Sleep Disorders Flashcards
Discuss the purposes of sleep
Regeneration of physiological system - NREM sleep for physical regeneration - REM sleep for cognitive regeneration Energy Conservation - Immune function regulation Stimulation of CNS development in children Memory consolidation Protective mechanism
Discuss the stages of sleep
- newborn is 50/50, in child 80% NREM and 20% REM and as get older REM increases
Non-Rapid Eye Movement Sleep - breathing regular and heart rate increases
- low muscle tone
- slow infrequent eye movements
- N1: lightest stage of sleep with hypnic jerks and sleep starts
- N2: sleep spindles and K complexes
- N3: deep sleep wave on EEG, deepest most physically restorative sleep with difficulty awakening
Rapid Eye Movement Sleep - alpha wave like when awake
- rapid eye movement (fish mouth on electro-oculogram)
- no muscle tone
- last 90 min/cycle
- dream recall
- breathing is irregular and heart rate fluctuates
List the locations of the arousal system
Reticular formation mediates wakefulness
- nor-adrenergic originating in locus coeruleus
- serotonin originating in raphe nucleus
- dopaminergic originating in ventral tegmental area and substantia nigra
- histamine from tuberomammillary system
- acetylcholine from basal forebrain and from laterodorsal and pendunculopontine tegmental nuclei in brainstem
Location of NREM Sleep system
- ventrolateral pre-optic area has diffuse projections of GABA to centre of arousal system, resulting in inhibition
Location of orexin system
- orexin is hypocretin which stabilize wakefulness in wake and stabilize sleep in sleep state
- originate in hypothalamus and project to other areas
Discuss the circadian rhythm synchronization to time of day
During day
- light detected by retina input to supra-chiasm nucleus -> stimulate sympathetic system to turn off melatonin secretion from pineal gland
During Night
- lack of light result in inactivation of supra-chiasm nucleus -> which inhibits sympathetic system on pineal gland -> secrete melatonin which feeds back to supra-chiasm to synchronize circadian rhythm
Discuss the features of a Overnight polysomnogram
Electroencephalogram: measure brain activity
Electro-oculogram: measure eye movement
Electromyogram: measure muscle tone on submental and leg
Electrocardiogram: heart rate
Pressure transducer and CFLOW at nose and mouth with respiratory effort band on ribcage and abdomen to detect apnea
Finger oximetry: assess desaturations
Microphone: snoring
Digital recording: assess behaviour
Discuss the features and indications for multiple sleep latency test
Indication - narcolepsy Procedure - patient given 4-5 20 minute nap opportunities set two hours apart Measurement - normal sleep latency >12 minutes - pathological <6 minutes
List the causes of acute insomnia
- last less than 1 month and is self limited Stressful personal event Impending stressor Acute illness Management - drug for <10 days
List the criteria for insomnia
Predominant complaint of dissatisfaction with sleep quantity, quality with >=1
- difficulty initiating sleep (anxiety)
- difficulty maintaining sleep
- early morning awakenings with inability to return to sleep (depression)
Cause distress or impair functioning
>=3 nights/week for >=3 months
Difficulty despite adequate opportunity for sleep
Discuss the management for insomnia
Identify and treat medical or surgical problems
- substance abuse then direct treatment to withdrawal
Elicit detailed insomnia history
- caffeine
- sleep hygiene
- naps
Psychiatric diagnosis screening
- depression, anxiety, substance abuse
Refer to sleep clinic
- symptoms of sleep apnea
- sypmtoms of restless leg syndrome
- REM behaviour disorder or nocturnal epilepsy
- chronic insomnia without obvious cause
- medications: Trazadone or Mirtazepine for chronic
Discuss the pathophysiology of obstructive sleep apnea
Upper airway narrowed and obstructed due to
- tongue falls back
- relaxation of oropharyngeal muscles
- redundant tissue in obesity
Lead to obstruction of upper airwary preventing airflow despite respiratory effort -> oxygen desaturations and hypercapnia which trigger increased effort -> disrupt sleep -> disruption lead to increased ADH causing nocturia, increased sympathetic tone leading to hypertension
