Sleep disorders

Question 1

When (during the night) do non-REM parasomnias occur?

what about REM sleep disorders?

Answer 1

Throughout the night, the non-REM sleep becomes less in duration, and REM becomes more

therefore, the early night is more typical for non-REM parasomnia (sleep walking, and patients can’t recall what’s going on, first third of night, family history and school age onset)

and REM is more common later in the evening (in the elderly, this is more aggressive lashing out in the sleep, and is closer to the bedside)

Question 2

What is the Arousal Index?

Answer 2

this is the number of EEG recorded arousals per hour of sleep

Question 3

What is the Respiratory Disturbance Index?

Answer 3

This is the number of complete or partial pauses in respiration per hour of sleep

Question 4

What is narcolepsy?

Answer 4

Sleep collapses

there is an associated cataplexy in 2/3 (sudden bilateral loss of tone associated with high emotion)

In Narcolepsy there is apparently a decreased of CSF Orexin/Hypocretin, which is a hormone that keeps the body in its current state of being

Question 5

What is a stimulatory test that we can do to prove/disprove narcolepsy?

Answer 5

a multiple sleep latency test

• keep a person over night for a sleep study, then let them nap at 4 times during the day.

you have to record how long it takes them to get to sleep, and also how often they go into REM sleep

in narcolepsy, they go to sleep too fast, and can also have too much REM sleep

Question 6

how do you diagnose OSA?

what are the levels of severity?

Answer 6

It must be on a sleep study

normal is 30 events/hr

Question 7

What is the Obstructive Sleep Apnoea Hypopnoea Syndrome?

Answer 7

This is a syndrome where the patient must fulfil:

1. excessive daytime sleeping that is not better explained by other factors
OR
2. two or more factors that are not better explained by other factors
- choking
-recurrent waking
-unrefreshing sleep
-daytime fatigue
-impaired concentration

AND MUST HAVE:
sleep study demonstrating at least 5 events/hour (they can be obstructive apnoeas or hyponoeas)

Question 8

Is there any evidence of OSAHS causing hypertension?

Answer 8

There is a number of good studies that demonstrate OSAHS can be associated with systemic hypertension

Treatment of OSAHS led to decrease in MAP of 2-5mmHg over 2 months in HTN patients

Question 9

is there any increased risk of MVA with OSAHS?

Answer 9

there is an approximate 2-7 times control rates, but all the studies had methodological flaws

and it seems to be highest risk in those with severe disease

Question 10

Who should receive CPAP for their OSAHS?

Answer 10

There have been a few studies that have shown that patients have to be symptomatic to see a benefit.

It has been shown to help patients with mild OSA, with symptoms, but also not help those with SEVERE and ASYMPTOMATIC

Question 11

are mouth guards (called oral appliances) any good, or are they quack medicine?

Answer 11

apparently they have been shown to be useful in mild-mod OSA (5 - 30 events/hour)

not severe though

Question 12

are there any lifestyle measures that can improve OSAHS?

Answer 12

yes, losing weight is very important

Question 13

what causes Cheyne Stokes breathing?

Answer 13

classically heart failure, although, it is also a pre-terminal thing

Question 14

Is there any reason that a person with severe COPD would have three - four periods of falls in SpO2?

Answer 14

There is a REM period called “phasic REM” where there is abnormality in heart and resp rate

this can lead to significant reductions in tidal volume (up to 40%)

in patients without any resp reserve, this can lead to significant desaturations (and elevation of CO2)

Question 15

In someone with severe OSA on sleep study, who is over weight:

which of the following is he at greatest risk of? (compared to someone without OSA)

1. stroke
2. MVA
3. MI
4. HTN

Answer 15

1 - the evidence is still being gathered

2- yes, the increase is about 2 - 7 fold increase

3 - evidence is still being gathered

4 - increase is about 2 fold.

Overall, “fall asleep accident” is the highest risk, then hypertension

Question 16

what is the strongest predictor for compliance with CPAP?

Answer 16

symptoms / symptom improvement with treatment

Question 17

what is the best test for a teenager with falling asleep at school and a normal sleep study?

Answer 17

this is concerning for narcolepsy.

the best test for narcolepsy is multiple sleep latency test

Question 18

During a polysomnogram, what is happening to the abdominal/thoracic readings during an apnoea? (in a patient with OSA)

what about Cheyne-Stokes?

Answer 18

the characteristic finding is persistent effort from the muscles of respiration, but no movement of air at the mouth/nose

with Cheyne-Stokes breathing, there is complete absence of effort. (Everything goes flat)

Question 19

what is delayed sleep phase syndrome?

Answer 19

it’s a primarily teenage condition where they go to bed later and later.

the treatment is “bright light therapy”

which is another way of saying, “shine a bright light on them when they wake up”