[Physiopathology of obstructive sleep apnea syndrome]

An excellent grasp of the physiopathology of obstructive sleep apnea syndrome (OSAS) is essential to understanding its diagnostic and therapeutic modalities. A systematic review of the literature was performed on data specific to humans. Two aspects are involved: on one hand, the mechanisms contributing to intermittent obstruction of the upper airways (UA) during sleep and, on the other hand, the impact of this obstruction, e.g. neurocognitive disorders, cardiovascular disease and metabolic dysregulation. UA obstruction can be explained by anatomical, mechanical and neuro-functional conditions, especially the proprioceptive and chemical feedback of UA neuromuscular activity. Our understanding of the impact of OSAS has benefited from the recently developed concepts of oxidative stress and low-grade systemic inflammation, the discovery of hypoxia-sensitive agents and of the role of cytokines. The onset of this chain of events is determined by chronic intermittent hypoxia.