sleep apnoea and neuromuscular respiratory failure - adults

Question 1

what are the symptoms of obstructive sleep apnoea syndrome?

Answer 1

-recurrent episodes of upper airway obstruction leading to apnoea during sleep
-usually associated with heavy snoring
-typically unrefreshing sleep
-daytime
somnolence/sleepiness
-poor daytime concentration

Question 2

what is the pathophysiology of OSAS?

Answer 2

• muscle relaxation
• narrow pharynx
• obesity

Question 3

what does muscle relaxation, narrow pharynx and obesity lead to in OSAS?

Answer 3

repeated closure of upper airway which will lead to apnoeas and hypopneas

Question 4

what is hypopnoea?

Answer 4

partial apnoeas, shallow breathing and low respiratory rate

Question 5

what do apnoeas and hypopneas lead to during sleep?

Answer 5

microarousals

Question 6

what conditions are at increased risk in patients with OSAS?

Answer 6

hypertension, strokes and probably heart disease

Question 7

should sufferers of untreated OSAS drive?

Answer 7

no as there is an increases risk if RTAs in these people

Question 8

how is OSAS diagnosed?

Answer 8

• clinical history and examination
• Epworth questionnaire
• overnight sleep study

Question 9

give some examples of over night sleep studies

Answer 9

pulse oximetry
limited sleep studies
full polysomnography

Question 10

what is the desaturation rate in a normal person?

Answer 10

0-5 per hour

Question 11

what is the desaturation rate in someone with mild OSAS?

Answer 11

5-15 per hour

Question 12

what is the desaturation rate in someone with moderate OSAS?

Answer 12

15-30 per hour

Question 13

what is the desaturation rate in someone with severe sleep apnoea?

Answer 13

> 30 per hour

Question 14

what are the treatment options for OSAS?

Answer 14

• treating exacerbating factors
• CPAP
• mandibular repositioning splint

Question 15

what are the exacerbating factors of OSAS?

Answer 15

obesity
alcohol
some endocrine conditions, eg. hypothyroidism

Question 16

can narcolepsy be familial?

Answer 16

yes

Question 17

what are the clinical features of narcolepsy?

Answer 17

cataplexy
excessive daytime somnolence
hypnagogic hallucinations
sleep paralysis

Question 18

what are the treatments for narcolepsy?

Answer 18

modafinil
clomipramine
sodium oxybate

Question 19

what does modafinl treat?

Answer 19

sleepiness

Question 20

what does clomipramine treat?

Answer 20

cataplexy

Question 21

what does sodium oxybate treat?

Answer 21

cataplexy

Question 22

what are the characteristics of chronic ventilatory failure?

Answer 22

elevated pCO2 >6.0 kPa
pO2 <8kPA
normal blood pH
elevated bicarbonate

Question 23

what airway diseases can cause chronic ventilatory failure?

Answer 23

COPD
bronchiectasis
OSAS

Question 24

what chest wall abnormalities can cause chronic ventilatory failure?

Answer 24

kyphoscoliosis

Question 25

what conditions causing respiratory muscle weakness can cause chronic ventilatory failure?

Answer 25

motor neurone disease

muscular dystrophy

Question 26

which conditions can cause central hypoventilation which can cause chronic ventilatory failure?

Answer 26

obesity hypoventilation syndrome

central hypoventilation syndrome

Question 27

what are the symptoms of chronic respiratory failure?

Answer 27

breathlessness
orthopnoea
ankle swelling
morning headache
recurrent chest infections
disturbed sleep

Question 28

what are the signs of chronic respiratory failure?

Answer 28

• paradoxal abdominal wall motion inome suspected neuromuscular disease
• ankle oedema (from hypoxic cor pulminale)

Question 29

what are the investigations for chronic respiratory syndrome caused by neuromuscular syndrome?

Answer 29

lung function: lying and standing VC, mouth pressures

assessment of hypoventilation: early morning ABG, overnight oximetry, transcutaneous CO2 monitoring

Question 30

what is the treatment for chronic respiratory failure?

Answer 30

domicillary non invasive ventilation

oxygen therapy