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What is Narcolepsy?

What is Narcolepsy?

What is Narcolepsy?

Narcolepsy is a sleep disorder causing overwhelming day time sleepiness.This involves abnormal signalling from the brain.The eitiology of narcolepsy is not well understood even in the modern times.It may involve genetic factors.In Narcolepsy there is excessive daytime sleepiness, sudden muscle weakness, and disruptions in nighttime sleep. It is caused by the brain’s inability to regulate normal levels of the neurotransmitter hypocretin (also called orexin), which plays a key role in keeping people awake.It  is  a  long  term  neurological  condition  that  causes  excess  day  time  sleepiness.

Incidence  of  narcolepsy –

Interesting  the  United  States  it  is  50 percent  more  likely  to  affect  females  than  males .Around  1 in 2000 people  have  narcolepsy.Around  135000 to  2 lakh  people  in the  United  States  are affected  by  narcolepsy  at  any  time.

Eitiology of  Narcolepsy –

Till date  modern  medical science  does  not  know  the  cause of  narcolepsy.1-There are  possibilities  that  it  is due to the  deficiency  of  hypocretin or  orexin.These are  chemical substances  required by  brain  to  stay awake.Hypocretin  is produced  by  hypothalamus.It is  a  neurotransmitters.It  acts  on  various neurons  of the  brain  and  is responsible for  us to remain awake.Type  1 narcolepsy  has  low  levels  of  hypocretin.Type -2 narcolepsy  does not have hypocretin deficiency.In  this  there  is  excessive  day time  sleepiness  but usually  there is no  sudden weakness. 2-GeneticNarcolepsy  is  due to  combination of  genetic  and environmental  factors.It  runs in  families. 3-In  type -1 Narcolepsy  there is  deficiency  of  hypocretin.Hypocretin  is a  neurotransmitter.It is  produced  by  hypothalamus.Patients  with  type  1 narcolepsy  have  low  levels of  hypocretin.Patients  with  type  2 narcolepsy  do not have  low  levels of  hypocretin.Hypocretin  acts  various  neurons  of  brain  and  controls  whether  the  individual  will be  awake  or  asleep .When there is  deficiency of  hypocretin, the  brain  allows  REM sleep  phenomenon  to  intrude  into  normal waking  periods  and  so  the  individual  gets  excess  sleep  during  the  routine  awake  period of the  day  as  well as  night time  sleeping  problems.As  hypocretin is  produced  by  hypothalamus  of  brainAny  injury  to  brainAny  tumour  of  brainAny  condition  of  brain affecting  the  hypothalamus  will  affect  the  production  of  hypocretin  and  thus  lead to  narcolepsy.

Diagnosis  of  narcolepsy –

Any  patient  suffering  from  above  mentioned  problems  should  always  consult a  qualified and experienced  Neurologist doctor.You  should  enquire  in  the  region  where you  live as  to  which  Neurologist is  having  good  reputation.Things  have  occurred as  such  in  which  till  10 yrs  diagnosis  of  the  patient  could not be  made  and  then  patients have  consulted  10-15 doctors  in this period with  no  relief and the  misunderstanding  was  created  that the  patient  is  suffering  from -Restless legs  syndromeSleep  apnoeaSome psychological  disorderIn  any  case  accurate and  timely  diagnosis by  neurophysician is  very  important  so  that  treatment  can be  started  at the  earliest.The  neurologist  will  take  a thorough  medical  history,Will  do  a complete physical  examinationWill  conduct  sleep studies  likePolysomnographyMultiple sleep  latency  tests .During  polysomnography  the  patient  sleeps  in a  sleep  clinic  overnight and  the  polysomnography  machine  measures  the  sleep  patterns.The  multiple sleep  latency  test  is  done  after  polysomnography.

Symptoms of narcolepsy

Following  are the  symptoms of  narcolepsySymptoms of  narcolepsy  can  be  either  mild  ,moderate  or  severe.There  is  interrupted  night time  sleep.-The  main  symptom  is  excessive  daytime  sleepiness.REM (Rapid  eye  movement) sleep intervenes  during the  waking  periods of  day, resulting  in  excess  sleep  during the day  period.This  has effects on  the  social  activities and  overall  health  of the  individual.The  individual  can  fall  asleep  any  time  even  while  taking  or  driving.Cataplexy-Cataplexy is  the  sudden  weakness  of  the  muscles  of the  face  ,neck  ,knee.It  is  sudden  and  usually  lasts  for  less  duration  -around  2 minutes or  less but  it  can  lead  to  jaw drop,head drop, sudden fall and  accidents .The  individual  MA  collapse  to the  ground.Hypnagogic hallucinations .-These are frightening  sensory  hallucinations  which  occur  at the  time of  falling  asleep due  to  mixing  of  wakefulness  and  then  REM sleep during  which  dreaming occurs.

Sleep  paralysis.

When  an  individual  undergoes  sleep  process during night  he  first  enters  the  early  stage of  sleep ,and  then  the deeper  stages  of  sleep.REM  sleep  occurs  during  the  deeper  stages of sleep.This  usually  occurs  60-90 minutes  after  the  onset  of  sleep.In a  narcolepsy  patient  the sleep  cycle  at  night  is  disturbed  and  the REM  sleep  occurs  within 15 minutes  of  onset of  sleep cycle.It  also  occurs  in  the  routine  waking  hours of the  day.Dreams and  muscle  paralysis  occur  during  this  REM  stage of  sleep.

Types  of  narcolepsy –

It  is  of  2 types -a-Type 1 narcolepsy  andb-Type 2 narcolepsyIn  type  1 there  is  sleepiness  and  cataplexy .There  is  total  absence  of  neurotransmitter -hypocretin.This may  occur  after  an  infection  that  leads to  autoimmune  response.In  type  2 narcolepsy  there  is  no  sudden    weakness but  there  is  excess  daytime  sleepiness.As  discussed  earlier  in  this  article  secondary  narcolepsy  can  occur  when  there is  damage  to the  brain due to  trauma  or  brain  tumors  that  can  damage  the  hypothalamus  thus  affecting  the  hypocretin  production.The  total  duration  of  night sleep  in  a narcolepsy  patient  and  a  normal  individual  is  the  same.

Excessive  day time sleepiness –

Sleep  paralysis –

For  sleepiness –

The  individual  may  take  naps  of  15-20 minutes  throughout  the  day.Central  nervous  system  stimulants  are  advised  by  neurophysician  but  none  of  the  medicines  are  totally  effective.

For  Cataplexy –

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