Sleep Disorders Flashcards
List 4 broad causes of daytime sleepiness, from most common to least common
Lifestyle (not getting enough sleep!) Drugs/alcohol (e.g. benzodiazepenes, anti-depressants) Sleep breathing disorders RLS/periodic limb movement disorder Neurological disease Insomnia Narcolepsy Idiopathic hypersomnia Circadian disorders Psychiatric disorders Post-viral
Lifestyle (not getting enough sleep)
Conditions disrupting sleep:
Drugs/alcohol
Sleep-related conditions
Distinguishing between sleepiness vs tiredness/lethargy
Sleepiness: narrower differential diagnosis
Tiredness/lethargy: broader differential diagnosis (chronic disease)
How can sleepiness be distinguished from tiredness/lethargy?
Epworth sleepiness scale: patient is asked what their chance of dozing would be in a number of contexts (normal 15 confers 2x risk of MVA; use in fitness to drive assessments)
Summarise the respiratory control changes at sleep onset
Loss of wakefulness drive to breathe and behavioural influences
Down-regulation of respiratory reflexes, chemosensitivity, and upper airway and respiratory pump muscle tone (thereby increasing upper airway resistance)
What is the major regulator of breathing during sleep?
Chemical control
What are the cardinal symptoms of OSA?
Heavy snoring
Excessive daytime somnolence
Witnessed apnoeas
List some other nocturnal symptoms of OSA
Disrupted/restless/unrefreshed sleep
Nocturnal choking and gasping
Nocturia
Mechanism of OSA
pO2 starts to fall, pCO2 starts to rise
Individual tries to breathe harder but this increases the negative pressure, causes closing of upper airway
Central drive reaches threshold for waking
List some other daytime symptoms of OSA
Headaches (nocturnal/morning) Memory/cognitive/concentration deficit Mood change (depression/irritability) Sexual dysfunction (decreased libido or impotence) Uncontrolled HTN
List 5 cardio-respiratory effects of OSA
HTN Cor pulmonale MI Arrhythmias/sudden death Polycythaemia
List 5 risk factors for OSA
Age Male gender Obesity Alcohol/sedatives Upper airway morphology including nasal obstruction
What are the criteria for diagnosis of OSA?
Apnoea hypopnoea index (AHI) >5 events/hr
5-15 mild, 15-30 moderate, >30 severe (ranges not really useful; better to assess symptoms)
How can OSA be diagnosed?
In laboratory OR at home full polysomnography
Define apnoea
Complete cessation of airflow for ≥10 secs, regardless of O2 desaturation
Define hypopnoea
≥30% reduction in airflow associated ≥3% O2 desaturation or an alpha wave arousal from sleep
What are the 4 options for OSA management?
Conservative treatments
CPAP
Oral appliances
Surgery
List 5 options for conservative treatment of OSA
Weight loss Avoid alcohol, tobacco and sedatives Body position Treat nasal congestion Treat medical disorders
Where might the use of oral appliances be advised?
Snoring
Mild to moderate OSA
Failed CPAP treatment
List some contraindications to oral apliances for management of OSA
Dentures or lack of teeth Periodontal problems TMJ disorder Severe nasal obstruction Severe hypoxia
List some SEs of oral appliances for management of OSA
Excessive salivation
Discomfort in the teeth and jaw
Movement of teeth
TMJ dysfunction
List 3 types of sleep disordered breathing
OSA
Central sleep apnoea
Sleep hypoventilation
Define central sleep apnoea
Apnoeas or hypopnoeas caused by reduction in central respiratory drive
What are the 4 main causes of central sleep apnoea?
Cardiac failure (Cheyne-Stokes respiration; main cause)
High altitude
CNS disorders (e.g. CVA)
Idiopathic
How is central sleep apnoea managed?
Depends on underlying causes (e.g. for Cheynes-Stokes, manage heart failure)
List some causes of hypoventilation
Reduced respiratory centre activity Neuromuscular disease Chest wall deformity Obesity Increased ventilatory requirements
Victorian requirements for driving
AHI >35
ESS >15
55 year old male, 110 kg, taxi driver
Fell asleep at the wheel and was woken by passenger
Long Hx of snoring, sleeps alone
Driving 15 hours per day; says he sleeps on the rank
6 hours per night in bed
Likely Dx?
OSA
Is OSA more common in males or females?
