The ‘word’ on Fibromyalgia, which was originally proposed to be a disorder of the muscles, has been that it’s a disorder of the central nervous system. Studies have found that both the pain-producing and the pain-inhibiting sides of the central nervous system in Fibromyalgia are clearly dysregulated. These are important findings, but they’re not the whole story. You wouldn’t know that from overviews of the disorder on the web where the central nervous system paradigm dominates.
Even the National Fibromyalgia Association makes no mention of the peripheral nervous system (although it does mention cytokines) in its overview of causes
over the past year it’s become clear that Fibromyalgia is not a brain or a body disorder: it’s both. Recent studies have found immune, autonomic nervous system, and muscle issues in FM. With this fourth study in the past year showing substantial damage occurring in the peripheral nervous systems, the body is back in the FM spotlight big time.
The lead author in this study, Dr. Xavier J. Caro, reported finding large-fiber neuropathy in FM patients in 2008 and was the first to report small nerve fiber problems in FM. His work with large fiber neuropathy was curtailed by the invasive, painful and costly nature of the testing, but then he turned to looking at small fiber neuropathy (SFN)’
In the study, Dr. Caro and Dr. Earl Winter state their interest in the peripheral (body’s) nervous system (as opposed to the nervous system in the brain) is really quite simple. When people with FM describe their symptoms they’re describing neuropathic or nerve problems. They note that the ‘language’ of FM can seem fantastic to the uninitiated (which has undoubtably contributed to the problems the disorder has had being taken seriously by the medical profession). Terms like ‘burning’, ‘stabbing’, ‘pins and needles’, ‘hot’, even just ‘miserable’ all describe nerve problems.
The lead author in this study, Xavier J. Caro MD, is a rheumatologist … and in 1989 he proposed that FM was in part an immune disorder.
More recent studies have found evidence of increased mast cell activation, changes in collagen structure, and increased cytokine levels in the skin.
Why the pain if the nerve fibers – the source of the pain – have been destroyed? Because they haven’t been completely destroyed and those that are still left are understandably upset (hyperexcitable) and they’re also communicating that upset to the secondary nerve fibers that are intact around them.
They bluntly stated that the two CNS factors primarily blamed for FM, wind-up and central sensitization (CS), are likely to be secondary rather than primary
They’re not saying that medications that reduce factors associated with central sensitization don’t work; they may reduce pain, but they play no role in reducing pain inputs from the periphery.
Dr. Caro stated that the treatment of FM is complex and that no two cases are alike but that in the main most Fibromyalgia patients require ‘immune modulators’ – an amazing statement given the current focus on the brain in FM.
If you’re thinking all this applies to FM and not to Chronic Fatigue Syndrome think again. Dr. Caro stated that he doesn’t really differentiate between the two.
Check out other small fiber neuropathy posts