Narcolepsy Vs idiopathic hypersomnia-do we need to care?

Two half days a week I see patients in the sleep center. One of the reasons patients come to see me is for excessive daytime sleepiness (EDS). Patients may voice the above complaint in different ways. Some say [Dr. Sethi my biggest problem is that I feel sleepy during most of the day. I find it hard to concentrate at work or my mind feels "dull"]. Others may say they find it difficult to wake up in the morning in time for work or college. The history may be more worrisome: the patient may have fallen asleep while driving. So how does one differentiate between the various causes of EDS? In this post I shall touch on these very topics.

The various causes of EDS can be broadly listed as follows:

1. Untreated sleep disordered breathing: Obstructive sleep apnea (OSA), Central sleep apnea (CSA), Mixed sleep apnea (MSA).

2. Poor sleep hygiene

3. Circadian rhythm disorder: Delayed sleep phase syndrome (DSPS), Shift work disorder

4. Narcolepsy: primary and secondary

5. Idiopathic hypersomnia.

6. Medical disorders causing poor sleep at night.

Narcolepsy: is characterized by excessive sleepiness. It may or may not be associated with cataplexy. Cataplexy in simple terms refers to loss of muscle tone. Let me explain with the aid of an example. Let us assume a narcoleptic patient hears a joke. He starts laughing and suddenly experiences loss of muscle tone and finds himself on the ground. This sudden loss of muscle tone is referred to as cataplexy. Another example of cataplexy is a runner who collapses when the starter gun goes off. Narcolepsy is usually accompanied with sleep paralysis and vivid hallucinations which are reported either at onset of sleep or when the patient is about to wake up (that is around sleep-wake transitions). A point to note is that if the patient has cataplexy then the diagnosis of narcolepsy is easy to make. It is narcolepsy without cataplexy that is tough to diagnosis. A caveat to remember here is that not “everything” is cataplexy-so weakness in the knees if you have been laughing hard does not constitute cataplexy. Narcolepsy occurs due to the loss of hypocretin neurons in the lateral hypothalamus. So secondary narcolepsy may also occur if these neurons are damaged by a hypothalamic stroke or a hypothalamic tumor or by a infectious/ inflammatory process (limbic encephalitis). The clinical presentation of secondary narcolepsy though is different: example the history is of excessive sleepiness after a stroke or a tumor.

The diagnosis of narcolepsy is made on the basis of an overnight polysomnography (sleep study) which is done to rule out sleep disordered breathing (sleep apnea). One needs to make sure that the patient does not have untreated sleep apnea before the EDS can be attrbuted to narcolepsy. The patient also undergoes a test called multiple sleep latency test (MSLT). During the MSLT the mean sleep latency is calculated. In narcoleptics the mean sleep latency is usually less than 5 minutes and they also have sleep onset REMs (meaning they enter REM sleep as soon as they fal asleep). This is against what is seen in idiopathic hypersomnia which too has a short sleep latency but there is no sleep onset REMs.

The treatment of narcolepsy and idiopathic hypersomnia is virtually identical. The patient is usually prescribed stimulants such as Adderall, modafinil (Provigil) or Nuvigil.

In my next post I shall elaborate on this further.

Nitin Sethi, MD

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12 thoughts on “Narcolepsy Vs idiopathic hypersomnia-do we need to care?

  1. I am trying to research the possible origin of EDS and difficulty concentrating, and mental dullness and personality change that my wife has been experiencing since she suffered an episode of prolonged acute hypertensive encephalopathy one year ago. She was treated in the ED, for this state, during which her Hypertensive emergency began with her being lucid and after a very slow response to the treatment of her hypertensive state her mental status became first, babbling and eventually incoherent and then comatose. She awoke 24 hours later apparently lucid but slightly confused. Over the next year her complaint is progressively worsening EDS, sleeping all night and much of the day,unable to concentrate and feels dull and no longer able to interact with friends and fellow workers. She is an RN, 57 y/o, she does not seem to have sx c/w sleep apnea. She is on Metoprolol 50 bid,Prazosin 2mg tid, norvasc 5 qd, also on Amaryl 4 mg bid and Januvia 100mg qd for DM II, Lipids controlled by Crestor 20 qhs. Also takes Lexapro 20mg qd and Reglan 10 tid. I am an Internal Med MD, do you have any suggestions for us?

    • Dear Dr. Goldberg,
      thank you for writing in to me. It is Friday afternoon here in NYC and I was just about heading out of the hospital but I wanted to send you a quick email. A couple of thoughts that come to my mind as a neurologist who also does sleep medicine for 2 half days. Your wife’s symptoms started after an episode of acute hypertensive encephalopathy. Did she have PRESS ( posterior reversible encephalopathy syndrome) or RCVS (reversible cerebral vasoconstriction syndrome)? Where FLAIR or T2 changes noted on her MRI brain. If yes what areas did they involve. Could she have developed secondary narcolepsy (due to destruction of orexin producing neurons in the lateral hypothalamus0 or does she have a disorder of arousal/ consciousness due to some involvement of the ascending reticular activating system or deep grey nuclei (thalamus) injury.

      A good quality MRI of the brain shall give us some of the above answers. Further what does her EEG show now? Does it show a normal alpha frequency background or does it show diffusely slowing even in the wake state. As for the excessive daytime sleepiness a overnight polysomnography (sleep study) to rule out sleep apnea followed by a multiple sleep latency test (MSLT) shall be helpful. Once we figure those answers out–giving her Modafinil may be a consideration.

