Norepinephrine-evoked pain in fibromyalgia. A randomized pilot study ISCRTN70707830
Norepinephrine-evoked pain in fibromyalgia. A randomized pilot study ISCRTN70707830
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DOI：
10.1186/1471-2474-3-2
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发表时间：
2002-01-01
影响因子：
2.3
通讯作者：
Nava, A
中科院分区：
文献类型：
--
作者：
Martinez-Lavin, M;Vidal, M;Nava, A
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.
