Sleep apnoea and neuromuscular respiratory disorders

Question 1

What is obstructive sleep apnoea?

Answer 1

Recurrent episodes of upper airway obstruction leading to apnoea (suspensions of breathing for >10secs) during sleep

Question 2

What are some symptoms of sleep apnoea?

Answer 2

Daytime tiredness due to poor rest
Heavy snoring
Poor daytime concentration
Wake frequently in the night

Question 3

In what groups is obstructive sleep apnoea commonly seen?

Answer 3

Overweight individuals, mostly men

Young children with enlarged tonsils

Question 4

What increases the risk of obstructive sleep apnoea?

Answer 4

Obesity
Alcohol
Hypothyroidism
Acromegaly
COPD

Question 5

Why does sleep apnoea happen at night and not during the day?

Answer 5

Throat muscles become hypotonic and are then more likely to fall and be sucked close

Question 6

What is the prevalence of OSAS?

Answer 6

2% of men and 1% of women

Question 7

How do we diagnose sleep apnoea?

Answer 7

Clinical history and exam
Epworth questionnaire
Overnight sleep studies

Question 8

What is the Epworth questionnaire?

Answer 8

Qs on when people feel sleepy

Question 9

Describe some overnight sleep study tests

Answer 9

Pulse oximetry overnight - O2 sats

Polysomnography - brain waves, O2, HR, RR, eye movements, leg movements, ECG

Question 10

How do classify the severity of OSAS, depending on the number of desaturations during the night (apnoea/hypopnea index):

Answer 10

0-5 = normal
5-15 = mild
15-30 = moderate
>30 = severe

Question 11

What is hypopnea?

Answer 11

Partial apnoea event, airflow to lung reduced for 10 secs

Question 12

How can you treat sleep apnoea?

Answer 12

Continous positive airways pressure (CPAP)

Mandibular repositioning splint

Question 13

What advice should you give to those diagnosed with sleep apnoea?

Answer 13

Lose weight
Reduce alcohol intake
Stop or restrict driving and tell DVLA

Question 14

What is narcolepsy?

Answer 14

Long term neurological disorder that involves decreased ability to regulate sleep-wake cycles. Leads to:

• excessive daytime sleepiness
• cataplexy
• hypnogogic hallucinations
• sleep paralysis
• can be brought on by strong emotions

Question 15

What causes narcolepsy?

Answer 15

Not well known, but a familial link is seen in 10% cases (HLA DRB11501 and DBQ10602)

Question 16

How do you treat narcolepsy?

Answer 16

Modafinil - eugeroic, enhance waking

Clomipramine - cataplexy, TCA
or
Sodium oxybate - if they cant take TCAs

Question 17

What is a complication of sleep apnoea?

Answer 17

Chronic ventilatory failure
Elevated PCO2 and decreased PO2
Normal acid due to build up of bicarbonate

Question 18

What can cause chronic ventilatory failure?

Answer 18

COPD
Bronchiectasis
OSAS
Chest wall deformities e.g kyphoscoliosis
Motor neurone disease
Muscular dystrophy
Obesity hypoventilation syndrome

Question 19

What are the symptoms of chronic ventilatory failure?

Answer 19

Breathlessness
Orthopnoea
Ankle swelling (hypoxic cor pulmonale)
Morning headache
Recurrent chest pain
Disturbed sleep

Question 20

What are some clinical signs of chronic ventilatory failure?

Answer 20

Paradoxical abdominal wall movement in neuromuscular disease
Ankle oedema (hypoxic cor pulmonale)

Question 21

What investigations are used for chronic ventilatory failure?

Answer 21

Lying and standing vital capacity
Stiff nasal inspiratory pressure
Early morning arterial blood gases (ABG)
Overnight oximetry
Transcutaneous CO2 monitoring 
Screening of diaphragm

Question 22

How do you treat chronic ventilatory failure?

Answer 22

Domicillary non-invasive ventilation

Tracheotimised intermittent positive pressure ventilation

Question 23

Describe REM sleep

Answer 23

rapid eye movement phase

paralysis of skeletal muscle, dreaming