Multiple pauses in respiration (‘apnoeas’) during sleep, as a result of upper airway collapse, usually at the level of the oropharynx

Aetiology

• Occurs most often in overweight, middle-aged men
• Causes other than obesity include: enlarged tonsils/adenoids, retrognathia, acromegaly, hyperthyroidism, oropharyngeal deformity, neurological (e.g. stroke), drugs (depressants) and anaesthesia (post-op period)

Pathophysiology

• Apnoeas occur when the airway at the back of the throat is sucked closed when breathing in during sleep
• Apnoea leads to hypoxia and increasingly strenuous respiratory efforts until the patient overcomes the resistance
• The combination of central hypoxic stimulation and the effort to overcome obstruction wakes the patient from sleep
• These awakenings are so brief that patients remain unaware of them but may be woken hundreds of times per night, leading to sleep deprivation with consequent daytime sleepiness and impaired intellectual performance

Clinical features

• Excessive daytime sleepiness which majorly impacts daytime function
  • Can be measured using the Epworth Sleepiness Scale
• Lack of concentration
• Loud snoring
• Unrefreshed, restless sleep
• Irritability/personality change

Investigations

• Polysomnography: is the traditional gold standard investigation
  • Other overnight sleep studies - oximetry, domiciliary reading
• Blood pressure

Management

• Correction of treatable factors, including encouraging weight loss and alcohol reduction