What are the key clinical features that differentiate central sleep apnea from obstructive sleep apnea in adults?

The provided UK guideline context focuses on Obstructive Sleep Apnoea/Hypopnoea Syndrome (OSAHS) and does not contain information on Central Sleep Apnoea (CSA) or the specific clinical features that differentiate it from OSAHS in adults ¹,².

However, the key clinical features associated with suspected OSAHS in adults include two or more of the following: snoring, witnessed apnoeas, unrefreshing sleep, waking headaches, unexplained excessive sleepiness, tiredness or fatigue, nocturia (waking from sleep to urinate), choking during sleep, sleep fragmentation or insomnia, and cognitive dysfunction or memory impairment ².

OSAHS is defined as a condition where the upper airway narrows or closes during sleep due to muscle relaxation, leading to hypopnoea (under breathing) or apnoea (stopping breathing) ². This can cause disrupted sleep and potentially excessive sleepiness ². A diagnosis of Obstructive Sleep Apnoea Syndrome (OSAS) in adults requires at least five episodes of apnoea, hypopnoea, or both, each lasting a minimum of 10 seconds per hour of sleep ¹.

There is a higher prevalence of OSAHS in people with conditions such as obesity, treatment-resistant hypertension, type 2 diabetes, cardiac arrhythmia (particularly atrial fibrillation), stroke or transient ischaemic attack, chronic heart failure, moderate or severe asthma, polycystic ovary syndrome, Down's syndrome, non-arteritic anterior ischaemic optic neuropathy, hypothyroidism, and acromegaly ².