The Causes of Fibromyalgia by Cort Johnson
Triggering Fibromyalgia:
Trauma / Infection / Psychological and/or Physical Stressors:
It's not surprising that injuries can trigger
FM but it intriguing that other 'stressors' such as infections (hepatitis
C, coxsackie B, HIV, parvovirus) can as well. How such a process occurs is still unclear
but researchers are increasingly focused on the central nervous system and
the ways that stressful events such as injury and infection can affect it
functioning.
Activation of the Pain Producing Pathways in the Brain: Increased levels of
three-pain producing substances have been found in FM. Substance P, the most
well-studied pro-pain substance is associated with increased pain, anxiety,
stress, nerve damage and nausea. High levels of these factors suggest the
neural pathways responsible for producing pain have become chronically
activated or ‘sensitized’ in FM.
Inhibition of the Pain Inhibiting Pathways in the Brain: In addition to
increased levels of 'pro-pain' factors FM patients also have low levels of
several 'anti-pain' factors. This conjunction of increased pro-pain and
decreased anti-pain factors suggests FM patients 'get it' from both
directions; their pain producing pathways are overactive while the neural
pathways that are supposed to quiet the pain response down are under active.
Low Serotonin Activity:
Many of the central nervous system abnormalities
found in FM occur in areas of high serotonin activity. Serotonin is also
important in areas other areas of the body sometimes affected in FM such as
such as the circulation and the gastrointestinal system. FM patients have
been found to display low levels of serotonin and its precursor
(tryptophan), and increased mutation rates in several genes involved in
serotonin activity. One study found reduced numbers of the proteins that
transport serotonin into the cell.
Increased Sympathetic Nervous System Activity/Impaired Microcirculation:
The idea that low blood flows to the muscles play a role in FM was raised
over 30 years ago but only recently have researchers been able to accurately
measure microcirculatory blood flows. Reduced microcirculatory blood flows
in FM may occur when increased SNS activity causes the blood vessels to
narrow, thus reducing blood flows to the tissues. This could result in a
state called 'ischemia' which is known to increase the sensitivity of pain
receptors in the tissues.
Immune Activation: Infections may trigger FM through the
production of pro-inflammatory cytokines that activate the neural pathways
involved in pain and other sensory processes.
HPA Axis Dysfunction: The activity of the main hormonal stress response
system (the HPA axis) appears to be inhibited in FM patients. Several of the neurohormones involved in the HPA axis activity play a role in pain
perception. Just as in chronic fatigue syndrome it is unclear whether
reduced HPA axis functioning is a cause or effect of FM.
Summary: Fibromyalgia is a complex disease involving abnormalites in the
neural pathways producing pain, the regions of the brain involved in
processing sensory data and perhaps both arms of the stress response system
(HPA axis, sympathetic nervous system).
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