Males
List 5 neuropsychological effects of OSA
Excessive sleepiness Psychological problems Stroke Dementia In children: behavioural problems, poor school performance, ADHD
Describe 4 factors contributing to the pathogenesis of OSA
Anatomically narrow upper airway
Upper airway muscle weakness
Poor respiratory control (with propensity to develop cyclical breathing)
Reduced arousal threshold (leading to cycling)
What are the diagnostic criteria for OSA?
AHI >5 events per hour (events/total sleep time)
How is the severity of OSA graded?
Mild: 5-15
Moderate: 15-30
Severe: >30
How effective is weight loss as a treatment for OSA?
10% weight loss results in a 26% reduction in AHI
Adaptive Servo-Ventilation (ASV)
Uses an algorithm which detects significant reductions or pauses in breathing and intervenes with just enough support to maintain the patient’s breathing at 90% of what had been normal prior to decreased breathing
Algorithm is based off a set rate of breaths per minute that the patient should be taking; when the patient’s breathing dips below these rates, the ASV delivers just enough air pressure to keep the patient breathing regularly
How is Cheyne-Stokes breathing managed?
Treat HF
CPAP
?O2
Adaptive Servo-Ventilation (ASV)
How is idiopathic CSA treated?
?O2
?NIV
Describe the “balance of forces” in respiration
Pro-respiratory: respiratory drive, nerve integrity, muscle integrity, “bellows” structure
Anti-respiratory: upper and lower airway resistance, elastance, gas exchange requirements
22 year old male, difficulty sleeping since early teens, mainly due to sleep onset insomnia
Once asleep sleeps well, but has to get up for work after 4/24
Describes that he “cannot get comfortable” in bed
Non-snorer, thin
Minimal alcohol, no illicit drugs, 1 coffee daily
What aspects of Hx would be consistent with a diagnosis of chronic insomnia?
Subjective dissatisfaction with sleep quality or duration, difficulty falling asleep at bedtime, waking up in the middle of the night or too early in the morning, or non-restorative or poor quality sleep
Associated daytime symptoms and functional impairments
Is chronic insomnia more common in females or males?
Females
What is “primary” insomnia?
A disorder of “hyperarousal”
List 6 changes seen in primary insomnia which may be associated with its pathophysiology
Increased anxiety Increased HPA axis activity Increased HTN Increased ANS activity in sleep Changes in sleep EEG with more faster frequency waves Increased brain glucose uptake in sleep
List 8 disorders which may contribute to the onset of insomnia
OSA Circadian disorders Restless legs Psychiatric disorders Substance abuse Pain Urinary problems Rx
How can insomnia be assessed/monitored?
Sleep diary
Actigraphy
8 treatment strategies for insomnia
Treat comorbid disorders Stimulus control therapy Sleep restriction Relaxation Biofeedback Paradoxical intention Sleep hygiene Short term hypnotics
What pharmacological treatments are used for insomnia?
Benzodiazepines Non-benzodiazepines Antidepressants Valerian Antihistamines
What principles must be considered when deciding whether to manage insomnia pharmacologically?
Hypnotic medications should not be the first choice of treatment
Rx should be used in short term management of idiopathic or psychophysiological insomnia
Rx should be combined with non-pharmacological measures when tapering the dose
List 7 circadian disorders
Delayed sleep phase syndrome Advanced sleep phase syndrome Non-24 hr circadian rhythm Free-running rhythm Jet lag Shift work disorder Seasonal affective disorder
In what % of the population does restless legs syndrome occur?
5-15%
Increases with age
List the 4 International Restless Legs Study Group Criteria
Desire to move the extremities often associated with parasthesias or dysaesthesias
Motor restlessness
Worsening of symptoms at rest with at least partial and temporary relief during activity
Worsening of symptoms in the evening or at night
List 5 secondary causes of restless legs syndrome
Iron deficiency Renal failure Peripheral neuropathy Lumbosacral radiculopathy Pregnancy
How is familial restless legs syndrome inherited?
AD
List 5 consequences of restless legs syndrome
Sleep disturbances Tiredness or fatigue during daytime Reduced emotional well-being/QOL Avoidance of social activities Possibly higher incidence of CVS risk factors/CVS disease
What is periodic limb movement disorder?
Repetitive movements of the limbs (usually legs) that occur during sleep and may be associated with arousal
How is periodic limb movement disorder diagnosed?
PLM index on polysomnography
What is the relationship between RLS and PLM?
80% with RLS have PLM
>50% PLM have RLS
What is narcolepsy?
Disorder of sleep regulation, with an intrusion of some REM sleep into wakefulness and abnormal regulation sleep timing
What is the pathophysiology of narcolepsy?
