Risk Factors and Pathophysiology
In obstructive sleep apnea, the muscles of the pharynx relax during sleep and allow the airway to collapse, producing repeated apneas and hypopneas with oxygen desaturation and arousals. The strongest risk factor is obesity, along with a large neck circumference, male sex, older age, and craniofacial or upper-airway anatomy. Alcohol and sedatives worsen airway collapse.
Clinical Features
The classic picture is loud snoring, gasping or witnessed apneas reported by a bed partner, and unrefreshing sleep, leading to excessive daytime sleepiness, morning headaches, and impaired concentration. Untreated apnea contributes to hypertension (often resistant), atrial fibrillation and other arrhythmias, and increased cardiovascular and motor-vehicle-accident risk.
Diagnosis
Diagnosis is confirmed with polysomnography (an in-laboratory sleep study) or, in selected patients, home sleep apnea testing. The apnea-hypopnea index (AHI) — the number of events per hour — grades severity as mild, moderate, or severe. Screening questionnaires such as STOP-BANG help identify patients who warrant testing.
Treatment
Continuous positive airway pressure (CPAP) is the first-line treatment for moderate to severe obstructive sleep apnea; it splints the airway open and improves sleepiness, blood pressure, and quality of life when used consistently. Weight loss is important and can be curative, and alcohol and sedatives should be limited. Alternatives include mandibular advancement devices for milder disease and surgery in selected cases.