels before and after tonsil adenoidectomy. In the OSAHS group, the Conners Behavioral Brief Symptom Questionnaire score decreased from 14.2±3.8 before surgery to 6.7±3.1 after surgery, and the serum C-reactive protein level decreased from (4.25±1.78) mg/L before surgery to (3.23±1.45) mg/L after surgery; in the simple snoring group, the Conners Behavioral Brief Symptom Questionnaire score decreased from 9.4 ± 4.1 before surgery to 5.1 ± 2.8 after surgery, and serum C-reactive protein level decreased from (2.77 ± 1.80) mg/L before surgery to (1.76 ± 0.81) mg/L after surgery Tonsil adenoidectomy was considered to have a significant therapeutic effect on behavioral abnormalities in children with SDB, along with a significant decrease in serum C-reactive protein level [16]. However, the efficacy of surgery is poor in children with small tonsils, narrow epiglottic airway, maxillary hypoplasia, mandibular recession, age less than 12 months, Down syndrome, and neurological deficits. For older patients with small tonsils and adenoids and severe airway obstruction caused by thick and long uvula, uvulopalatopharyngoplasty can be selected at the discretion of the patient after confirmation by fiberoptic nasopharyngoscopy and Muller test. Currently, most tonsillectomies and/or adenoidectomies are performed under general anesthesia with tracheal intubation. Tonsillectomy can be performed by conventional tonsil peeling, electrodebrider tonsillectomy, and low-temperature plasma tonsil ablation. Surgical methods for adenoids include adenoids scraping (blind scraping), which is now generally not commonly used. The most commonly used method is transoral – nasal endoscopy guided adenoids surgery, which has the characteristics of operating under direct vision, clear vision, not easy to damage the surrounding tissues, no residual body, and can avoid adenoids re-proliferation and compensatory hypertrophy after surgery. The specific methods are scraping method: 70° or 110° nasal endoscope (4mm diameter) is placed through the oropharyngeal cavity, and the nasopharyngeal cavity is clearly displayed from the bottom up under the guidance of TV image monitor. Under direct vision, the adenoid scraper is used to remove the hypertrophic adenoid tissue in stages until the pharyngeal orifice of the pharyngeal tube, the posterior margin of the nasal septum, the posterior nostril and the posterior end of the inferior turbinate and other important structures are clearly revealed; the residual tissue around the important structures and the glands protruding into the posterior nostril can be removed with 90° nasopharyngeal biopsy forceps under endoscopic guidance, and after excision, the posterior pharyngeal wall is checked for bleeding and accurate pressure or electrocoagulation is used to stop bleeding. The procedure can be completed with endoscopic guidance. Power system aspiration method: Under direct vision, the adenoids are removed from the posterior nasal aperture with a 45° anterior opening cutting head, and the adenoids are aspirated out while cutting, and hemostasis is achieved by compression or electrocoagulation. The procedure is completed after checking that there is no bleeding in the posterior pharyngeal wall and other areas. Low-temperature plasma adenoid ablation is performed with the Evac70 tip of the low-temperature plasma surgical system under direct vision by ablating the adenoids from the posterior nostril end downward, stopping the hemorrhage while cutting. At present, many large hospitals in China have carried out plasma tonsil and adenoid ablation, and it is believed that plasma surgery has the advantages of short operation time, less intraoperative bleeding, light damage to surrounding tissues, mild local reaction, complete excision, and good efficacy, and is currently recognized as the best surgical method to remove tonsils and adenoids [17]. Zhang Yamei et al [18] analyzed the causes of poor surgical treatment of OSAHS in children, and 17 out of 243 cases had poor results, including 2 cases with tonsillar hypertrophy after adenoidectomy alone, which were cured after reoperation to remove tonsils; 7 cases with concurrent nasal diseases improved after medication; 5 cases with obesity, 1 case of funnel chest, 1 case of cerebral palsy, and 1 case of round occipital hyperplasia were treated with ventilator The symptoms were all significantly relieved by treatment. Therefore, it is evident that surgical removal of the adenoids and/or tonsils is the preferred method for the treatment of OSAHS in children. The poor surgical outcome is mainly due to other complications such as obesity and nasal diseases, but also due to improper selection of indications for adenoidectomy alone. Children with poor surgical results should be carefully analyzed