Obstructive sleep apnea (OSA) in children is an increasingly common medical problem, and is associated with many complications, including metabolic, cardiovascular, and neurocognitive changes.
The prevalence of obstructive sleep apnea in children has not been precisely determined since the diagnostic criteria have not been firmly established, but may be increasing in association with the rise in childhood obesity.
Estimates of the prevalence of OSA in children range from 1-4%. Strict numerical criteria for the diagnosis are unsatisfactory, however, and the International Classification of Sleep Disorders Second Edition (ICSD-2) proposes using a combination of signs and symptoms: the AHI and supporting polysomnogram abnormalities such as respiratory effort related arousals, oxygen desaturation, increased end tidal carbon dioxide, or swings in esophageal pressure.
Despite these nosological challenges, studies of OSA in children reveal special features of the disease. For example, snoring is a very common sign, particularly in children ages 2-8. Nasal obstruction, tonsillar hypertrophy, obesity, craniofacial abnormalities, bed-wetting, daytime mouth breathing, daytime somnolence or hyperactivity are all common features. The dental exam may reveal malocclusion, retrognathia, macroglossia, or a long or high arched palate.
A laboratory-based polysomnogram (PSG) is the gold-standard diagnostic test and is generally recommended, but often skipped, before consideration of tonsillectomy and adenoidectomy. The PSG rules for scoring apneas and hypopneas in children are unique, so the scoring technologist must be made aware that the patient is a child. Based on American Academy of Sleep Medicine task force guidelines, the number of apneas and hypopneas per hour (apnea hypopnea index, or AHI) considered abnormal for adults is greater than five. However, studies in children have concluded that one or more apnea per hour is abnormal. Esophageal pressure monitoring may be added to detect swings in intrathoracic pressure, thus improving the sensitivity of the test for detecting respiratory efforts.
Health risks associated with OSA in children are similar to that in adults:
• cognitive behavioral effects
• left ventricular dysfunction
• pulmonary hypertension
• metabolic derangements (e.g., insulin resistance, reduced growth factor and insulin-like growth factor)
Several inflammatory markers are increased as well in children with OSA.
Treatment of Obstructive Sleep Apnea in Children
Tonsillectomy and adenoidectomy are generally considered the first-line treatment if clinically appropriate. Other modalities–often used in combination—successfully alleviate residual OSA in children:
• continuous positive airway pressure (CPAP)
• nasal corticosteroid sprays
• weight loss programs
• orthodontic intervention
At a Glance: Two Recently Published Studies
Cardiovascular Changes in Children with Sleep Disordered Breathing (SDB)
Conducted in Victoria, Australia, this study tested the hypothesis that BP and heart rate are increased during obstructive events in children equivalent to levels reported in adults. The study employed beat-by-beat BP and HR analyzed over the course of obstructive events during NREM and REM sleep. Results showed that BP and HR did increase significantly from late to post event in both sleep states. The study concluded that:
• Children with SDB experience significant changes in HR and BP during obstructive events with magnitudes that are similar to levels reported in adults.
• These changes are more pronounced during NREM sleep and with arousal.
• These acute cardiovascular changes may have important implications for poor cardiovascular outcome, possibly contributing to development of hypertension.
O’Driscoll, D.M. et al, Acute Cardiovascular Changes with Obstructive Events in Children with Sleep Disordered Breathing, SLEEP, 2009; 32 (10):1265-1271
Adenotonsillectomy (AT) impact on Blood Pressure (BP) in Children with OSA
This study, conducted by the Department of Pediatrics, Kwong Wah Hospital, Hong Kong assessed the impact of AT surgery on 24-hour ambulatory BP in children with OSA. Methodology consisted of a retrospective review of records of 44 OSA children who had undergone AT and a repeated sleep polysomnography after AT. Analysis showed that mean AHI dropped after AT. Twenty participants (45%) were cured of OSA. After AT surgery, six out of eight (75%) previously hypertensive children became normotensive. For the pre-AT hypertensive group, both systolic and diastolic BP decreased significantly during sleep after AT. However, eight children who were normotensive before AT became hypertensive after AT (but were more likely to have post-AT AHI >1). The study concluded that:
• 45% were cured of OSA and a significant decrease in BP was achieved after AT.
• Hypertension may persist or occur in previously normotensive children with OSA after AT.
• Cure of OSA should not be assumed after AT and follow-up PSG should be performed together with 24-hour BP monitoring.
Ng, D. K. et al, Ambulatory blood pressure before and after adenotonsillectomy in children with obstructive sleep apnea, Sleep Medicine, 2010; 11 (7): 721–725
Hoban, T.F. and Chervin, R.D., Sleep-related breathing disorders of childhood: description and clinical picture, diagnosis, and treatment approaches, Sleep Med Clin, 2007; 2: 445-462
Katz, E.S. and D’Ambrosio, C.M., Pediatric obstructive sleep apnea syndrome. Clin Chest Med, 2010, 31:221-234.
Bixler, E.O., et al. Sleep disordered breathing in children in a general population sample: prevalence and risk factors. Sleep, 2009; 32(6):731-736
Take Home Points
1. Obstructive sleep apnea affects approximately 1-4 % of children.
2. OSA in children is increasing along with the rise in childhood obesity (close to 20% of 6-19 year olds are obese according to CDC 2008 data).
3. Tonsillectomy and adenoidectomy are the most common first-line treatments of OSA in children. Diagnostic study is recommended to ensure alleviation of sleep disordered breathing.
4. Treatment, sometimes with a combination of methods, produces not only a decrease in the AHI but may also result in improvement in neurocognitive functions and cardiovascular abnormalities.
Melissa S. Lim, MD, is the Medical Director and founder of Redwood Pulmonary Medical Associates. Dr. Lim is board certified in internal medicine, pulmonary diseases, and sleep medicine.