Sleep disordered breathing

Question 1

Sleep apnoea

Answer 1

Recurrent upper airway obstruction during sleep, sufficient to cause sleep fragmentation and daytime sleepiness. Characterised by irregular breathing and snoring patterns - which can cause a person to momentarily stop breathing in their sleep.

Question 2

What causes sleep apnoea?

Answer 2

Sleep apnoea results from recurrent occlusion of the pharynx during sleep, usually at the level of the soft palate.

Question 3

What are risk factors for sleep apnoea?

Answer 3

Predisposing factors to the sleep apnoea/hypopnoea syndrome include male gender, which doubles the risk, and obesity, which is found in about 50% because parapharyngeal fat deposits tend to narrow the pharynx. Nasal obstruction or a recessed mandible can further exacerbate the problem. Acromegaly and hypothyroidism also predispose by causing submucosal infiltration and narrowing of the upper airway.

Question 4

What are symptoms of sleep apnoea?

Answer 4

Sleep deprivation
Depression / Irritability.
Nocturia
Increased blood pressure and heart rate (arterial fibrillation).

Question 5

What could cause a blockage of the airway that may cause sleep apnoea?

Answer 5

Obesity
Swollen adenoids
Overbite
Allergies

Question 6

Why do apnoea problems present more at night?

Answer 6

Hormonal changes at night cause the muscles around the airway to become slightly less stiff while sleep. This means they’re less likely to keep the airway open - more likely to be squashed / obstructed.

Question 7

Central sleep apnoea is a problem with where?

Answer 7

The central nervous system

Question 8

Explain the process of central sleep apnoea.

Answer 8

This is where the brain intermittently stops making an effort to breathe for 10 to 30 seconds.

The apnea can persist for several seconds even after waking up, triggering feelings of panic and further disrupting the sleep cycle.

Central sleep apnea starts with an initial episode of hyperpnea, which is when the brain directs the lungs to start hyperventilating during sleep by increasing the respiratory rate.

This rapid breathing causes hypocapnia, a drop in the blood’s carbon dioxide levels.

When the carbon dioxide falls below a certain threshold, the body slips into a state of apnea, making no effort to breathe and taking in no oxygen.

This causes the carbon dioxide levels to rise back to normal levels and then, as the apnea persists, they keep rising to which is called hypercapnia.

Question 9

Summarise the process of central sleep apnoea.

Answer 9

Essentially, the respiratory system is going rapidly back and forth between two states, first making no effort to breathe and then hyperventilating.

Question 10

What is the most common symptom of sleep apnea?

Answer 10

Sleep deprivation.

Question 11

What complications occur with sleep apnoea?

Answer 11

Worsens other problems:

The decrease in oxygen can lead to anginal chest pain, and can irritate heart cells leading to an arrhythmia.

Question 12

What does sleep apnoea act as a risk factor for?

Answer 12

Respiratory failure
Cardiac failure
Diabetes
Types of cancer
Car crashes due to sleep deprivation.

Question 13

How is sleep apnoea diagnosed?

Answer 13

Diagnosed with a sleep study - identifies episodes of sleep apnea.

Question 14

How does a sleep study work?

Answer 14

Involves monitoring overnight with a polysomnogram.

Question 15

What does a polysomnogram track?

Answer 15

Vital signs
O2 and CO2 levels
Brain movement
Outward symptoms e.g snoring / movement

Question 16

How is sleep apnoea treated?

Answer 16

Avoiding sleep medications, alcohol and depressant medication as they can relax the throat muscles around the airways.
Sleeping on the side as it creates better airflow into the lungs.
Continuous positive airway pressure device.
Treat underlying conditions.
Weight loss and stopping smoking
Surgery

Question 17

Two forms of sleep apnoea?

Answer 17

Physical obstruction of the airway

Neurological malfunction initiated by imbalances in the blood’s oxygen and carbon dioxide levels, which regulate breathing cycles.

