36. Sleep Apnoea Flashcards

1
Q

What is obstructive sleep apnoea syndrome?

A

recurrent episodes of upper airway obstruction leading to apnoea during sleep (cessation of breathing)

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2
Q

What is obstructive sleep apnoea usually associated with? (4)

A
  • heavy snoring
  • typically unfresh sleep
  • daytime somnolence/sleepiness
  • poor daytime concentration
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3
Q

What are common causes of repeated closure of upper airway? (3)

A
  1. muscle relaxation
  2. narrow pharynx
  3. obesity
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4
Q

What does repeated closure of upper airway cause? (3)

A
  1. snoring
  2. oxygen desaturation
  3. apnoeas and hypoapnoeas (cessation of breathing for 10 secs or greater)
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5
Q

What do apnoeas and hypoapnoeas often lead to?

A

frequent microarousals (sleep/wake dynamics, brain moving from light to deep sleep)

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6
Q

What do frequent microarousals lead to?(2)

A
  1. poor concentration

2. daytime hypersomnolence

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7
Q

Why is it important to treat obstructive sleep apnoea syndrome? (4)

A
  • impaired quality of life
  • marital dysharmony
  • increased risk of renal tubular acidosis (RTAs)
  • associated with hypertension (increased chance of stroke and heart disease)
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8
Q

How prevalent is obstructive sleep apnoea in men and women?

A

2% of adult men

1% of adult women

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9
Q

How is obstructive sleep apnoea diagnosed? (3)

A
  1. clinical history and examination
  2. epworth questionnaire (assesses how sleepy the person is)
  3. overnight sleep study
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10
Q

What does the overnight sleep study involve? (3)

A
  1. pulse ixumetry
  2. limites sleep studies
  3. full polysomnography
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11
Q

What is the definition of apnoea?

A

simply cessation of breathing for at least 10 seconds; associated with heavy snoring

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12
Q

What are pharyngeal muscles meant to be like when a person is sleeping?

A

They should be relaxed and collapsed to some degree while sleeping; but during apnoea pharynx can be narrowed as fatty tissues around it makes it more likely to close

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13
Q

What score does polysonography needs to get to be classified as excessive sleepiness?

A

at least 11/24 score

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14
Q

What does pulse oximetry measure?

A

non-invasive method of monitoring oxygen saturation in the body (SO2)

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15
Q

When is polysomnography most often used?

A

When there is doubt about sleep apnoea diagnosis (not necessary to be used in most cases)

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16
Q

What does polysomnography measure? (9)

A
  1. oronasal airflow
  2. thoracoabdominal movement
  3. oximetry
  4. body position
  5. EEG (electroencephalogram; activity of brain monitoring)
  6. audivisual recoding
  7. EOG (electrooculography; activity of corneo-retinal standing)
  8. EMG (electromyography; monitors muscles and nerve cells like motor neurones)
  9. ECG (electrocardiogram; measures heart rhythms and electrical activity)
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17
Q

What SO2 desaturation rate is classified as “normal”?

A

0-5

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18
Q

What SO2 desaturation rate is classified as “mild”?

A

5-15

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19
Q

What SO2 desaturation rate is classified as “moderate”?

A

15-30

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20
Q

What SO2 desaturation rate is classified as “severe”?

A

> 30

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21
Q

What are 3 treatment options for sleep apnoea?

A
  1. identify exacerbating factors ( lifestyle measures)
  2. continous positive airway pressure (CPAP); main treatment
  3. mandibular repositioning splint
22
Q

What are common exacerbating factors that should be addressed when treating sleep apnoea? (3)

A
  1. weight reduction
  2. avoidance of alcohol
  3. diagnose and treat endocrine disorders e.g. hypothyrodism, acromegaly
23
Q

What is CPAP? (continuous positive airway pressure)

A
  • Machine that supplies a constant and steady air pressure on inspiration and expiration.
  • generates with positive pressure using a hose mask and a nose piece
24
Q

How does mandibular repositioning splint work?

A

It’s designed to move lower jaw forward creating more space at the back of throat

25
Q

What are the driving regulations for patients with sleep apnoea? (2)

A
  • advise patients with sleep apnoea and excessive daytime somnolence NOT to drive or restrict driving
  • inform DVLA of their condition
26
Q

When should a patient with sleep apnoea be allowed to drive again?

A

Once satisfactorily treated

27
Q

What is nercolepsy?

A

Long-term brain disorder that causes a person to suddenly fall asleep at inappropriate times

28
Q

How prevalent is narcolepsy in a population?

