The 1μg short Synacthen test in chronic fatigue syndrome

Abstract

There were no significant differences in baseline cortisol or cortisol responses between patients and controls. However, responses generally were low, and many subjects' peak responses were prior to the standard 30 minute sampling time., CONCLUSIONS These results do not lend support to the theory that patients with chronic fatigue syndrome have a low adrenal reserve. However, results from studies assessing the HPA axis are proving to be inconsistent. We suggest that many other factors may be contributing to HPA axis alterations in chronic fatigue syndrome, including sleep disturbance, inactivity, altered circadian rhythmicity, illness chronicity, concomitant medication and comorbid psychiatric disturbance. These sources of heterogeneity need to be considered in future studies, and may explain the inconsistent findings to date.

Polymorphisms in Genes Regulating the HPA Axis Associated with Empirically Delineated Classes of Unexplained Chronic Fatigue

“…Scott and colleagues [16] also reported reduced ACTH responses to CRH challenge, but noted reduced cortisol responses, whereas Cleare and colleagues [17] reported normal ACTH responses but attenuated cortisol responses. Tests utilizing ACTH administration demonstrate equally unclear results [15,18,19]. In light of this study, it is possible that genetic variations in POMC and NR3C1 may contribute to the pathophysiology of a subgroup of patients with chronic fatigue, and this heterogeneity may explain the previous inconsistencies in the literature.…”

Stress as a Pathophysiological Factor in Functional Somatic Syndromes

“…However, other studies found no difference in salivary cortisol concentrations between CFS and healthy controls [91,92]. Insight from pharmacological challenge studies testing specific levels of HPA axis regulation indicates enhanced feedback sensitivity [92][93][94][95], increased adrenocortical sensitivity to adrenocorticotropic hormone (ACTH), and a reduced maximal cortisol response compared to normal subjects [81,96], with nonsignificant findings being reported also [97,98]. Clearly, findings point toward relative hypocortisolism in CFS.…”

24-Hour Pituitary and Adrenal Hormone Profiles in Chronic Fatigue Syndrome

“…One explanation for the low ACTH but normal cortisol levels in CFS, hypothesized by Demitrack and colleagues (35), is that blunted ACTH is in part the result of an impaired central nervous system drive inducing a reduction of hypothalamic output of corticotrophin-releasing hormone (CRH) and/or other secretagogues. This consequently leads to reduced ACTH levels and a compensatory upregulation of the adrenal cortex responsivity to ACTH, something previously found by some (36) but not others (37)(38)(39).…”