Question 18

OSAS - obstructive sleep apnoea syndrome

Answer 18

Thus obstructive sleep apnoea syndrome is:-
• Pharyngeal incompetence – sleep related muscle
relaxation - fails to overcome closing forces
• Recurrent brief arousal from sleep to clear the
airway, thus markedly fragmented sleep
• Daytime consequences of sleep fragmentation,
mainly excessive daytime sleepiness

Question 19

Narcolepsy

Answer 19

Excessive sleepiness due to a neurological condition caused by failure of neurotransmission in a tiny subset of brain neurons.

Question 20

A decrease is what neuropeptides causes narcolepsy?

Answer 20

Orexin 1 Orexin 2

aka Hypocretin 1 Hypocretin 2

Question 21

What are the functions of orexins / hypocretins?

Answer 21

These orexins increasing the activity of wake-promoting regions of the brain, and prevent inappropriate transitions into a sleeping state.

Question 22

What is thought to be the pathology of narcolepsy?

Answer 22

An autoimmune condition is thought to damage the neurons that deliver orexin.

Question 23

When does the onset of narcolepsy occur?

Answer 23

Adolesence

Question 24

What are the four key symptoms of narcolepsy?

Answer 24

Sleep attacks - feeling chronically sleepy
Cataplexy
Hypnogogic hallucinations

Question 25

What is cataplexy?

Answer 25

When strong emotions trigger muscle weakness / paralysis.

Question 26

What are hypnogogic hallucinations?

Answer 26

Vivid and often frightening visual, tactile, or auditory hallucinations that occur as the patient is falling asleep. They probably result from a mixture of wakefulness and the dreaming of REM sleep.

Question 27

Hyponopompic hallucinations

Answer 27

Hypnopompic hallucinations are similar to hypnogogic except that they occur upon awakening; although these are less common, they can happen to people with narcolepsy.

Question 28

Sleep paralysis

Answer 28

Inability to move after waking or before sleeping.
> brain is active but voluntary muscles are paralysed.
> accompanied by hypnopompic hallucinations (frightening).

Question 29

How is narcolepsy diagnosed?

Answer 29

Polysomnogram
History of cataplexy
Multiple sleep latency testing

Question 30

What are the 3 criteria for insomnia?

Answer 30

1. Having difficulty falling asleep, or waking up throughout the night or in the early-morning and then struggling to fall back asleep.
2. The disturbance must be present for more than three times a week for at least three months.
3. Affects individuals life e.g performance at work

Question 31

Where does the muscle weakness classicly affect in cataplexy?

Answer 31

That muscle weakness is often partial, affecting the face, neck, and knees, but severe episodes can cause total body weakness or paralysis, causing the person to collapse.

Question 32

What are the three conditions categorised by parasomnia?

Answer 32

Nightmare sleep disorder
NREM arousal disorder
REM sleep behaviour disorder

Question 33

What are parasomnias?

Answer 33

Abnormal behaviours, experiences and feelings whilst sleeping, during specific sleep stages or as one wakes up.

Question 34

Explain NREM arousal disorder.

Answer 34

When an individual partially wakes up during the first third of the night during stage 3 - can be seen on polysomnography.
People sleep walk or experience sleep terrors when they wake up.
People cannot recall the episode and instead present as chronically fatigued.

Question 35

Explain nightmare sleep disorder.

Answer 35

Frequent nightmares that involve disasters and feeling unsafe.
> people often awake from the nightmare feeling orientated and alert.

Question 36

Explain REM sleep disorder.

Answer 36

People move a lot whilst sleeping, reenacting violent nightmares - risk of hurting oneself.
> diagnosed with a polysomnogram

Question 37

Explain restless leg syndrome.

Answer 37

Urge to keep moving legs

> starts when the individual sits still and is relieved by movement.

Question 38

What is akathisia?

Answer 38

Akathisia is a condition that causes a feeling of restlessness and an urgent need to move.
> side effect of some antipsychotics.

Question 39

What is the treatment for restless leg syndrome?

Answer 39

Treatment is iron, reducing caffeine or drugs and then

antiparkinson drugs in low doses.

Question 40

Oximetry

Answer 40

A pulse oximeter is a medical device that indirectly monitors the oxygen saturation of a patient’s blood - used to test for sleep apnea.

Question 41

CPAP

Answer 41

Continuous Positive Airway Pressure - used to treat sleep apnea by keeping the airway open.