for the reasons and attention should be paid to the treatment of complications, which can further improve the efficacy. However, some experts believe that tonsils are important immune organs in childhood and should not be easily removed in general, except in severe tonsillar hypertrophy causing OSAHS [19]. Tonsillotomy (TT) is an ideal treatment to relieve the symptoms of upper airway obstruction while preserving some of the immune function of the tonsils, but the procedure may lead to complications such as hemorrhage. In recent years, CO2 laser tonsillotomy (CLTT) [20] and plasma ablation tonsillotomy with radiofrequency technique [21] have been used in children because of their low intraoperative bleeding and no postoperative complications. The treatment of OSAHS in children has achieved satisfactory results due to less intraoperative bleeding and no postoperative complications. Compared with conventional tonsillectomy, partial tonsillectomy showed no significant difference in improving behavioral abnormalities and quality of life in children with SDB. Therefore, it is a mildly invasive surgical procedure for children with upper airway obstruction due to tonsillar hypertrophy [22]. Therefore, CO2 laser partial tonsillectomy and plasma radiofrequency ablation partial tonsillectomy can be effective and safe surgical treatments for SDB in children. There are no reports of laser partial tonsillectomy and plasma radiofrequency ablation partial tonsillectomy in China. Li Yuhuan [23] reported partial tonsillectomy using a power cutting system under sinusoscopy, but it did not attract much attention and promotion.
5.2 Conservative medical treatment Many parents have doubts about tonsil and adenoid surgery, especially there are many misunderstandings about the immune function of tonsils, so medical treatment outside of surgery is also a clinical problem that must be faced. Local application of nasal hormone preparations for the treatment of nasal congestion in children with SDB can temporarily partially relieve patients’ symptoms, and systemic antibiotics during the period of upper respiratory tract infection can temporarily A study by Kaditis et al [24] suggested that leukotriene receptor blockers (montelukast) may relieve some of the symptoms in children with SDB.
5.3 Continuous Positive Airway Pressure (CPAP) or Bi-level Positive Airway Pressure (BiPAP) is mainly used for children with congenital dysplasia, cardiopulmonary or muscular disorders and surgically incurable airway obstruction. BiPAP is mainly used for congenital dysplasia, cardiopulmonary or muscular disorders and surgically incurable airway obstruction, including those who cannot undergo tonsil or adenoidectomy or cannot be relieved after surgery, and also for perioperative treatment. Compared with adults, children have a high tolerance rate, and the success rate of CPAP treatment is about 90%, even in infants and children aged 6 months to 2 years, with a good family environment and attentive parental care, good results can be achieved [25]. The success rate of CPAP in children with significant craniofacial deformities is about 62%, and the average treatment pressure of CPAP in prepubertal children is relatively low, with a pressure level of 8 cmH20 being effective in 86% of children. Because children grow rapidly after treatment, careful pressure titration is required for home CPAP or BiPAP use, and treatment pressure and mask size should be routinely followed up and adjusted every 3-6 months to accommodate changes in children’s growth and development, to prevent complications such as mask leakage, gastrointestinal distention, and misaspiration, and to guide and supervise patients to receive treatment.
Others include encouraging obese patients to lose weight and adjusting sleep positions, which are not effective for most severely ill patients. Oxygen can reduce the degree of hypoxia during sleep, but cannot reduce the number of apnea and hypoventilation. For infants and children with moderate OSAS or severe hypoxia but cannot undergo surgery and at the same time cannot tolerate CPAP treatment, simple low-flow oxygenation can help maintain a more normal oxygen level.
6 Conclusion
The population prevalence of childhood SDB is increasing, and OSAHS in children is one of the most dangerous sleep disorders, with nasal congestion, open-mouth breathing, and apnea hypoxia affecting the craniofacial, nasal, growth and intellectual development and behavioral abnormalities of children. Therefore, SDB in children should be diagnosed and treated as early as possible to avoid serious complications. Reasonable and effective treatment can reduce or completely alleviate snoring, apnea, sleep hypoxemia and sleep structure disorders in children, and improve their quality of life.