Chiari's Many Faces Of Sleep Disturbance

May 31st, 2009 - Sleep apnea is a condition where an individual stops breathing during sleep for a period of one or more breaths. Clinically significant sleep apnea is defined as 5 or more of these episodes in an hour. Individuals with this condition experience fatigue during waking hours but are rarely aware that they have the condition. There are three basic types of sleep apnea - obstructive, central, and idiopathic. Obstructive sleep apnea is the most common and is usually caused by soft tissue blocking the windpipe. Excessive weight is a significant risk factor for obstructive sleep apnea. Central sleep apnea can have many causes but is often the result of brain stem lesions or compression to the brainstem. It is far less common than the obstructive type in the general population. Idiopathic is the term used for unknown causes of apnea.

It is well documented that Chiari can cause central sleep apnea. The incidence of clinically significant central sleep apnea in patients with Chiari varies widely from study to study. The reason for this is because diagnostic criteria for Chiari have evolved dramatically over the past 20 years. In older studies, the reported incidence was high (40% or more). More recently, with Chiari diagnostic criteria redefined resulting in an increased number of patients overall, the incidence of central sleep apnea is considerably lower and more in the neighborhood of 5%. In very rare cases, central sleep apnea associated with Chiari can result in death. It is therefore very important for Chiari patients to get a sleep study done if apnea is suspected or day time fatigue is significant.

According to a paper published by Oro and Mueller1 in 2004, seventy-two percent of 265 Chiari patients studied prospectively presented with sleep difficulties other than sleep apnea. These patients reported trouble sleeping due to pain, anxiety, and difficulty breathing when lying down. Some also reported generalized insomnia as well as hypersomnolence (10 or more hours of sleep per day). Other than this paper, there are no other publications in the medical literature reporting non-apnea sleep problems associated with Chiari. The reason for this is because other studies never asked patients about sleeping problems.

During the many years I suffered from Chiari prior to diagnosis and decompression, I experienced a period of about 9 months where I required 12 or more hours of sleep a day and found it extremely difficult to stay awake. I also experienced and continue to experience even after decompression generalized insomnia. When I first told my doctors about my sleeping difficulties, it was pretty much dismissed. One experienced neurosurgeon told me that she had had no other Chiari patients complain about insomnia. And, since I couldn't find anything in the literature at the time, I felt that I was the odd man out so to speak in wondering if my insomnia was related to Chiari. Today we know that it is actually very common to see sleep disturbances with Chiari which makes a strong case for evaluating sleep in the diagnostic workup for Chiari. Pinning down the cause of sleep problems however requires a good sleep specialist. In addition to the reasons reported in the Oro and Mueller paper, insomnia can also be caused by depression which tends to manifest itself as early awakening. And many of the types of medications often used to treat the symptoms of Chiari can cause either insomnia or somnolence.

What is very intriguing however is the fact that certain brain tumors that result in increasing pressure to parts of the brain near or on the brainstem/upper spinal cord are known to result in a variety of non-apnea sleep disturbances. In taking a quick look at the medical literature, I located eight references in which tumors affecting parts of the brain like the third ventricle, the clivus, and the pons resulted in insomnia, hypersomnolence, and sleep parameter changes.

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For example, in the case2 of a 55-year-old man with a gangliocytoma filling the third ventricle, hypersomnolence was observed. The individual also exhibited increased appetite and memory impairment. In another case3 involving a 40-year-old man with a clival chordoma, pathological laughter during sleep was observed and his sleep patterns were similar to those of experimental animals with similar brain lesions. Selective disorganization of REM (Rapid Eye Movement) sleep was observed in yet another case4 involving an infiltrating tumor of the pons.

Sleep is one of the most complex functions of the human body. Obviously, sleep can be disrupted in many ways by all sorts of brain tumors. Since Chiari can result in increasing pressure to a wide variety of brain structures it can be expected to disrupt the normal sleep pattern in a wide variety of ways as was observed by Oro and Mueller. Further clinical research in this area is sorely needed. Some useful data may already exist which could provide important guidance. Here I am referring to the fact that many Chiari patients have already had sleep studies, most of them for the purpose of diagnosing sleep apnea but a significant number without sleep apnea as well. These data could be collected and analyzed retrospectively to obtain a preliminary categorization of sleep disturbances observed in the Chiari population. Understanding these categories and how to spot them during sleep studies could be useful in guiding treatment to Chiari patients suffering from sleep problems other than apnea and insomnia due to anxiety and depression.

Sleep studies are totally painless and most sleep study clinics are very private and comfortable. If you feel fatigued during the day or your partner tells you that you are holding your breath at night or snoring excessively, talk to your doctor about getting a sleep study.

References:
1
J Am Acad Nurs Pract. 2004 Mar;16(3):134-8.
2
Neurology. 1981 Oct;31(10):1224-8.
3
J Neurosurg. 1993 Sep;79(3):428-33.
4
Electroencephalogr Clin Neurophysiol. 1975 Feb;38(2):203-7.


Ed. Note: The opinions expressed above are solely those of the author. They do not represent the opinions of the editor, publisher, or this publication. Mr. D'Alonzo is not a medical doctor and does not give medical advice. Anyone with a medical problem is strongly encouraged to seek professional medical care.