Hypothalamic-pituitary-adrenal stress axis in fibromyalgia

Discussion in 'Fibromyalgia Main Forum' started by fibromaster, Aug 10, 2005.

  1. fibromaster

    fibromaster New Member

    Hypothalamic-pituitary-adrenal stress axis function and the relationship with chronic widespread pain and its antecedents.

    In clinic studies, altered hypothalamic-pituitary-adrenal (HPA) axis function has been associated with fibromyalgia, a syndrome characterised by chronic widespread body pain. These results may be explained by the associated high rates of psychological distress and somatisation. We address the hypothesis that the latter, rather than the pain, might explain the HPA results.

    Fibromyalgia is a common syndrome of which chronic widespread body pain is the cardinal feature [1]. We have previously shown in a community-based prospective cohort study, the Altrincham Pain Study, that psychosocial factors, including reporting other non-pain somatic symptoms, aspects of illness behaviour and high levels of psychological distress and fatigue, were the strongest predictors of the onset of chronic widespread pain [2]. The biological processes through which these psychosocial risk factors may lead to pain, however, are unknown.

    One hypothesis, although the link is debated [3,4], relates to altered function of the hypothalamic-pituitary-adrenal (HPA) stress axis [5]. Specifically, clinic patients with fibromyalgia have been reported to have hypoactive HPA axis function, with several studies showing reduced basal plasma cortisol, decreased 24-h urinary free cortisol excretion [6-9] and a blunted response to dynamic testing [9-11], Further, pain sensitivity is inversely related to the level of activation of the HPA system's response to stress. The hypoactive HPA axis response of fibromyalgia patients is more marked when compared to that of other chronic pain patients with less widespread symptoms, including those with rheumatoid arthritis [7] and non-inflammatory low back pain [9]. These findings are equivocal, however, with some investigators reporting that patients with fibromyalgia display hyperactive HPA responses [7,8,12,13].

    The nature of the relationship between chronic widespread pain and HPA axis function is therefore unclear and remains to be clarified. The studies discussed above were conducted on small numbers of patients, which may have had an impact on the accuracy of the findings. More importantly, subjects with chronic widespread pain, when compared to pain free controls, have increased rates of other symptoms, including high levels of psychological distress [14], notably depressive disorders [15], which are associated with altered HPA axis function. Indeed, mood disorders are even more apparent in those who consult with pain [16]. We have conducted a study to investigate the independent effects of pain and psychological distress in relation to the HPA response.

    Clinic based studies have suggested that persons with chronic widespread pain display altered HPA axis function. Due to small numbers of subjects and the presence of psychological factors that may confound the association, however, the true relationship remained unclear. In this, the first community-based study, we have demonstrated that chronic widespread pain was associated with altered HPA axis function. Specifically, the presence of chronic widespread pain was associated with lower levels of salivary cortisol and higher levels of post-stressor serum cortisol.

    Conclusion



    We have previously shown that psychological status is a strong predictor of the onset of chronic widespread pain [2], although the biological mechanism through which such factors may lead to pain was unclear. The altered HPA function evident in subjects in the present study is one possible mechanism. We propose that the impaired HPA axis tone as shown by the low salivary cortisol measurements indicates a failure to mount an adequate stress response to psychological insult, and that this failure predisposes to the development of chronic widespread pain. However, this model can only be examined in a prospective study. To that end we are following-up those persons in the current study who were 'at risk' of the future development of symptoms to determine whether, among that group of subjects who are psychologically distressed, altered HPA function predicts symptom onset.

    http://arthritis-research.com/content/7/5/R992
  2. davebhoy

    davebhoy New Member

    there seems to be mroe and more research that points to hpa axis probs being the the key or at least a large part of the problem with cfs and fibro.

    noone seems to be coming up with any answers at presnt, though.
  3. elsa

    elsa New Member



    Thanks for posting. I agree that they are connected. Very interesting ......

    Elsa