[Obstructive sleep apnea in children--pathophysiology update].

The obstructive sleep apnea syndrome (OSAS) is a common and potentially serious problem during childhood. Airway obstruction during sleep may occur due to narrowed bony passages in conditions such as congenital craniofacial anomalies or in the collapsible segments of the upper airways (naso/hypo pharynx). Adenotonsillar hypertrophy has been considered as the main and most important causative factor for OSAS in the pediatric population. However, adenotonsillar hypertrophy is not the sole cause for this syndrome. Normal infants and children have relatively narrowed upper airways. They maintain airway patency during sleep by increasing the upper airway neuromotor tone and adjusting central ventilatory drive. Recent studies suggest that childhood OSAS is a dynamic process resulting from a combination of structural and neuromotor abnormalities, rather than from structural abnormalities alone. Genetic factors have also been suggested. This review delineates the current concepts of the pathophysiology of OSAS in infants and children.