sleep apnoea syndrome
sleep apnoea syndromeA condition clinically defined by frequent episodes of sleep apnoea, hypopnoea and symptoms of functional respiratory impairment. Sleep apnoea syndrome is potentially life-threatening, and has been associated with daytime hypersomnolence, motor vehicle accidents) and cardiovascular disease (hypertension, stroke, arrhythmias and myocardial infarction); it is more common in the obese and in heavy snorers. 2% of middle-aged females and 4% of males meet the criteria for sleep apnoea syndrome.
Marked alveolar hypoventilation during sleep (despite normal blood-gas levels while awake) due to a failure of autonomic ventilation, resulting in sleep apnoea, arrhythmias and hypertension. Sleep apnoea primarily affects the severely obese (due to tonsillar hyperplasia, relative micrognathia and central apnoea, with loss of the ventilatory drive in the medulla), but may follow bilateral cervical cordotomy used to control intense midline or perineal cancer-related pain (by severing the spinothalamic tract through a ventrolateral incision into the second cervical segment), or may rarely occur in infants; primary hypoventilation is secondary to a loss of CNS chemoreceptor response, which affects men aged 20 to 60.