Obstructive Sleep Apnoea Flashcards
Define obstructive sleep apnoea
Intermittent obstruction of the upper airway during sleep due to loss of oropharyngeal muscle tone.
Epsidoes of apnoea (breathing temporarily stops) or hypopnoeic episodes (decreased airflow during breathing)
Results in fragmented sleep and excessive daytime sleepiness
What is the relevant epidemiology of obstructive sleep apnoea?
85% of cases are undiagnosed
Increasing with rates of obesity and elderly population
Twice as common in males
Peak incidence in 50-60yrs
What are the main predisposing factors for obstructive sleep apnoea?
Obesity - mechanical load on resp system
Age - change in muscle function/structure, fat distribution around the neck
Male - fat distribution, anatomy of the airway
Menopause - oestrogen and progesterone protective against airway collapse
Family history -
Anatomical - craniofacial, adenotonsillar hypertrophy
Alcohol and sedatives - reduce muscle tone
Medical conditions - hypothyroidism, acromgal, POCs
What is the relevant pathological process underpinning obstructive sleep apnoea?
During sleep reduced muscle tone and negative pressure generated by inspiration leads to airway collapse.
Causes reduction (hypopnoea) or cessation (apnoea) of airflow despite ongoing respiratory efforts
Results in micro-awakenings and fragmented sleep
Thses cycles of hypoxia, reoxygenatoin and sleep fragmentation activates the SANS, oxidative stress and systemic inflammation -> long term complications such as HTN, cardiovascular disease and metabolic disorders.
What are the key clinical features of obstructive sleep apnoea?
Daytime somnolence
Compensated resp acidosis
Hypertension
Morning headaches
Difficulty concentrating
Behavioural problems and hyperactivity in children.
Partner complaines of excessive snoring and apnoea.
What scales can be used to formally assess sleepiness?
Epworth Sleepiness Scale - by patient or partner, chance of sleep in certain scenarios e.g passenger in a car
Multiple Sleep Latency Test - time to fall asleep in dark room
How is obstructive sleep apnoea diagnosed?
Sleep studies (polysomnography) = monitoring pulse oximetry< ECG, resp airflow, thoraco-abdominal movement, snoring.
What is the management of obstructive sleep apnoea?
Weight loss
CPAP - first line if moderate or severe
Intra-oral devices - if CPAP not tolerated or mild
DVLA informed if causing excessive daytime sleepiness
What are some common differential diagnosis for obstructive sleep apnoea?
Insomnia - difficulty falling/staying asleep
Sleep distubrance - shift work
Restless leg syndrome -
Narcolepsy - sudden attacks of sleep, excessive dreaming
Hypothyroidism
Depression
Medication - SSRIs, benzo, antiepileptic
GERD - nocturnal choking and gaspin, can disturb sleep
What are some complications of obstructive sleep apnoea?
Road traffic collisions
Accidents at home or work
Deterioration in mental health - irritability and depression
Cardiovascular and metabolic - stroke, CAD, HTN, CHF, T2DM
