S2 - Obstructive sleep apnoea Flashcards
(34 cards)
Describe sleep cycles
normally 5 sleep cycles every night
- First REM occurs 90min after falling asleep then every 90min, gets longer later 2. Then light sleep, lasts up to 7min, prone to twitches and hypnagogic jerks (stage 1) 3. Then deep sleep (what makes you feel well rested) REM cycles get longer and deepness of sleep gets less through the night (stage 2-4)
- how much sleep is needed varies between individuals
Prevalence of OSA, how does age affect it
5% of population, incidence goes up with age (12% in over 45s), very rare in children
What are the sleep disorders: insomnia, parasomnia, sleep related breathing and movement disorders, narcolepsy and circadian rhythm sleep disorders
Insomnia: difficulty falling and/or staying asleep
Parasomnia: sleep walking, talking, abnormal movments, night terrors
Sleep related breathing disorders: snoring, CSA, OSA
Sleep related movement disorders: restless leg syndrome, nocturnal bruxism
Narcolepsy: overwhelming daytime drowsiness leading to sleeping (often associated w other sleep disorders)
Circadian rhythm sleep disorders: jet lag, shift work
Reasons for indirect financial costs to govt associated with sleep disorders and conditions attributed to them (3)
- lost productivity
- welfare benefits
- car accidents
Which other health conditions are you at increased odds of with sleep apnoea (men)
- heart failure
- schizoprenia
- heart attack
- depression/anxiety
- PTSD
- angina
- diabetes
How common is snoring? What causes it (adults vs children).
40% of adults (M>F)
results from vibration of loose soft tissues in airway as air passes over them
snoring in children - often due to enlarged tonsils or adenoids
T/F Snoring = sleep apnoea
F, not necessarily
Types of sleep apnoea
- CSA (central) = airflow ceases due to temporary lack of inspiration (CNS issue), causes include:
- Polymyelitis
- Spinal cord injury
- Encephalitis
- Brain tumours in children
(i. e. diseases affecting CNS)
2. OSA = airflow stops due to a physical obstruction
3. Complex (combination)
Apnoea vs Hypopnea
apnoea - total cessation of airflow for atleast 10s
hypopnea - reduced airflow for atleast 10s accompanied by arousal or drop in O2 sat
How is severity of sleep apnoea calculated?
apnoea-hypopnea index (AHI)
AHI = apnoea episodes + hypopnea episodes / sleep hours
more severe in children - so threshold lower
Pathophysiology of sleep apnoea
obstructive episode → increased breathing effort → muscles work harder → reduced O2 and increased CO2 in blood (signals brain) → wakes up → hyperventilation → reduced CO2 and increased O2 → return to sleep → upper airway occludes → so on…
Why might OSA cause someone to wake up tired?
takes about 25mins to get into deep stage of sleep (what makes you feel most rested) → if many apnotic episodes, you never rly get down to this level and keep going up to the lighter stages of sleep
Which part of the sleep cycle does OSA happen?
depends, some ppl its throughout, some ppl only in REM sleep and some in deep sleep
children more likely to have in REM sleep
**Symptoms of sleep apnoea
- poor concentration
- low mood
- restless sleep
- heartburn (decrease in inter-thoracic pressure causes liquid to come up oesophagus)
- waking up w headache or dizzy
- night sweats
- insomnia
- weight gain
- excessive daytime fatigue
- forgetfulness
- irritability
*Risk factors for sleep apnoea in adults (modifiable and non-modifiable)
- obesity (biggest)
- smoking or alcohol (esp before bedtime, relaxes airway muscles, more likely to occlude)
- upper airway collapsibility
- male sex
- older age
- hereditary
*Dental risk factors for sleep apnoea
- high narrow palate
- narrow dental arches
- increased anterior face height (long)
- increased overjet
- retrognathia
- large tongue
- tonsilar hypertrophy
Risk factors for sleep apnoea in children. Why do they differ from adults?
enlarged tonsils and/or adenoids are most common risk factor in children
(lymphoid tissues enlarged in childhood, peaks 9-12, goes down in teens)
unlike adults, obesity is not the main risk factor but 50% of obese children present with OSA vs 1-4% of general paediatric population
but some kids underweight; failure to thrive
Differences between adults and children OSA summary
AHI > 5 defines OSA in adults wheres >1 for kids
Management of adults with OSA (5)
- weight management
- smoking, alcohol cessation (in evenings)
- sleeping position (not supine)
- CPAP-Continuous Positive Airway Pressure - forces air down and opens obstruction - only 50% compliance rate, dries airway (if everything else fails)
What to tell patients to use as guide when losing weight for OSA
BMI (body mass index)
weight in kg/height^2
(kg/m^2)
Management of children with OSA. What is the biggest concern.
- Referral to ENT for adenotonsillectomy (to check if needed) - mainstay
- pharmacological agents to reduce lymphoid tissue (dont rly do anything so might be better to just remove)
- weight loss if obese
- CPAP → maxillary retrusion, class III (backward pressure on nose & mx, failure to grow fwd)
failure to thrive is biggest concern (physically, intellectually, mentally, emotionally)
Implications of OSA for dentist/ortho
- under diagnosed and under reported
- dentists are in unique position as they see pt’s regularly
- dentists can also have role in mgt through provision of md advancement appliances (for pts who cant tolerate CPAP → should be done under GUIDANCE and mgt of specialist sleep physician
How to screen adults for OSA
- Mallampati score: class 1)complete visualisation of soft palate, 2) complete uvula 3) base of uvula 4) soft palate not visible at all → 3 & 4 more risk
- Scalloped tongue - tongue presses during teeth in sleep, 70% diagnostic for OSA, also sign of nocturnal bruxism (or both)
- STOP-BANG Questionnaire: (>3 suggestive of OSA, higher score = higher risk)
*if pt has bruxism, enquire about OSA
STOP-BANG Questionnaire
- snoring
- tiredness
- observed apnoeas
- hypertension
- BMI>35kg/m2
- age>50
- neck circumference>40cm
- gender - male
score >3 suggestive of OSA, higher score = higher risk
