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Toronto Notes 2019 Sleep Disorders Disturbances of Alertness and Sleep
Coma
• seeNeurosurgery,NS35
Insomnia
• difficultyinitiatingormaintainingsleep,orwakingupearlierthandesired(leadingtosleepthatis chronically non-restorative/poor quality) despite adequate opportunity and circumstances for sleep
• types
■ sleep state misperception, psychophysiologic insomnia (learned sleep-preventing associations
– i.e. clock watching), fatal familial insomnia (rare prion protein mutation causing autonomic
dysfunction), idiopathic (lifelong difficulty) ■ secondarycauses
◆ psychiatric disorders (80% of psychiatric patients): depression and anxiety (see Psychiatry, PS10, PS13)
◆ neurologic disorders: neurodegenerative disease, epilepsy, neuromuscular disorders, many others
◆ sleep disorders: restless legs syndrome (sleep initiation difficulties), sleep apnea (sleep
maintenance difficulties)
◆ medical conditions: pregnancy, cardiorespiratory (COPD/heart failure), GERD, pain (arthritis,
fibromyalgia, cancer)
◆ drugs/toxins: caffeine, alcohol, stimulants, antidepressants, glucocorticoids, sedative withdrawal
• treatment
■ sleep log, sleep hygiene, stimulus control, sleep restriction, relaxation response, CBT
Sleep Apnea
• disorderofbreathinginsleepassociatedwithsleepdisruptionandconsequentexcessivesomnolence (or drowsiness)
• epidemiology
■ >2-4% of the population
■ correlated with obesity
■ significant morbidity: HTN, stroke, heart failure, sleepiness, mortality (accidents)
• types
■ obstructive sleep apnea
■ central sleep apnea: no effort to breath >10 s
■ mixed apnea: starts as central, but eventually becomes obstructive
• etiologyofcentralapnea:heartfailure,opiates,brainstempathology,myotonicdystrophy
• etiologyofobstructiveapnea:collapseofairwayduetolowmuscletoneindeepandREMsleep
• diagnosis:apneahypopneaindex(AHI)orrespiratorydisturbanceindex(RDI)shouldbe
<5 in the normal state
• treatment:conservativemeasures,dentaldevices,CPAP(common),surgery(rare),ensuredrivingsafety
Restless Leg Syndrome (RLS) and Periodic Limb Movement in Sleep (PLMS)
• urgetomoveaccompaniedbyuncomfortablesensationsthatbeginorworsenwithrest,arepartiallyor totally relieved with movement, and are worse in evening/night; these features cannot be accounted for by another medical/behavioural condition
• RLSreferstosensation
• PLMSreferstothemanifestation
• epidemiology:10%NorthAmericans,90%ofRLShavePLMS,50%ofpatientswithPLMShaveRLS
• etiology:central(spasticity),peripheralnervoussystem(radiculopathy,neuropathy),pregnancy,iron
deficiency, alcohol use
• treatment
■ underlying contributors (iron and B12 supplementation), dopaminergic agonists (first line), clonazepam (causes tachyphylaxis), opioids (only exceptional circumstances)
■ NOT recommended: levodopa/carbidopa (Sinemet®), causes augmentation
Narcolepsy
• definition/clinicalfeatures:excessivedaytimesleepiness(allnarcolepsy),cataplexy=lossofmuscle tone with emotional stimuli (pathognomonic), sleep paralysis (unable to move upon wakening), hypnagogic hallucinations (vivid dreams or hallucinations at sleep onset)
• epidemiology:prevalence1:2,000,onsetinadolescence/earlyadulthood;life-longdisorder
• etiology:presumedautoimmuneattackonorexin/hypocretinsystem,postheadinjury,MS,
hypothalamic tumours; rarely familial
• diagnosis:basedonclinicalhistory+multiplesleeplatencytestfindingsofshortsleeplatency<8min
and REM within 15 min of sleep onset on 2/4 naps
• treatment
■ sleep hygiene and scheduled brief naps, restricted driving
■ alerting agents: modafinil (non-amphetamine stimulant), stimulant (i.e. methylphenidate) ■ anticataplectic: TCAs, SSRIs, sodium oxybate
Neurology N47
Drug Effects on Wakefulness and Sleep
• Antihistamines associated with increased sleepiness
• Stimulants increase arousal
• Caffeine (an adenosine antagonist)
increases wakefulness
• Benzodiazepines reduce slow wave sleep
• Antidepressants (TCA/MAOI/SSRI) reduce
REM, prolong REM latency
• Alcohol may hasten sleep onset but associated with increased arousals
Avoid sleep medications (especially in elderly patients) due to increased risk of falls, pseudodepression, and memory loss