obstructive sleep apnoea

Question 1

define

Answer 1

Sleep apnoea is a disorder of breathing during sleep where there is a cessation of airflow lasting at least 10 seconds and is often associated with oxygen desaturation

Question 2

Predisposing factors

Answer 2

• obesity
• macroglossia: acromegaly, hypothyroidism, amyloidosis
• large tonsils
• Marfan’s syndrome
• middle-aged and older men
• abnormalities of the bony and soft tissue structure of the head and neck [large neck 17 inches or more for men, 16 inches or more for women]
• adults and children with Down Syndrome
• children with large tonsils and adenoids
• a family history of OSA

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Aetiological factors include:

1. conditions causing an encroachment on the pharynx
2. conditions causing nasal obstruction
3. drug induced respiratory depression

Question 3

s/s

Answer 3

loud snores

• typically present for many years (often from childhood)
• may be exacerbated following the ingestion of alcohol before bedtime or following an increase in body weight

apnoeic episodes characterized by cessation of breathing/choking episodes

• usually noticed by the bed partner and sometimes he/she may awaken the patient to reestablish the breathing
• termination of the apnoeic event is often associated with loud snores and vocalizations that consist of gasps, moans, or mumblings
• patients are often unaware of these loud snoring and breathing difficulty or of the frequent arousals and brief awakenings that occur throughout the night.

excessive daytime sleepiness

• most common presenting symptom
• causes day time fatigue and concentration difficulties
• occurs when the patient is relaxing e.g. - when sitting, reading or watching television
• in extreme cases patient may fall asleep while actively conversing, eating, walking or driving

in addition there can be symptoms which are commonly observed upon awakening

• feeling unrefreshed
• feelings of disorientation, grogginess, mental dullness, and incoordination

severe dryness of the mouth – often results in patient drinking water during the night or upon waking in the morning

morning headaches – characteristically dull and generalized and often lasts for 1-2 hours

irritability, changes in personality

nocturia

loss of libido

sleep quality of bedpartners may also be affected

Question 4

Assessment of sleepiness

Answer 4

Epworth Sleepiness Scale - questionnaire completed by patient +/- partner

• refer if score >=11*

Multiple Sleep Latency Test (MSLT) - measures the time to fall asleep in a dark room (using EEG criteria)

Question 5

Diagnostic tests

Answer 5

sleep studies - ranging from monitoring of

1. pulse oximetry at night to…
2. full polysomnography where a wide variety of physiological factors are measured including EEG, respiratory airflow, thoraco-abdominal movement, snoring and pulse oximetry

Question 6

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Answer 6

Management

1. weight loss
2. CPAP is first line for moderate or severe OSAHS
3. intra-oral devices (e.g. mandibular advancement) may be used if CPAP is not tolerated or for patients with mild OSAHS where there is no daytime sleepiness
4. limited evidence to support use of pharmacological agents
5. stop smoking