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Narcolepsy"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."
The following case presentation and discussion deals with a young girl originally suspected as suffering from epilepsy:-
"This video shows a narcoleptic poodle although most of the attacks actually are of cataplexy rather than falling asleep."
Human video description of narcolepsy and cataplexy
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Slideshow transcript:-
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 Slide 12: AskTheNeurologist.Com 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 14: AskTheNeurologist.Com Slide 15: “ Drowsy” 26/8 AskTheNeurologist.Com Slide 16: Coronal 26/8 drowsy AskTheNeurologist.Com Slide 17: Coronal 26/8 low amplitude AskTheNeurologist.Com Slide 18: Follow-up EEG 28/8 AskTheNeurologist.Com Slide 19: DD 1) Narcolepsy / hypersomnia 2) Sleep deprivation 3) Epilepsy 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 Slide 21: AskTheNeurologist.Com 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 27: Lab. Findings • Polysomnography • Multiple sleep latency test ( MSLT) 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 31: Secondary causes of narcolepsy • Posterior hypothalamic lesions – Tumour – Stroke / AVM – Sarcoidosis – Paraneoplastic ( anti-Ma) – MS 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 OH’lase 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 Slide 36: AskTheNeurologist.Com 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. 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