Obstructive Sleep Apnoea (OSA)

🔍 When to Suspect

Overweight or obese patients reporting excessive daytime sleepiness, loud snoring, and witnessed apnoeas (breathing pauses) during sleep

From the full topic in The Ocean Library: Obstructive Sleep Apnoea (OSA)

🧭 When to suspect

Suspect obstructive sleep apnoea (OSA) in a patient – classically an overweight, middle-aged man – who reports the cardinal triad of loud habitual snoring, witnessed apnoeas (a bed partner describing pauses, gasping or choking during sleep), and excessive daytime sleepiness that persists despite adequate time in bed. Supporting features include morning headache, poor concentration, low mood and nocturia.

It is worth holding two terms apart. OSA describes the breathing events found on a sleep study, whereas obstructive sleep apnoea/hypopnoea syndrome (OSAHS) – sometimes called OSA syndrome – means those events plus daytime symptoms, usually sleepiness. This distinction matters for driving advice, because Driver and Vehicle Licensing Agency (DVLA) duties turn on excessive sleepiness, not on the sleep-study finding alone.

The key primary-care skills are threefold: raise suspicion (including in patients who are not obese), screen and refer for an objective sleep study, and – above all – act first on the sleepy driver. Severity is graded by the apnoea–hypopnoea index (AHI), the number of apnoeas and hypopnoeas per hour of sleep.

AHI (events per hour)	Classification	Typical direction of treatment
< 5	Normal	No OSAHS on this measure
5 to < 15	Mild OSAHS	Lifestyle ± mandibular advancement splint; CPAP if symptomatic and first-line is insufficient
15 to < 30	Moderate OSAHS	CPAP first-line, alongside lifestyle
≥ 30	Severe OSAHS	CPAP first-line; ensure prompt treatment

Raise suspicion most strongly with obesity (especially central, with a large collar size), male sex, middle or older age, and post-menopausal status in women. Other contributors are upper-airway and craniofacial anatomy (retrognathia, micrognathia, macroglossia, enlarged tonsils), alcohol and sedatives, smoking, hypothyroidism, acromegaly and a family history. In children, the commonest cause is adenotonsillar hypertrophy; suspect it with habitual snoring, mouth breathing, restless sleep or behavioural and school difficulties.

Source: NICE NG202

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