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Ask the Doctor
By R. Norman Harden, MD
Director, Center for Pain Studies, Addison Chair, Rehabilitation Institute of Chicago, Chicago, Illinois
We get many queries from our members looking for information.
We asked R. Norman Harden, MD, Clinical Co-chair of the RSDSA
Scientific Advisory Committee, to comment on some of them.
Dr. Harden would like to emphasize that the comments that
follow are based solely on clinical observations since there
have been no epidemiologic studies conducted on these topics.
Are sleep disorders common in people who have CRPS?
Yes, I would say that at least 75% of people with CRPS,
possibly as many as 90%, have some sort of sleep disorder.
Pain is, of course, the main culprit for those who have difficulty
falling asleep and for those who have difficulty staying asleep.
At bedtime, the mind starts to relax, and since there are
no distractions the mind naturally focuses on pain. Early
morning awakening may occur if a person rolls onto the affected
limb and is awakened by pain.
Treating the sleep disorder is critical, not only because
people who sleep well feel better, have more energy, and are
in a better mood, but sleep is critical to the body's recuperation,
repair and healing, especially with chronic disease. Repair
and some parts of the recuperation process occur only during
sleep; for instance, 90% of Somatamedin C, a hormone that
is critical in maintaining nerve and muscle health, is produced
in deepest stages of sleep. If you don't make Somatamedin
C, you are not going to repair tissues from normal wear and
tear, which in turn causes more pain. It is a vicious circle.
People in chronic pain don't get into these deep stages of
sleep so essential to healing, and Somatomedin C is only one
example of critical neuroendocrine products produced during
sleep.
We treat sleep disorders very aggressively. and try to use
agents that hit "2 or 3 birds with one stone." For
example, some of the antidepressant drugs (such as nortriptaline
or doxepine) are actually great analgesics. The brain stem
(where you produce several critical neurochemicals such as
serotonin and norepinephrine. coordinates pain, sleep, and
mood. These "antidepresseant agents" modulate serotonin
and norepinephrine, critically important for quality and quantity
of sleep, normal mood and pain modulation. Since you only
have to take these agents once a day you can use them as anti-insomnia
agents as well as analgesics to help initiate sleep, prolong
it, improve the quality of sleep, and relieve the pain.
The Stages of Sleep
There are five stages of sleep that cycle over and over again
during a single night: stages 1, 2, 3, 4 and REM (rapid eye
movement).Stages 1 through 4 are also known as non-rapid eye
movement sleep (NREM). Approximately 50% of our sleeping time
is spent in stage 2 and 20% in REM. A complete sleep cycle,
from the beginning of stage 1 to the end of REM, usually takes
about 90 minutes. An adult normally sleeps more than 2 hours
a night in REM.
Stage 1: a light sleep during which the muscles begin to relax
and a person can be easily awakened.
Stage 2: brain activity slows down and eye movement stops.
Stages 3 and 4: deep sleep, during which all eye and muscle
movement ceases. It can be difficult to wake a person during
deep sleep. Stage 3 is characterized by very slow brain waves
(delta waves), interspersed with small, quick waves. In stage
4, the brain waves are all delta waves.
REM: It is during REM sleep that people dream. The muscles
of the body stiffen, the eyes move, the heart rate increases,
breathing becomes more rapid and irregular, and the blood
pressure rises.
www.neurologychannel.com/sleepdisorders/
Updated May 19, 2004
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