MED,RES: Norepinephrine-evoked pain in fibromyalgia. A randomized pilot study [ISRCTN70707830]

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Research article

Norepinephrine-evoked pain in fibromyalgia. A randomized pilot study

[iSRCTN70707830]

ez-Lavin , Marcela Vidal , -Elda Barbosa , Pineda ,

- Casanova and Arnulfo Nava

Rheumatology Department Instituto Nacional de Cardiología Ignacio Chávez.

Badiano 1, 14080 Mexico D.F. México

BMC Musculoskeletal Disorders 2002 3: 2

This article is available from: http://www.biomedcentral.com/1471-2474/3/2

Received 8 Oct 2001

Accepted 16 Jan 2002

Published 16 Jan 2002

© 2002 ez-Lavin et al; licensee BioMed Central Ltd. Verbatim copying

and redistribution of this article are permitted in any medium for any

purpose, provided this notice is preserved along with the article's original

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Abstract

Background

Fibromyalgia syndrome displays sympathetically maintained pain features such

as frequent post-traumatic onset and stimuli-independent pain accompanied by

allodynia and paresthesias. Heart rate variability studies showed that

fibromyalgia patients have changes consistent with ongoing sympathetic

hyperactivity. Norepinephrine-evoked pain test is used to assess

sympathetically maintained pain syndromes. Our objective was to define if

fibromyalgia patients have norepinephrine-evoked pain.

Methods

Prospective double blind controlled study. Participants: Twenty FM patients,

and two age/sex matched control groups; 20 rheumatoid arthritis patients and

20 healthy controls. Ten micrograms of norepinephrine diluted in 0.1 ml of

saline solution were injected in a forearm. The contrasting substance, 0.1

ml of saline solution alone, was injected in the opposite forearm. Maximum

local pain elicited during the 5 minutes post-injection was graded on a

visual analog scale (VAS). Norepinephrine-evoked pain was diagnosed when

norepinephrine injection induced greater pain than placebo injection.

Intensity of norepinephrine-evoked pain was calculated as the difference

between norepinephrine minus placebo-induced VAS scores.

Results

Norepinephrine-evoked pain was seen in 80 % of FM patients (95% confidence

intervals 56.3 – 94.3%), in 30 % of rheumatoid arthritis patients and in 30

% of healthy controls (95% confidence intervals 11.9 – 54.3) (p < 0.05).

Intensity of norepinephrine-evoked pain was greater in FM patients (mean ±

SD 2.5 ± 2.5) when compared to rheumatoid arthritis patients (0.3 ± 0.7),

and healthy controls (0.3 ± 0.8) p < 0.0001.

Conclusions

Fibromyalgia patients have norepinephrine-evoked pain. This finding supports

the hypothesis that fibromyalgia may be a sympathetically maintained pain

syndrome.

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Full article downloads at:

http://www.cfsresearch.org/fib/2.htm

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Dear NVE,

It strikes me that " that " woman who said those disparaging remarks

about us " fibros " should be forced to read that article (and the

other ones you share with us here)!

Thanks for all your work,