[The sleep apnea syndrome. A general review]

During the last years, medical interest has focused on sleep related diseases, especially the sleep apnea syndrome (SAS) and the nocturnal breathing abnormalities associated with broncho-pulmonary diseases. It now appears that SAS is far more prevalent than previously believed. In this review article we present the clinical features, the investigations and the current therapeutic methods. We also discuss the recent developments in our understanding of the SAS pathophysiology and their implications in the disease's management. Clinical importance of sleep related disorders of breathing is appreciated when one looks at some of the secondary effects including hypertension, angina pectoris, cardiac insufficiency and worsening of a broncho-pulmonary disease (hypoxemia, hypercapnia); these are associated with a high degree of morbidity. The recent advent of ambulatory screening systems allows an easier evaluation of patients at risk, such as obese or hypertensive snorers and patients with hypersomnolence; then the diagnostic polysomnographic studies can be reserved for subjects in whom home recording is abnormal. A precise and early diagnosis is important to allow the initiation of treatment such as Continuous Positive Airway Pressure (CPAP) or naso-pharyngeal surgery.