Deficiency in the neurotransmitter orexin
When is the typical onset of narcolepsy?
Begins in teens and 20s (but can occur after 40)
What is the inheritance pattern of narcolepsy?
AD with incomplete penetrance
Associated with HLA-DQB1*0602
What are the main features of narcolepsy?
Excessive daytime sleepiness
Manifestations related to REM sleep
What are the features of excessive daytime sleepiness seen in narcolepsy?
“Sleep attacks”, ESS>15, refreshed following nap
Abnormally timed REM sleep
Abnormal result on a multiple sleep latency test (MSLT)
What manifestations related to REM sleep may be seen in narcolepsy?
Hypnagogic/hypnopompic hallucinations
Sleep paralysis (complete inability to move for 1-2 minutes after awakening)
Cataplexy
Cataplexy
A medical condition in which strong emotion or laughter causes a person to suffer sudden physical collapse though remaining conscious
What are the criteria for a diagnosis of narcolepsy?
Excessive daytime sleepiness
Cataplexy
MSLT (mean sleep latency
SOREM
Sleep-onset rapid eye movement
How can narcolepsy be treated?
General measures
Pharmacologically
List 5 general measures used to manage narcolepsy
Avoid shifts in sleep schedule Avoid heavy meals and alcohol intake Regular timing of nocturnal sleep Strategically timed naps, if possible (e.g. 15 mins at lunchtime, 15 mins at 5.30pm) Career counselling
List 2 types of pharmacological treatments used to manage narcolepsy
Stimulants (e.g. modafinil, amphetamines)
REM-suppressing drugs (e.g. SSRIs, tricyclics)
2 examples of amphetamines used in the treatment of narcolepsy
Dexamphetamine
Methylphenidate
2 examples of SSRIs used in the treatment of narcolepsy
Fluoxetine
Venlafaxine
List 5 diagnostic criteria for idiopathic hypersomnia
DIAGNOSIS OF EXCLUSION:
Complaint of EDS and prolonged, often unrefreshing naps
Difficulty waking up in the morning or after a nap (sleep drunkenness)
Insidious onset prior to age 30
Duration of at least 6 months
Exclusion of conditions that may cause the same symptoms on polysomnogram and MSLT (i.e. latencies between 5-10 mins, no SOREMs)
Describe the pathogenesis of idiopathic hypersomnia
Unknown
How is idiopathic hypersomnia treated?
Stimulants
1/4 spontaneously improve
What is a parasomnia?
Undesirable behaviour or experiences in sleep or in transition to or from sleep
List 3 disorders of arousal (from non-REM sleep)
Confusional arousals
Sleepwalking
Sleep terrors
List 3 parasomnias usually associated with REM sleep
REM sleep behaviour disorder
Recurrent isolated sleep paralysis
Nightmare disorder
List 6 other types of parasomnias
Sleep-related dissociative disorder Sleep enuresis Sleep-related groaning Exploding head syndrome Sleep-related hallucinations Sleep-related eating disorder
When do disorders of arousal typically occur?
When arising from slow wave sleep (is a mixed state between sleep and wakefulness)
Usuaully occurs in the first 1/3 of night
What factors may exacerbate disorders of arousal?
Factors which deepen sleep
Factors which disturb sleep
How do disorders of arousal present?
Confusion when woken and mentation slow
Complex activity possible
At what stage of life are disorders of arousal more common?
In childhood
Do disorders of arousal have a familial component?
Yes
What is the main DDx for a disorder of arousal?
Seizure disorder
List 8 points of management for disorders of arousal
Reassurance Alter sleep environment for safety Avoidance of precipitants Treat stress Sleep extension Scheduled wakenings Clonazepam/tricyclics L-tryptophan for sleep terrors
Clonazepam
Benzodiazepine (also used for seizures)
What is the rationale behind the use of L-tryptophan for sleep terrors?
It is converted into serotonin
List 3 types of REM parasomnias
REM behaviour disorder
Frequent nightmares
Isolated sleep paralysis
Who is the typical demographic affected in REM behaviour disorder?
Elderly men predominantly (0.5% prevalence)
Association with neurodegenerative disorders
What is REM behaviour disorder characterised by?
Dream enactment behaviour (often violent)
Failure of REM atonia/locomotor quiescence
What different forms of REM behaviour disorder are there?
Idiopathic/secondary forms
What may precipitate the acute form of REM behaviour disorder?
Injury
CVA
SSRI
How is REM behaviour disorder managed?
Treat associated conditions
Stop causative medications
Consider use of clonazepam (80-90% respond), melatonin
