Sleep

Question 1

How many stages of slow wave sleep are there?

Answer 1

4

Question 2

What happens to your muscle tone in REM sleep?

Answer 2

No muscle tone

Question 3

What are some sleep disorders associated with non REM sleep?

Answer 3

Confusional arousal
Sleep terror
Sleep walking
*Sleep talking occurs in both non REM and REM

Question 4

What stage of sleep do you enter on falling asleep?

Answer 4

Stage 1 non REM sleep

Question 5

What is normal sleep architecture?

Answer 5

Cycles of stage 1 through to stage 4 then a period of REM sleep
Cycles typically last 90-120 minutes and a night of sleep is made up of 4 or 5 cycles

Question 6

What physiological changes occur in REM sleep?

Answer 6

Peaks of parasympathetic and sympathetic activity
Periods of high HR, RR, BP and ventilation
Decreased thermogenesis
Decreased ventilatory response to hypoxia and hypercapnia due to reduced set points during sleep
Vaginal and penile engorgement

Question 7

What are 3 features of REM sleep?

Answer 7

Inactivity of all voluntary muscles (except extraocular and diaphragm)
Rapid eye movements
Sawtooth waves on EEG

Question 8

What sleep stage takes up the largest amount of sleep time?

Answer 8

Stage 2 non REM sleep

Question 9

Changes in sleep on ageing?

Answer 9

Stage 3/4 sleep decreases
Wake time increases
Stage 1 sleep increases
Total sleep time doesnt change

Question 10

Diagnosis of sleep apnoea?

Answer 10

AHI (apnoea hyponea index) greater then 5 per hour with symptoms
Severe OSA is greater then 30 per hour

Question 11

What is the most common sleep disorder?

Answer 11

OSA

Question 12

Risk factors for OSA

Answer 12

Age, male sex
Obesity - greatest risk factor
Craniofacial abnormalites
smoking
post menopausal
obesity hypoventilation syndrome

Question 13

What medical conditions can OSA occur in?

Answer 13

pregnancy
CHF
Hypothyroidism
ESRF
Chronic lung disease
PCOS
Acromegaly
Stroke/TIA

Question 14

What are the features of an apnoea in OSA?

Answer 14

episode of reduced airflow lasting for 10seconds at least with associated increase in respiratory effort (as seen by increased activity in EMG over chest and abdomen)

Question 15

What is the treatment of OSA?

Answer 15

weight loss

CPAP - provides a splint for the upper airway, minimum starting PEEP 4cmH2O

Question 16

What are some complications of OSA?

Answer 16

Mortality increases by 2-3x
inattention, increased MVA, decreased cognition, depresssion, sexual dysfunction, hypertension, stroke, pul HTN, arrythmias, heart failure, metabolic syndrome, type 2 diabetes

Question 17

What defines obesity hypoventilation syndrome?

Answer 17

obesity BMI greater than 30 with alveolar hypoventilation (pCO2 greater then 35) during waking hours

Question 18

Tests in OHS?

Answer 18

High serum bicarbonate
Low oxygen sats during waking hours
Polycythemia
Hypercapnia and hypoxia on ABG during wakefulness
Normal Aa gradient
PSG - large amount of sleep is spent hypoxic, often increased AHI due to co-comitent OSA

Question 19

What is worse, OHS or OSA?

Answer 19

OSH

• higher mortality
• increased rate of death from PE
• higher rates of CHF and pul HTN

Question 20

Treatment of OHS?

Answer 20

Immediate start of NIV
if OHS alone - start Bipap
if OHS and OSA - start CPAP but if hypercapnia doesnt improve with resolution of apnoeas change to Bipap
Weight loss, bariatric surgery

Question 21

Pathology of narcolepsy?

Answer 21

Loss of Orexin (aka hypocretin)
Orexins are usually released in wakefulness to prevent inappropriate transit into REM sleep
Loss of Orexins allows REM sleep phenomenon to intrude into wakefulness

Question 22

What are the features of narcolepsy?

Answer 22

Excessive daytime sleepiness with sleep attacks
Cataplexy - transient muscle weakness after emotional triggers, consciousness preserved
Hypnagogic hallucinations - vivid frightening hallucinations during falling to sleep
Sleep paralysis
- occurs on awakening unable to move for 1-2 minutes

Question 23

Diagnosis of narcolepsy?

Answer 23

Multiple sleep latency test
- MSLT less then 8 minutes on two naps
PSG confirms into REM sleep on napping (compared to normal - go into stage 1 sleep)
Low CSF Orexin

Question 24

Treatment of narcolepsy?

Answer 24

Stimulants for daytime sleepiness
- modafinil, methylpehnidate
Treatment of cataplexy with medications aiming to increase serotonin and NA e.g SSRIs and SNRIs

Question 25

Treatment of restless legs?

Answer 25

Dopamine agonist (pramipexole, ropinirole)
Gabapentin

Question 26

What is seen on PSG with central sleep apnoea?

Answer 26

AHI greater then 5

Apnoea is lack of airflow for 10 seconds with no respiratory effort