HYPOTHALAMIC-PITUITARY-ADRENAL AXIS PERTURBATIONS IN PATIENTS WITH FIBROMYALGIA

Objective. To examine basal and stimulated hypothalamic-pituitary-adre nal (HPA) axis and related hormone levels, including adrenocorticotrop in (ACTH), cortisol, arginine vasopressin (AVP), and neuropeptide Y (N PY), in patients with fibromyalgia (FM). Methods. Basal and ovine cort icotropin-releasing hormone (oCRH)-stimulated HPA axis function were a ssessed in 12 patients with FM and in age- and sex-matched normal subj ects. Basal plasma AVP levels and AVP release after postural change we re assessed, and plasma NPY levels were measured in the same samples. Results. Patients with FM had low 24-hour urinary free cortisol, but n ormal peak and elevated trough plasma cortisol levels, compared with n ormal subjects. The net integrated ACTH response to oCRH in FM was not significantly different from that in normal subjects, but tended towa rd an exaggerated response. There was a significant decrease in net in tegrated cortisol response to oCRH in FM patients, indicating adrenal hyporesponsiveness. AVP levels were not significantly different betwee n FM patients and control subjects, but variability was greater among the FM patients. Plasma NPY levels were significantly lower in FM pati ents than in normal subjects. Conclusion. These data support the view that HPA axis function is perturbed in patients with FM. Further study is required to ascertain the cause of HPA axis perturbations and thei r relationship to symptoms in patients with FM.