sleep apnoea and neuromuscular respiratory failure - adults Flashcards
what are the symptoms of obstructive sleep apnoea syndrome?
-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
what is the pathophysiology of OSAS?
- muscle relaxation
- narrow pharynx
- obesity
what does muscle relaxation, narrow pharynx and obesity lead to in OSAS?
repeated closure of upper airway which will lead to apnoeas and hypopneas
what is hypopnoea?
partial apnoeas, shallow breathing and low respiratory rate
what do apnoeas and hypopneas lead to during sleep?
microarousals
what conditions are at increased risk in patients with OSAS?
hypertension, strokes and probably heart disease
should sufferers of untreated OSAS drive?
no as there is an increases risk if RTAs in these people
how is OSAS diagnosed?
- clinical history and examination
- Epworth questionnaire
- overnight sleep study
give some examples of over night sleep studies
pulse oximetry
limited sleep studies
full polysomnography
what is the desaturation rate in a normal person?
0-5 per hour
what is the desaturation rate in someone with mild OSAS?
5-15 per hour
what is the desaturation rate in someone with moderate OSAS?
15-30 per hour
what is the desaturation rate in someone with severe sleep apnoea?
> 30 per hour
what are the treatment options for OSAS?
- treating exacerbating factors
- CPAP
- mandibular repositioning splint
what are the exacerbating factors of OSAS?
obesity
alcohol
some endocrine conditions, eg. hypothyroidism
can narcolepsy be familial?
yes
what are the clinical features of narcolepsy?
cataplexy
excessive daytime somnolence
hypnagogic hallucinations
sleep paralysis
what are the treatments for narcolepsy?
modafinil
clomipramine
sodium oxybate
what does modafinl treat?
sleepiness
what does clomipramine treat?
cataplexy
what does sodium oxybate treat?
cataplexy
what are the characteristics of chronic ventilatory failure?
elevated pCO2 >6.0 kPa
pO2 <8kPA
normal blood pH
elevated bicarbonate
what airway diseases can cause chronic ventilatory failure?
COPD
bronchiectasis
OSAS
what chest wall abnormalities can cause chronic ventilatory failure?
kyphoscoliosis
what conditions causing respiratory muscle weakness can cause chronic ventilatory failure?
motor neurone disease
muscular dystrophy
which conditions can cause central hypoventilation which can cause chronic ventilatory failure?
obesity hypoventilation syndrome
central hypoventilation syndrome
what are the symptoms of chronic respiratory failure?
breathlessness orthopnoea ankle swelling morning headache recurrent chest infections disturbed sleep
what are the signs of chronic respiratory failure?
- paradoxal abdominal wall motion inome suspected neuromuscular disease
- ankle oedema (from hypoxic cor pulminale)
what are the investigations for chronic respiratory syndrome caused by neuromuscular syndrome?
lung function: lying and standing VC, mouth pressures
assessment of hypoventilation: early morning ABG, overnight oximetry, transcutaneous CO2 monitoring
what is the treatment for chronic respiratory failure?
domicillary non invasive ventilation
oxygen therapy
