Sleep Disorders

Question 1

What are the causes of daytime sleepiness

Answer 1

1. Lifestyle: poor sleep hygiene
2. Sleep breathing disorders
3. Drugs and alcohol
4. Idiopathic hypersomnia

These are considered Tiredness/lethargy, not sleepiness:
• RLS/Periodic limb movement disorder
• Insomnia and circadian disorders
• Narcolepsy
• Postviral (tiredness and fatigue)

Question 2

How is sleepiness different to tiredness or lethargy?

Answer 2

Sleepiness will fall asleep (e.g. sitting in front of TV)

Tiredness or lethargy will not fall asleep when resting

Question 3

What scoring system is used to assess sleepiness?

Answer 3

Epworth Sleepiness score

How likely are you to fall asleep in contrast to just feeling tired

Question 4

What respiratory control changes happen at the onset of sleep?

Answer 4

1. loss of wakefulness drive to breathe and behaviours influences
2. several other resp control mechanisms are down-regulated (respiratory reflexes, chemosensitivity, upper airway and resp pump muscle tone)
3. Chemical control is the major regulator of breathing during sleep

Question 5

What are the two types of sleep apnoea?

Answer 5

Obstructive and Central

Question 6

What the cardinal symptoms of obstructive sleep apnoea?

Answer 6

Cardinal:
Heavy snoring
Excessive daytime somnolence
Witnessed apnoeas

Question 7

What are some other nocturnal and daytime symptoms?

Answer 7

Nocturnal:

• Disrupted, restless, unrefreshed sleep
• Nocturia
• Nocturnal choking, gasping

Daytime:

• headaches
• Memory impairment
• Mood disturbance
• Uncontrolled HTN (if marked O2 desaturation)

Question 8

What are the risk factors of OSA?

Answer 8

• Age (with age the muscles relax more)
• Male gender (males have more collapsable throats)
• Obesity (there is internal fat deposits in the lateral pharyngeal walls, therefore narrow upper airways)
• Alcohol or sedatives (makes upper airway muscle more)
• Upper airway morphology including nasal obstruction (e.g. blocked nose)

Question 9

What Ix do we use to diagnose sleep apnoea?

Answer 9

Sleep studies: can see when patient is breathing and not breathing

Central v Obstructive Apnoea
The main difference between central and obstructive is that in central there is no effort to breathe as the respiratory centre is not working
In OSA, the chemical feedback induces a will to breathe

Question 10

How do we diagnose sleep apnoea?

Answer 10

AHI > 5 events per hour (events/total sleep time)

• > apnoea: complete cessation of airflow for 10 seconds or longer regardless of oxygen destauration
• > hyponoea: 30% or more reduction in airflow associated with >/= 3% oxygen desaturation or an alpha wave arousal from sleep (small drops in ventilation)

Question 11

How do we manage OSA?

Answer 11

When to treat depends on how much the day time sleepiness is bothering the patient.

• Conservative treatments: weight loss, avoid alochol, tobacco and sedatives, body position (lying on the side) treat nasal congestion, treat medical disorders like hypothyroidism)
• CPAP: increases the pressure throughout the respiratory tract (does not breathe for you i.e. not a biPAP or vPAP)
• Oral appliances: if failed CPAP treatment, it pulls the lower throat forward to prevent collapse of upper airway
• Surgery: in adults, surgery does not work well therefore not first line

Two standard treatments for sleep apnoea: WEIGHT LOSS AND CPAP

Question 12

Ask about sleep apnoea in a pt if the look like

Answer 12

Fat neck, short neck

Question 13

What is central sleep apnoea?

Answer 13

Apnoeas or hyponoeas caused by a loss of central respiratory drive

Question 14

Causes of central sleep apnoea

Answer 14

• Cardiac failure
• High altitude: everyone will get central sleep apnoea if high enough, low oxygen level breathes harder and hyperventilating therefore CO2 levels low. When sleep the CO2 increases as you blow off less, then start breathing again, etc.
• CNS disorders (CVA)
• Idiopathic