A

0.05%

29
Q

Is narcolepsy familial?

A

yes

30
Q

What 2 genes are associated with narcolepsy?

A
  1. HLA-DRB1 *1501

2. HLA DQB1* 0602

31
Q

What are clinical features of narcolepsy? (4)

A
  1. cataplexy
  2. excessive daytime somnolence/ sleepiness
  3. hypnagogic hallucinations
  4. sleep paralysis
32
Q

What is cataplexy?

A
  • Sudden and transient episode of muscle weakness typically triggered by strong emotions such as laughing, crying or terror.
  • Person collapses on the floor possibly asleep but has full awareness (brain unable to regulate sleeping and waking patterns)
33
Q

What chemical is absent in narcolepsy patients?

A

hypocretin (orexin) which regulates wakefulness

34
Q

What are the treatment options for narcolepsy? (3)

A
  1. modafinil (stimulant for sleepiness)
  2. clomipramine (for cataplexy, antidepressant)
  3. sodium oxybate (Xyrem)
35
Q

What do patients at extreme end of sleep apnoea often develop?

A

chronic ventilatory failure

36
Q

What are the statistics for PCO2, PO2, pH and bicarbonate levels in chronic ventilatory failure?

A
  1. elevated pCO2 (>6kPa)
  2. pO2<8 kPA
  3. normal blood pH
  4. elevated bicarbonate
37
Q

Why is pH at a constant level but bicarbonate levels are elevated?

A

Body will retain bicarbonate in kidneys to buffer excess acid (pH is normal but bicarbonate rises)

38
Q

What are causes (aetiology) for chronic ventilatory failure? (4)

A
  1. airway disease
  2. chest wall abnormalities
  3. respiratory muscle weakness
  4. central hypoventilation
39
Q

What are 3 common airway disease which lead to chronic ventilatory failure?

A
  1. COPD
  2. brochiectasis
  3. OSA; obstructive sleep apnoea (disorder of upper airway)
40
Q

What is a common chest wall abnormality which leads to chronic ventilatory failure?

A

kyphoscoliosis (combination of kyphosis and scoliosis)

41
Q

What are common conditions of respiratory muscle weakness leading to chronic ventilatory failure? (2)

A
  1. motor neurone disease (ALS)

2. muscular dystrophy

42
Q

What are common central hypoventilation syndromes leading to chronic ventilatory failure? (2)

A
  1. obesity hypoventilation syndrome

2. central hypoventilation syndrome (Ondine’s curse)

43
Q

What is the most common cause of central hypoventilation?

A

Obesity (but congenital conditions and sedative drugs can also cause it)

44
Q

What are typical symptoms of chronic ventilatory failure? (6)

A
  1. breathlessness
  2. orthopnoea (dyspnoea when laying flat)
  3. ankle swelling (cor pulmonale causes this)
  4. morning headache
  5. recurrent chest infections
  6. disturbed sleep
45
Q

What do examination findings show in chronic ventilatory failure patients?

A

Reflect underlying disease by looking for:

  • paradoxical abdominal wall motion in suspected neuromuscular disease (weakness in diaphragm which moves in opposite directions)
  • ankle oedema (hypoxic cor pulmonale)
46
Q

What are the 4 investigation steps for neuromuscular disease?

A
  1. lung function
  2. blood count
  3. assessment of hypoventilation
  4. fluoroscopic screening of diaphragms
47
Q

What are 2 lung function tests done for neuromuscular disease?

A
  1. lying and standing VC; vital capacity

2. mouth pressures/SNIP

48
Q

What are 3 assessments of hypoventilation tests done for neuromuscular disease?

A
  1. early morning ABG (arterial blood gas)
  2. overnight oximetry
  3. transcutaneous CO2 monitoring
49
Q

When should CO2 readings be obtained in neuromuscular disease investigation patient?

A

Overnight since patient will hypoventilate during REM sleep especially

50
Q

What does a high ratio of FEV: FVC suggest in a pulmonary function test?

A

restrictive pattern

51
Q

What is the treatment for chronic ventilatory failure? (3)

A
  1. domicillary non-invasive ventilation (NIV)
  2. oxygen therapy
  3. t-IPPV (tracheostomy ventilation)
52
Q

How does Domicillary non-invasive ventilation work (NIV)?

A
  • like CPAP but more sophisticated
  • patient wears mask over nose and when breathing in, the machine will sense it and deliver positive pressure to airway
  • air can be moisturised before breathing in