Is Fibromyalgia(FM) a Small Fiber Neuropathy?

Recent poster studies shows decreased nerve density peripherally in FM.

My Daughter and I are doing a survey of women with Fibromylagia. If you have Fibromyalgia, could you be so kind as to click  here:  Survey

IASP Poster Presentation Number: PW 093, Montreal 2010
N. Üçeyler1, S. Kewenig1, J. Zeller2, A. J. Fallgatter2, C. Sommer1

  • biopsies proximal thigh and lower leg
  • Controls has an intraepidermal (skin) nerve density of 9.5 nerves/mm; Fibromyalgia victims have 5 nerves/mm;  p<0.0001). Associated with “impaired small fiber function in QST [Quantitative sensory testing] (p<0.0001).” – CDT = cold detection threshold; WDT = warm detection threshold; TSL = thermal sensory limen (alternating warm – cold reactivity);
  • Is this significant ? – Yes

Journal of Neurology Volume 256, Number 7, 1067-1075
The value of skin biopsy with recording of intraepidermal nerve fiber density and quantitative sensory testing in the assessment of small fiber involvement in patients with different causes of polyneuropathy Maria Nebuchennykh, Sissel Løseth, Sigurd Lindal and Svein Ivar Mellgren abstract here

They found a density below 6.7  had a specificity for small fiber neuropathy of 95%. – so 5 certainly counts

This would put Fibromylagia in the same footing as Diabetic neuropathy!

What are the symptoms of small vessel neuropathy? a good reference is this article from Cleveland Clinic:
Small fiber neuropathy: A burning problem
Cleveland Clinic Journal of Medicine May 2009 vol. 76 5 297-305 free article here

The authors state: “Symptoms are pain, burning, numbness, and autonomic dysfunction (lack of sweating) in the hands and feet in a stocking-glove distribution. Strength is not affected. Tendon reflexes are normal, as are nerve conduction studies.”

Now think about this – reflexes and strength are normal and nerve studies are normal. If someone with Fibromyalgia complained of any of these symptoms and had normal tests otherwise – would they be taken seriously?  I suspect the symptoms would be ignored as being part of the “psychosomatic illness”…

So where does this neuropathy come from? Well, I hate to sound like a broken record – but cytokines are implicated:
Nature Reviews Neurology 6, 416 (August 2010) |
Pain: Do cytokines cause pain in small-fiber neuropathy?
Nick Jones  abstract here

Cytokines are being implemented in a variety of pain conditions:
Cytokine Inflammation Diseases Will Be the Diseases of the 21st Century

Chronic Pain May be A Cytokine Inflammation Disease

Comment – Fibromyalgia is quickly becoming a skin disease – too many mast inflammatory cells (5-10 versus only 0-1 in “normals”as per:
Is Fibromyalgia a Mast Cell Disease – like some “somatization diseases” such as migraine, TMJ, irritable bowel, and interstitial cystitis

and now deterioration of skin small nerves.

Retroviruses like HIV (AIDS) are associated with small fiber neuropathy. There is now growing evidence there could be a retroviral Murine Leukemia Virus associated certainly with chronic fatigue,

Murine Leukemia Viruses Common in Chronic Fatigue

How could one suspect they had it?

It would be a good bet if one had restless leg syndrome – common in FM; restless legs are known to have a small fiber neuropathy connection:
Subclinical sensory neuropathy in late-onset restless legs syndrome
M Polydefkis, RP Allen, P Hauer, CJ Earley, JW
Neurology 2000;55:1115-1121  abstract here

The plot thickens but it certainly does not lead to it being all in their head..

any comments?

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3 Responses to Is Fibromyalgia(FM) a Small Fiber Neuropathy?

  1. George says:

    Its also associated with increased mast cell density in the skin.

  2. Pingback: Fibromyalgia (FM) Cases with Tingly, Funny Feelings – How Can You Tell If You Have a Small Fiber Neuropathy Instead? | Pain Medical Musing

  3. Pingback: Fibromyalgia – Further Elucidation of Small Fiber Neuropathy Presence. | Pain Medical Musing

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