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.
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 –
- Due to excessive daytime sleepiness the patient of narcolepsy may experience –
- Decreased energy
- Memories lapse
- Brain fog
- Poor concentration
- Hypnogogic hallucinations -These are vivid frightening sensory hallucinations which can occur during sleep .
- In Cataplexy there is sudden muscle weakness that affects the face, neck, and knees.
- Some people will have only mild weakness, such as a head or jaw drop, but some may collapse to the ground.
- This weakness is transient lasting for 2 minutes or less, but it can lead to falls and other accidents.
- Triggering factors include strong emotions, such as surprise, laughter, or anger.
Sleep paralysis –
- In this the narcolepsy patient is not able to move or speak during falling asleep or during waking up and duration of these episodes vary from few seconds to several minutes.
- This is transient and the individual recovers later.
- Treatment of narcolepsy
- At present there is no cure for narcolepsy.
- Till date there are several diseases and disorders for whom there is no treatment in modern medicine.
- Narcolepsy is one of these.
- So it is entirely the luck of the individual.
- Medical treatment and lifestyle changes can just help.
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.
- First choice of treatment is given to Modafinil and Armodafinil ,as the other drugs are having side effects like
- Habit forming
- Changes in heart rhythm ,etc.
For Cataplexy –
- Sodium oxybate is given.
- It is used in the treatment of excess day time sleepiness ,night time sleep disturbances and cataplexy.
- If antidepressants are given for cataplexy they can cause side effects like hypertension and changes in heart rhythm.
- For improvement in quality of life –
- The patient should get emotional support from his family members.
- Mental health counselling should be done
- Disability formalities should be completed .
- Driving or machinery must be avoided.
- Regular sleep schedule should be followed.
- Regular physical exercise minimum 20 minutes per day.
- Avoid caffeine or alcohol several hours before going to bed.
- Avoid smoking, especially before bedtime.
- Avoid eating heavy meals near bedtime.
- At the present time research is still going on on narcolepsy so as to find effective cure for it.