List the epidemiology, pathophysiology, presentation and management of sleep walking
Epidemiology - more common in children - positive family history Pathophysiology - arousal in slow wave sleep, N3, resulting in elaborate motor activity but cortical state of sleep Presentation - perform elaborate motor activity with heightened pain threshold - no recall or episode - aggrevated by sleep deprivation, stress, alcohol Management - do not awaken - secure environment
List the epidemiology, pathophysiology, presentation and management of sleep terrors
Epidemiology - children Pathophysiology - arousal from slow wave sleep, N3, resulting in scream in state of sleep Presentation - scream while being asleep then back to peaceful sleep - no recall Management - outgrow by late teen
List the epidemiology, pathophysiology, presentation and management of REM Behaviour Disorder
Epidemiology - more common in older males, 50-60 - associated with synucleinopathies (Parkinson's, Lewy body) Pathophysiology - arousal in REM sleep resulting in regaining muscle tone - move and act out dream Presentation - violent behaviour while asleep hurting bed partner - opposite of waking personality - recall dream Investigation - full EEG during overnight to rule out seizure - MRI to rule out lesison Management - secure environment to prevent injury - benzodiazepine (clonazepam) 1st line
List the epidemiology, pathophysiology, presentation and management of narcolepsy with cataplexy
Epidemiology
- young adulthood
Pathophysiology
- genetic with abnormal hypocretin receptor
- demyelinating disease, tumour
- irregular sleep-wake pattern
- lack of orexin lead to intrusion of wakefulness into sleep and sleep into wakefulness
- abnormality of REM sleep with cataplexy
Presentation
- excessive daytime sleepiness (fall asleep without warning or unusual situations)
- cataplexy: sudden onset of full or partial flaccid muscle weakness or paralysis except for eye or diaphragm triggered by strong emotion lasting <2 minutes
- hypnagogic: hallucination going to sleep
- hypnapompic: hallucination upon awakening
- Sleep paralysis: awake but can only move eyes
- Disturbed nocturnal sleep
Investigations
- CSF hypocretin levels <110
- overnight somnography (short REM latency period <15min with a low of awakenings)
- Multiple sleep latency test
- require adequate total sleep time before study and no psychotropic medication for 2 weeks
- narcolepsy with sleep onset <8 minutes and >=2 sleep onset REM period
Treatment
- CNS stimulant (methylphenidate)
- REM suppressants for cataplexy (SSRI, TCA)
- Benzodiazepines for sleepiness and cataplexy given at night and 3 hours later
List the epidemiology, pathophysiology, presentation and management of restless leg syndrome
Epidemiology
- affect 5-10% with more females
- 40-50
Pathophysiology
- dopamine deficiency and low iron in CNS cause primary
- secondary due to another disorder (end stage renal disease, peripheral neuropathy, substance, anti-dopaminergic medication)
Presentation (URGE)
- urge to move limbs while awake in evening
- rest worsens symptoms
- getting up or moving improves
- evening worsening or night-time appearence
- >=3x/week for >=3 months
- distress and impaire function
Investigation
- iron, ferritin
Treatment
- Dopamine agonist (mild: <=3/week then levodopa as needed; severe >3/week then mirapex 1-2hr before symptom onset
- Pregabalin, Gabapentin
- benzodiazepine or opioids
List the epidemiology, pathophysiology, presentation and management of periodic limb movement in sleep and periodic limb movement disorder
Pathophysiology
- dopamine deficiency
Presentation
- In sleep have brief repetitive leg movement <5sec that occur during sleep at 20-40sec intervals (big toe extension with dorsiflexion)
- patient unaware but disturb sleep pattern and partner
- occur in first 1/3 of night
- in disorder movement causes significant sleep disturbance
Diagnosis
- >=4 consecutive regular limb movement on EMG associated with disruption of sleep on EEG (arousal)
Treatment
- same as restless leg syndrome
