"Narcolepsy is a sleep disorder characterized by constant sleepiness and other features known as cataplexy (sudden loss of muscle tone due to laughter or excitement),sleep paralysis (feeling paralyzed before falling asleep or on waking), and hallucinations around the time of falling asleep and waking-up."
Slide 1: Epilepsy or Narcolepsy? AskTheNeurologist.Com Author Anon
Slide 2: History 16 year old woman suffering from sleep deprivation on a holiday 4 days into trip Excessively sleepy in day Began falling asleep inappropriately On morning of admission, noticed she had bitten tongue to point of bleeding During day, frequent sleep-attacks AskTheNeurologist.Com
Slide 3: Sleep attacks Sometimes felt tired beforehand Occurred on - talking - walking (fell) Absence of Abnormal movements Tongue biting during LOC Incontinence AskTheNeurologist.Com
Slide 4: Past History Mild asthma Tongue biting since childhood Hypnogogic ? intentional Denies Seizures Cataplexy ( fell, but only after LOC) Sleep paralysis Hypnogogic hallucinations AskTheNeurologist.Com
Slide 5: Examination Signs of tongue-biting on side of tongue Orientated Drowsy Repeatedly falling asleep Neurological examination unremarkable AskTheNeurologist.Com
Slide 6: Investigations Blood : - normal ( CBC, Bioch, ESR) Toxic screen negative EEG when drowsy / asleep Synchronous high amplitude activity AskTheNeurologist.Com
Slide 7: Background 26/8 AskTheNeurologist.Com
Slide 8: Drowsy 26/8 AskTheNeurologist.Com
Slide 9: Impression following EEG Episodes of loss of consciousness and falling Signs of tongue biting Rhythmic high amplitude activity when drowsy Hospitalised and anti-epilaptic medication commenced AskTheNeurologist.Com
Slide 10: Course Received diazepam drip and carbamazepine Slept well in hospital Episodes stopped EEG reviewed again AskTheNeurologist.Com
Slide 11: Concept of V-waves Occur at sleep onset from 5 months of age Maximal at 4-5 years May be present at all ages More pronounced during childhood Synchronous sharply contoured waves Negative phase reversal in midline AskTheNeurologist.Com
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Slide 13: EEG tip Be suspicious that any epileptic activity during sleep, with phase reversal in the midline is normal. The coronal montage is especially important during a sleep study, as phase reversal at Cz is sometime the only clue that sharp activity is normal AskTheNeurologist.Com
Slide 20: For Against Narcolepsy Age of onset No other features EDS Sleep attacks Sleep deprivation History of sleep deprivation Too severe Recurrence following discharge with adequate sleep Epilepsy ? Tongue biting Tiredness before LOC ? Response to anti- Episodes of LOC coincide epileptic medications with v-waves and no other epileptic activity A focus near Cz would be associated with focal seizures of leg AskTheNeurologist.Com
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Slide 22: Excessive daytime sleepiness / hypersomnia unintentional naps Onset in teens / early twenties Sleepiness worst during inactivity Improvement following nap May complain of Inattention /memory disturbance Diplopia Automatic behaviour AskTheNeurologist.Com
Slide 23: Aspects of REM sleep intrude into wakefulness Cataplexy Hypnagogic hallucinations Sleep paralysis AskTheNeurologist.Com
Slide 24: Hypnagogic hallucinations Dream-like episodes Often frightening Occur during drowsiness or onset of sleep Usually visual May be Tactile Auditory Vestibular (sense of falling) AskTheNeurologist.Com
Slide 25: Sleep paralysis Profound weakness May be at onset of sleep or on waking May cause fear / feeling of choking Is intrusion of ( protective) REM sleep paralysis into wakefulness Sleep paralysis and hypnagogic hallucinations may occur following sleep deprivation AskTheNeurologist.Com
Slide 26: Cataplexy Sudden muscle weakness, no LOC Triggered by intense emotion Laughter Anger Similar concept to sleep paralysis Present in 60% of narcolpetics Usually occurs 3-5 years following onset of sleepiness AskTheNeurologist.Com
Slide 28: Polysomnography Evaluates sleep quality Excludes other causes of sleepiness: Obstructive Sleep apnea Periodic leg movements REM sleep behaviour disorder AskTheNeurologist.Com
Slide 29: MSLT Performed day after polysomnography Given opportunity to nap 2 hours Narcoleptics fall asleep within 5 minutes Normal = 10-15 minutes Naps often contain REMs (SOREMs) AskTheNeurologist.Com
Slide 30: Diagnosing Narcolepsy Chronic sleepiness AND Either: - Cataplexy OR: - > 2 SOREMs in MSLT d Idiopathic hypersomnia Chronic sleepiness without either of other criteria AskTheNeurologist.Com
Slide 32: Genetics of narcolepsy 1 / 2000 Usually sporadic HLA DR2, DQ1 ( DQB1*0602) AskTheNeurologist.Com
Slide 33: Role of orexin ( hypocretin) Orexin-containing neurons found in posterior and lateral hypothalamus Innervate aminergic annd cholinergic neurons that provoke wakefulness AskTheNeurologist.Com
Slide 34: Brown = Tyr OHlase staining of Locus Coerulius neuron Black = terminals immunoreactive for orexin AskTheNeurologist.Com
Slide 35: Evidence for orexin hypothesis Intraventricular injection of orexin causes wakefulness Knockout mice ( orexin or receptor) have disease resembling narcolepsy Doberman dogs with orexin receptor mutations have narcolepsy and cataplexy Absence of CSF orexin correlates well with cataplexy AskTheNeurologist.Com
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Slide 37: Cataplexy and Sleep paralysis:- Intraventricular injection of orexin causes wakefulness Knockout mice ( orexin or receptor) have disease resembling narcolepsy Doberman dogs with orexin receptor mutations have narcolepsy and cataplexy Absence of CSF orexin correlates well with cataplexy AskTheNeurologist.Com
Slide 38: Sleep paralysis = opposite problem i.e. in RBD lose the protective paralysis which is inappropriately active in sleep paralysis and cataplexy. AskTheNeurologist.Com