Obstructive Sleep Apnea

Question 1

how can you make a diagnosis of sleep apnea?

Answer 1

• history from relatives (silence score cycle)
• epworth sleepiness scale
• overnight pulse oximetry (sats fall in cyclical manner and give sawtooth appearance on trace)
• full polysomnographic studies-rarely needed for clinical diagnosis
• diagnosis with more than 10-15 apneas or hypoapneas in 1 hour of sleep

Question 2

what is the management of sleep apnea?

Answer 2

• correct treatable factors
• nasal continuous positive pressure airway pressure-face mask
• nasal CPAP to improve symptoms (half patients can’t tolerate CPAP)
• modafimil

Question 3

what is used to determine sleep apnea from snoring?

Answer 3

epworth sleepiness scale

Question 4

Describe the Epworth sleepiness scale?

Answer 4

asks patients to grade how likely they are to fall asleep in certain situations (0-not at all to 3-high chance of dosing?

Question 5

what situations are asked about in the Epworth sleepiness scale?

Answer 5

• sitting and reading
• watching TV
• sitting, inactive in public place
• passenger in hour long car journey
• lying down to rest in afternoon
• sitting after lunch
• in car, stopped at traffics

Question 6

what is normal, severe obstructive sleep apnoea and narcolepsy on the epworth sleepiness scale?

Answer 6

normal = 5 (+/-4)
severe obstructive sleep apnoea = 16 (+/-4)
narcolepsy = 17

Question 7

what is the difference in inspiration between a normal person and a patient with sleep apnea

Answer 7

during inspiration there is drop in pressure as air is sucked through the turbinates. in patients with obstructive sleep apnoea this collapses the pharynx to obstruct inspiration

Question 8

what are the symptoms of obstructive sleep apnea (order most to least common)?

Answer 8

loud snoring
daytime sleepiness
unrefreshed sleep
restless sleep
morning headache
nocturnal chocking
reduced libido
morning drunkenness
ankle swelling

Question 9

what are the correctable factors contributing to obstructive sleep apnea?

Answer 9

• encroachment on pharynx (obesity, acromegaly, enlarged tonsils)
• nasal obstruction (nasal deformities, rhinitis polyps, adenoids)
• respiratory depressant drugs (alcohol, sedatives, strong analgesics)

Question 10

what is the prevelance of sleep apnea?

Answer 10

1-2%

Question 11

who does obstructive sleep apnea most frequently affect?

Answer 11

overweight middle aged men

Question 12

describe the pathophysiology of sleep apnea?

Answer 12

• in REM sleep activity of respiratory muscles reduced (diaphragm is virtually the only active muscle)
• apnea occurs when airway at back of throat is sucked closed when breathing.
• when awake this is overcome by action of opening muscles of upper airway (during sleep these are hypotonic)
• leads to hypoxia and increasingly strenuous respiratory effort until patient overcomes resistant

Question 13

what are the differences between snoring, apneas and hypoapneas?

Answer 13

snoring=partial narrowing
apnoea=complete occlusion
hypoapnoeas=critical narrowing

Question 14

during sleep apnea what wakes the patient from sleep?

Answer 14

combination of central hypoxic stimulation and effort to overcome obstruction

Question 15

describe the awakenings patients with sleep apnea experience?

Answer 15

so brief that the patient remains unaware of them but may be woken hundred of times per night causing sleep deprivation, reduction in REM and daytime sleepiness