Sleep Apnoea and Neuromuscular Respiratory Disorders

Question 1

What is obstructive sleep apnea syndrome?

Answer 1

• Recurrent episodes of upper airway obstruction leading to apnoea during sleep

Question 2

Symptoms of obstructive sleep apnea syndrome

Answer 2

• Usually associated with heavy snoring
• Typically unrefreshing sleep
• Daytime somnolence /sleepiness
• Poor daytime concentration
• Waking with a transient choking sensation
• Lethargy or tiredness
• Headache on waking
• Nocturnal polyuria
• Reduced libido

Question 3

Why is OSAS important?

Answer 3

• Impaired quality of life
• Marital dysharmony
• Increased risk of RTA’s
• Associated with hypertension, increased risk of stroke and probably increased risk of heart disease.

Question 4

How is OSAS diagnosed?

Answer 4

• Clinical history and examination
• Epworth Questionnaire
• Overnight sleep study
  
  • pulse oximetry
  • limited sleep studies
  • full polysomnography

Question 5

Treatment for OSAS

Answer 5

• 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
• Positional therapy devices

Question 6

Narcolepsy

Answer 6

chronic neurological disorder that affects the brain’s ability to control sleep-wake cycles

Question 7

Clinical features of narcolepsy

Answer 7

• Cataplexy
• Excessive daytime somnolence
• Hypnagogic / hynopompic hallucinations
• Sleep paralysis

Question 8

Investigations for narcolepsy

Answer 8

• PSG
• MSLT (>1 SOREM and mean sleep latency <8 min).
• Low CSF orexin

Question 9

Treatment for narcolepsy

Answer 9

• Modafinil
• Dexamphetamine
• Venlafaxine (for cataplexy)
• Sodium Oxybate (Xyrem)

Question 10

Aetiology of Chronic Ventilatory Failure

Answer 10

• airway disease
• chest wall abnormalities
• respiratory muscle weakness
• central hypoventilation

Question 11

Typical symptoms of chronic ventilatory failure

Answer 11

• Breathlessness
• Orthopnoea
• Ankle swelling
• Morning headache
• Recurrent chest infections
• Disturbed sleep

Question 12

Examination findings of CVF

Answer 12

• Reflects underlying disease
• Particularly look for paradoxical abdominal wall motion in suspected neuromuscular disease
• Ankle oedema (hypoxic cor pulmonale)

Question 13

Investigation for neuromuscular disease

Answer 13

• Lung function
  
  • Lying and standing VC
  • Mouth pressures / SNIP
• Assessment of Hypoventilation
  
  • Early morning ABG
  • Overnight oximetry
  • transcutaneous CO2 monitoring

Question 14

Treatment for neuromuscular disease

Answer 14

• Treat underlying condition e.g. weight loss
• Domicillary Non Invasive Ventilation (NIV)
• Oxygen therapy
  
  • beware that some patients may be dependent on hypoxic drive
• Tracheostomy ventilation

Question 15

Non-invasive ventilation in neuromuscular disease

Answer 15

• Supportive treatment, not curative
• Primarily for symptoms but may also improve prognosis (DMD, some MND)
• Patients may become dependent
• Can be withdrawn at the end of life