[Obstructif sleep apnea-hypopnea syndrome: evolution of an old concept]

This review summarizes the well-known clinical features of the obstructive sleep apnea-hypopnea syndrome (OSAHS) and emphasizes new research on this syndrome. Though described in the seventies, the prevalence OSAHS is known mainly in the US. A dramatic increasing in prevalence has been related to the increase prevalence of obesity, raising a substantial public health problem. Discussion continues on the proper definition of the syndrome and degrees of severity. Multiple factors are involved in the pathogenesis of sleep apnea: anatomic abnormalities, mechanical factors, nervous alterations, muscular imbalance between pharyngeal constrictor and dilator muscles or part of a metabolic syndrome? Indeed, obstructive sleep apnea with and without obesity is increasingly implicated in the initiation and progression of metabolic disorders and of cardiovascular diseases (hypertension, cardiac ischemia and probably congestive heart failure, cardiac arrhythmias and strokes). An extended literature reports the neural, humoral, thrombotic, metabolic and inflammatory mechanisms linking OSAHS to endocrinology and cardiovascular diseases. Daytime sleepiness, cognitive, memory and performance deficits with their risks are also stressed. These consequences require treating this syndrome as soon as possible. Multiple interventions (medical, mechanical-nasal positive airway pressure or oral appliances, and sometimes surgical management) can be used but nasal continuous positive airway pressure is the "gold standard" treatment in severe OSAHS. More often multiple interventions are appropriate in a given patient. Finally, there is growing evidence that genetic factors influence the expression of OSAHS. Numerous genetic studies have investigated the etiology of OSAHS with the goal of improving our understanding of its pathogenesis.