Is fibromyalgia more like multiple sclerosis (MS) than we thought? A unique line of research is making it look that way.
First, a few things about MS. It's believed to be an autoimmune disease. Symptoms are caused by something called demyelination, which means destruction of myelin.
Myelin is a specialized cell that covers some nerves and is necessary for them to function properly. It's similar to insulation on electrical wires. A predominant theory is that, in MS, the immune system malfunctions and destroys the myelin sheath. Areas where the myelin is destroyed are called lesions.
Fibromyalgia & Demyelination
The 2008 research suggested that a subset of fibromyalgia involved autoimmune deymyelination and polyneuropathy (pain from damaged nerves.) It compared fibromyalgia to a neurological illness called chronic inflammatory demyelinating polyneuropathy, which is often treated with intravenous immunoglobulin (IVIg.)
In fact, in that study, they used IVIg to treat people from this fibromyalgia subgroup. Granted, it was a small study and that was only 15 people, but researchers say those people had significantly less pain and tenderness plus improved strength, along with smaller improvements in fatigue and stiffness.
This is a good example of how a preliminary study can have seemingly huge implications and yet have little or no impact. Yes, some doctors have used IVIg on patients, but it's far from a widespread treatment and demyelination in fibromyalgia is almost never discussed.
Fast forward six years, and at last we have a follow-up study that appears to confirm the earlier findings as well as advancing them. It's also supported by other work that's been done in the past few years.
First, the researchers wanted to explore whether the demyelination of large fibers (bigger nerves,) found in the earlier study, is caused by autoimmunity. Then, they also wanted to explore small fiber neuropathy, which has been suggested by other studies to be a part of fibromyalgia.
Small fiber neuropathy is painful damage to structures in the of the skin, organs, and peripheral nerves that provide sensation and help regulate automatic functions like heart rate and body temperature. Researchers were interested in it because it's known that small fiber neuropathy is sometimes associated with demyelination lesions on large fibers.
They found indicators of small fiber neuropathy, including diminished feeling in the lower legs. Also tested were multiple markers of immune activation and autoimmune activity.
Researchers discovered high indicators of small fiber neuropathy and therefore large fiber lesions, in the legs of people with fibromyalgia. They also found that these indicators, especially in the calf, appear to be linked to a marker of immune activation (interleukine-2R.)
They concluded that small fiber neuropathy likely contributes to our pain, and that some of our pain comes from immune-system activity, such as autoimmunity.
This follow-up study comes at a time when the interest of the fibromyalgia research community appears to be shifting toward small fiber neuropathy, inflammation, and possible autoimmunity. Taken in context, this work adds to the emerging picture that we do have damaged nerves after all, that our peripheral nervous systems are definitely involved, and that autoimmunity or another aspect of immunity is at work.
This was still a fairly small study, but the fact that it furthered earlier work and appears to gel with other recent research could mean that it'll have a bigger impact than its predecessor. At the very least, it seems that this is a worthy line of study that should continue.
Going back to the similarities with MS, I have a couple of thoughts: 1-If fibromyalgia is a close cousin to MS, it could really up the credibility. People know what MS is and they respect it. 2-Would MS treatments work for us? It would be great to see some of these established medications investigated for fibromyalgia. 3-The similarity makes sense, since we both can have flares and remissions and our symptoms are extremely similar.
Do you have or suspect neuropathy in your legs? Have you been treated for it? Has a doctor ever suggested IVIg as a treatment? Leave your comments below!
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