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Sleep Disorders

How can this possibly be `OSA`??



Hello, I have always been a "night owl"--never able to fall asleep until well after 1am, but once I feel asleep I was a solid sleeper. Lately my sleep has been exceptionally fragmented, and lots of EDS (falling asleep at work, at school, in the shower, etc). I take Ambien to go to sleep earlier in the evening, and even on 10mg of Ambien I still wake up 2-3 times at night. I was given 10mg Ritalin in the AM for the EDS, and had a sleep test done. Stage 1=2%, Stage 2=82%, Stage 3 and 4=0%, REM=16%. AHI=ZERO. RDI=11.6. Max 02=100%, avg during sleep=97%, min =95%. No Periodic Limb movements, No snoring. No AM headaches. I am young, female, lean weight and athletic. I also have some sleep paralysis and periodic hallucinations coming out of sleep. My dreams are exceptionally vivid (i sometimes have a hard time differentiating dream from reality), and I get many per night. I have allergies that I take Rx for, and tend to be a bit of an anxious person. Yet my Dr is ADAMANT that I have Obstructive Sleep Apnea. I`ve been on CPAP for over 2 months (100% compliant!) and no improvement in symptoms. In fact the CPAP has caused more problems with my ears/sinuses.

With results and symptoms like this, can it really be just OSA????


I am under the impression that you have done quite a bit of research regarding your sleep problems and you have provided almost complete information about your sleep study results. At this point, what I have to say is not going to be a surprise to you as I am sure you have run into some information about other disorders that can cause sleep problems, but I am glad you decided to write to us.

The main problem that you have is excessive daytime sleepiness. It is reasonable to look for a cause other than obstructive sleep apnea (OSA) syndrome since you have been on the treatment for this and have not noticed any change. Let’s discuss OSA first and then the alternatives one by one:

The Apnea-Hypopnea Index (the hallmark of OSA) can be somewhat variable from night to night. A single night sleep study may not determine the AHI accurately in about 15% of the cases. But since you have been on the treatment for an adequate duration of time, and since you have been compliant without change in symptoms, it would be unlikely that sleep apnea is the problem. I am, of course, assuming that the treatment you have used is effective, because sometimes the pressure on the CPAP machine may not be set correctly.

Upper Airway Resistance Syndrome (UARS), measured by the Respiratory Disturbance Index (RDI), has no standard approach to diagnosis, though frequently the sleep study can offer a suggestion that this may be present (to truly diagnosis this condition, a sleep study with a probe in the esophagus is needed and most centers do not do this kind of testing). The treatment for UARS is essentially the same as for OSA and CPAP should have worked. So I will leave this issue alone.

Chronic sleep restriction (which is a widespread problem) is the most important cause of sleepiness in the general population. Seven to eight hours of sleep per night are usually needed for most people to feel refreshed. This sleep should occur in a comfortable (cool, dark, and quiet) environment. Some individuals are “long sleepers”, which means that more than 8 hours are needed for them to feel refreshed. You confess that you are a night owl and that your sleep is fragmented. This puts you at higher risk of sleep deprivation if you are not careful in monitoring your sleep hours.

Many medications and substance use can cause sleepiness. You mention using allergy medications. All antihistamines, including the non-drowsy ones, cause some degree of sleepiness. And, paradoxically those drugs can cause irritability and sleep disturbance as they are metabolized out of the body. Also, a significant number of over the counter medications, in addition to alcohol, and tobacco, can cause sleep and wake disturbance. This can be tested by stopping any substances and looking for an improvement in symptoms.

There are multiple chronic medical conditions that can cause sleep and wake disturbance. A general medical history and exam with few laboratory tests should be sufficient to rule out major problems that may affect your general health including sleep and wake.

And finally, there is Narcolepsy and its elusive cousin: Idiopathic Hypersomnia. Both disorders are related to excessive daytime sleepiness. However, the extra symptoms that you describe are remarkable, and happen to be suggestive of Narcolepsy. Namely, sleep fragmentation, sleep-related hallucinations, and sleep paralysis. Although cataplexy (sudden loss of muscle tone with extreme emotions) is not necessary for the diagnosis of narcolepsy, it is often missed as a symptom if not directly sought. The diagnosis and treatment of these disorders is complex and need to be discussed in detail with a Sleep Medicine specialist.

As you can see, there are many possibilities and an evaluation by a Sleep Medicine specialist is necessary at this point. But, in short, you are correct. What your symptoms may not all be due to OSA and additional careful evaluation should be considered.

I would like to direct you to the web site of the American Academy of Sleep Medicine for information about Sleep Centers across the country so you can locate one near you and start the necessary evaluation. Please don’t hesitate to let us know of any progress in your story.

I wish you best of luck.

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Response by:

Ziad  Shaman, MD Ziad Shaman, MD
Assistant Professor of Medicine
School of Medicine
Case Western Reserve University