[Obstructive sleep apnea syndrome: Metabolic complications]. / Syndrome d'apnées obstructives du sommeil : complications métaboliques.

Strongly linked to the presence of obesity, the obstructive sleep apnea syndrome is an independent risk factor for abnormalities of glucose metabolism ranging from simple impaired glucose tolerance to type 2 diabetes. It is also a risk factor for dyslipidemia, metabolic syndrome and non-alcoholic fatty liver disease. The pathological mechanisms underlying these associations remain to be precisely discovered, but intermittent hypoxia is probably one of the major factors. The place of obstructive apnea treatment in the management of metabolic conditions remains unclear.

Residual sleepiness in obstructive sleep apnoea: phenotype and related symptoms.

The characteristics of residual excessive sleepiness (RES), defined by an Epworth score >10 in adequately treated apnoeic patients, are unknown. 40 apnoeic patients, with (n = 20) and without (n = 20) RES, and 20 healthy controls underwent clinical interviews, cognitive and biological tests, polysomnography, a multiple sleep latency test, and 24-h sleep monitoring. The marked subjective sleepiness in the RES group (mean ± sd score 16.4 ± 3) contrasted with moderately abnormal objective measures of sleepiness (90% of patients with RES had daytime sleep latencies >8 min). Compared with patients without RES, the patients with RES had more fatigue, lower stage N3 percentages, more periodic leg movements (without arousals), lower mean sleep latencies and longer daytime sleep periods. Most neuropsychological dimensions (morning headaches, memory complaints, spatial memory, inattention, apathy, depression, anxiety and lack of self-confidence) were not different between patients with and without RES, but gradually altered from controls to apnoeic patients without and then with RES. RES in apnoeic patients differs markedly from sleepiness in central hypersomnia. The association between RES, periodic leg movements, apathy and depressive mood parallels the post-hypoxic lesions in noradrenaline, dopamine and serotonin systems in animals exposed to intermittent hypoxia.

[Which complementary studies and metabolic monitoring must be performed in OSAS? For which patients?]. / Quel bilan et quel suivi métabolique doit-on faire dans le SAHOS? Pour quels patients?

Characterised by abnormal breathing during sleep, obstructive sleep apnea (OSA) is strongly associated with obesity. Visceral obesity is a component of metabolic syndrome with insulin resistance, hypertension and dyslipidemia. OSA may also represent an independent risk factor for cardiovascular disease, especially hypertension, diabetes mellitus and dyslipidemia. Abdominal adiposity is an important factor for the development of OSA and associated metabolic disorders. Diagnosis of metabolic syndrome can be made using usual markers like waist circumference, arterial pressure measurement, fasting blood glucose, fasting cholesterol, triglyceride and HDL-cholesterol. Those parameters should be systematically evaluated in case of OSA.