Sleep Apnoea and Neuromuscular Respiratory Failure

Question 1

What is obstructive sleep apnoea syndrome ?

Answer 1

Recurrent episodes of upper airway obstruction leading to apnoea during sleep

Question 2

What is the presentation of OSAS ?

Answer 2

Usually associated with heavy snoring
Typically unrefreshing sleep
Daytime somnolence/ sleepiness
Poor daytime concentration

Question 3

What is primary snoring ?

Answer 3

Snoring without apnoea, hypoventilation, hypoxia, hypercapnea, daytime symptoms

Question 4

What is OSAS associated with ?

Answer 4

Impaired QoL
Marital disharmony
Increased risk of RTAs
Associated with hypertension, increased risk of stroke and increased risk of heart disease

Question 5

What is the prevalence of OSAS ?

Answer 5

2% adult men

1% adult women

Question 6

How is OSAS diagnosed ?

Answer 6

Clinical history and examination
Epworth questionnaire
Overnight sleep study:

Question 7

What is involved in an overnight sleep study ?

Answer 7

Pulse oximetry
Limited sleep studies
Full polysomnography

Question 8

What is the Epworth sleepiness scale ?

Answer 8

0- would never dose
1- slight chance of dozing
2- moderate chance of dozing
3- high chance of dozing

Question 9

When is the Epworth scale abnormal ?

Answer 9

a score >/= 11

Question 10

What is overnight oximetry ?

Answer 10

Probe on end of finger

Records saturation of O2

Question 11

What is polysomnography ?

Answer 11

Oronasal airflow
Thoracoabdominal movement
Oximetry
Body position
EEG
EOG
EMG (peripheral muscle)
ECG

Question 12

What is the OSA severity ?

Answer 12

Desaturation rate/ AHI:

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

Question 13

What is the treatment for OSAS

Answer 13

Identify exacerbating factors:
- weight reduction
- avoidance of alcohol
- diagnose and treat endocrine disorders e.g. Hypothyroidism acromegaly
Continuous positive airways pressure (CPAP)
Mandibular repositioning splint

Question 14

What is the regulations for driving with someone with OSAS ?

Answer 14

Advise pateints with sleep apnoea and excessive daytime somnolence not to drive or restrict driving and to inform DVLA of condition
Once satisfactory treated should be allowed to drive

Question 15

What is narcolepsy ?

Answer 15

a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep.

Question 16

What is the prevalence of narcolepsy ?

Answer 16

0.05%

Question 17

What is narcolepsy associated with ?

Answer 17

HLA-DRB1*1051

HLA DQB1*0602

Question 18

What are the clinical features of narcolepsy ?

Answer 18

Cataplexy
Excessive daytime sleepiness
Hypnagogic/ hypnopompic hallucinations
Sleep paralysis

Question 19

What are the investigations of narcolepsy ?

Answer 19

Polysomnography
MSLT (multiple sleep latency test)
Low CSF orexin

Question 20

What is the treatment for narcolepsy ?

Answer 20

Modafinil
Dexamphetamine
Venlafaxine
Sodium oxybate (xyrem)

Question 21

What is chronic ventilatory failure ?

Answer 21

Condition that results in the inability to effectively exchange carbon dioxide and oxygen

Question 22

What are the features of CVF ?

Answer 22

Elevated pCO2 (>6kPa)
pO2 <8kPa
Normal blood pH
Elevated bicarbonate

Question 23

What are the causes of CVF ?

Answer 23

Airways disease:
          - COPD
          - bronchiectasis 
Chest wall abnormalities:
          - kyphoscoliosis 
Respiratory muscle weakness:
          - motor neurones disease (ALS)
          - muscular dystrophy 
          - glycogen storage disease (pompe's disease)
Central hypoventilation:
          - obesity hypoventilation syndrome
          - congenital central hypoventilation syndrome (Ondine's curse)

Question 24

What are the typical symptoms of CVF ?

Answer 24

Breathlessness
Orthopnoea 
Ankle swelling
Morning headache
Recurrent chest infections
Disturbed sleep

Question 25

What are the typical examinations findings for CVF ?

Answer 25

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

Question 26

What are the investigations for CVF ?

Answer 26

Lung function:
       - lying and standing VC
       - mouth pressures. SNIP
Assessment of hypoventilation:
       - early morning ABG
       - overnight oximetry
       - transcutaneous CO2 monitoring 
(fluoroscopic screening of diaphragms)

Question 27

What is the treatment for CVF ?

Answer 27

Non-invasive ventilation

O2 therapy