Executive summary of respiratory indications for polysomnography in children: an evidence-based review

Classification of sleep disorders

The classification of sleep disorders is necessary to discriminate between disorders and to facilitate an understanding of symptoms, etiology, and pathophysiology that allows for appropriate treatment. The earliest classification systems, largely organized according to major symptoms (insomnia, excessive sleepiness, and abnormal events that occur during sleep), were unable to be based on pathophysiology because the cause of most sleep disorders was unknown. These 3 symptom-based categories are easily understood by physicians and are therefore useful for developing a differential diagnosis. The International Classification of Sleep Disorders, version 2, published in 2005 and currently undergoing revision, combines a symptomatic presentation (e.g., insomnia) with 1 organized in part on pathophysiology (e.g., circadian rhythms) and in part on body systems (e.g., breathing disorders). This organization of sleep disorders is necessary because of the varied nature and because the pathophysiology for many of the disorders is still unknown. The International Classification of Sleep Disorders, version 2 provides relevant diagnostic and epidemiological information on sleep disorders to more easily differentiate between the disorders.

Childhood obesity and obstructive sleep apnea

The global epidemic of childhood and adolescent obesity and its immediate as well as long-term consequences for obese individuals and society as a whole cannot be overemphasized. Obesity in childhood and adolescence is associated with an increased risk of adult obesity and clinically significant consequences affecting the cardiovascular and metabolic systems. Importantly, obesity is additionally complicated by obstructive sleep apnea (OSA), occurring in up to 60% of obese children. OSA, which is diagnosed using the gold standard polysomnogram (PSG), is characterised by snoring, recurrent partial (hypopneas) or complete (apneas) obstruction of the upper airway. OSA is frequently associated with intermittent oxyhemoglobin desaturations, sleep disruption, and sleep fragmentation. There is emerging data that OSA is associated with cardiovascular burden including systemic hypertension, changes in ventricular structure and function, arterial stiffness, and metabolic syndromes. Thus, OSA in the context of obesity may independently or synergistically magnify the underlying cardiovascular and metabolic burden. This is of importance as early recognition and treatment of OSA in obese children are likely to result in the reduction of cardiometabolic burden in obese children. This paper summarizes the current state of understanding of obesity-related OSA. Specifically, this paper will discuss epidemiology, pathophysiology, cardiometabolic burden, and management of obese children and adolescents with OSA.