      Some of my thoughts. If you need any further help, feel free to email or call me Dr. Goldberg.

      Personal Regards,

      Nitin Sethi, MD

      • Thank you, Dr. Sethi, for taking the time at the end of the day, to review my wife’s case.I must admit that, although she had a neurological consultation and did have a brain MRI, only a lacunar infarct was reported and the neurologist did not suggest whether she had PRESS or RCVS. I will obtain her records and look more closely at them. She has not had neurological follow up and has not had an EEG. I will arrange to have the studies (EEG, polysomnography and MSLT). Thank you again for your very prompt reply. I will inform you as we acquire more data. Have a wonderful weekend. Joe, MD

      • You are very welcome Dr. Goldberg. If you so desire I shall be happy to talk to you on the phone. Maybe I shall be able to give you a few thoughts that might be helpful.

        Personal Regards,

        Nitin Sethi, MD

  2. Dear Dr. Sethi,

    I have excessive daytime sleepiness. I’ve had it for 10 years. I was thought to have narcolepsy and was treated successfully with Provigil and Adderall together, until I had a sleep study. It did not show narcolepsy.

    My symptoms began following dental sedation for wisdom tooth extraction. I had an unusual reaction to the anesthesia and they were unable to wake me up. I had to be carried out to the car. I couldn’t talk and didn’t regain normal consciousness for at least 8 hours.

    I’m wondering if the nitrous oxide could have caused some sort of damage that resulted in the constant sleepiness I now experience, or if my reaction to anesthesia was a manifestation of some underlying disorder.

    I’ve never mentioned to my doctors that this started after the dental procedure, nor have I ever explained my unusual reaction to my doctors. Do you think it’s worth mentioning. It seems that nobody cares about my symptoms anymore, they just care about the results of my sleep study. Since that didn’t show narcolepsy, people basically act like I’m crazy and making all of this up and don’t deserve treatment.

    • I was diagnosed with idiopathic hypersomnia about seven years ago. I’ve always pondered over what may have caused my symptoms. Immediately after reading your post I called my mom and we agreed I should ask my doctor about it next week: I had my wisdom teeth removed when I was eleven, and experienced the same exact reaction (my mother carried me to the car and I slept for a day and a half). Let me know if you ever learned anything about this possible connection.

      Thanks

  3. Hello,
    I just wanted to write to Doctor Sethi I was diagnosed at the end of last year with Narcolepsy with Cataplexy. It has really messed up things for me. I lost my job which I am very upset about I’ve got to find another job not sure what job I should try for. My husband has been wonderful he is so good to me. I wish I did not have Narcolepsy because I feel I am very limited on what I can do. Write now I am not working my husband doesn’t want me to drive right now until I see my Neurologist in June. I understand that but I don’t want it taken away from me. One of the worst things of Narcolepsy I don’t know why I have it but God has a plan. But my attention span is the pits I forget things I will be telling my husband something and I forget what Im going to say I have headaches they are not fun I just feel awful somedays. One thing I will run by you I will be sitting on the couch in the evening and I will go to sleep without warning and I won’t wake up for several hours. When I do wake up sometimes by husband is standing in front of me and he says I tried to wake you up and he cannot wake me up no matter what he does he tickles my feet kind of hard he says he gets a hold of my legs and and rubs them real hard and he can never wake me up anything he tries he just has to wait until I wake up on my own and my dog can’t even wake me up.

    I am on Nuvigil right now it help at first but right now its not. I am 30 yrs old and I would like me and my husband to have a baby in the near future but I don’t know if I will. If you could please give me some insight on this I would very much appreciate it thank you

    C

  4. Sarah,, I as well have idiopathic hypersomnia and was diagnosed in 1999 when I was a sophmore in college. It was noted that my “onset” symptoms were triggered when I had Mono as a senior in high school. As my parents thought I was partying too much as a freshman in college they ignored my constant complaints that I was exhausted and sleeping through class until I stayed with them between my freshman and sophmore years and slept for three days straight. They stated they kept waking me to eat but that I kept falling back asleep before even getting up to eat. It is treated the same and I dont know really that I understand the difference between narco. and idiopath. hypers. but I have always been treated the same. Many people say that it lays dormant in your body until some Body or Mind jolting wakes it up and brings it out. Something such as a serious illness or fever or mental situation or trauma.

  5. I really need help. I can stay awake for hours on and I can sleep for hours and on end. I set 3 alarms to wake me yet they do not. I have fibromyalgia and ADD but I’m not on meds for it. My Dr. Has me on Amitryptaline 50mg. I take it at 900 I went to bed at 5am. Idk what to do. I think I only stay awake because I’m scared I won’t wake up on time. The first antidepressant made me suicidal. This one gives me night terrors. I figure that if she gives me Adderal then it would help both the sleep and add. I think that my mind is so busy that it won’t shut off so when it does it does. I sleep so hard that my husband has sex with me while I’m sleeping and I don’t wake up. I wake up with anxiety because I never know why time or how long I sleep.

    • Hello Lora,
      likely what you are suffering from is a combination of poor sleep hygiene, a lack of a well entrained circadian rhythm (delayed sleep phase syndrome) and psychophysiological insomnia. These disorders when they occur in some combination in the same person can be extremely difficult to treat and very distressing to the patient. If it is possible make an appointment to see a sleep medicine doctor. You may look up Sleep Centers near you and make an appointment. There these issues can be addressed in a comprehensive fashion. I wish you good health.

      Nitin K Sethi, MD

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