Salivary cortisol profiles in chronic fatigue syndrome

Evaluating Routine Blood Tests According to Clinical Symptoms and Diagnostic Criteria in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

There is a lack of research regarding blood tests within individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and between patients and healthy controls. We aimed to compare results of routine blood tests between patients and healthy controls. Data from 149 patients diagnosed with ME/CFS based on clinical and psychiatric evaluation as well as on the DePaul Symptom Questionnaire, and data from 264 healthy controls recruited from blood donors were compared. One-way ANCOVA was conducted to examine differences between ME/CFS patients and healthy controls, adjusting for age and gender. Patients had higher sedimentation rate (mean difference: 1.38, 95% CI: 0.045 to 2.714), leukocytes (mean difference: 0.59, 95% CI: 0.248 to 0.932), lymphocytes (mean difference: 0.27, 95% CI: 0.145 to 0.395), neutrophils (mean difference: 0.34, 95% CI: 0.0 89 to 0.591), monocytes (mean difference: 0.34, 95% CI: 0.309 to 0.371), ferritin (mean difference: 28.13, 95% CI: −1.41 to 57.672), vitamin B12 (mean difference: 83.43, 95% CI: 62.89 to 124.211), calcium (mean difference: 0.02, 95% CI: −0.02 to 0.06), alanine transaminase (mean difference: 3.30, 95% CI: −1.37 to -7.971), low-density lipoproteins (mean difference: 0.45, 95% CI: 0.104 to 0.796), and total proteins (mean difference: 1.53, 95% CI: −0.945 to 4.005) than control subjects. The patients had lower potassium levels (mean difference: 0.11, 95% CI: 0.056 to 0.164), creatinine (mean difference: 2.60, 95% CI: 0.126 to 5.074) and creatine kinase (CK) (mean difference: 37.57, 95% CI: −0.282 to 75.422) compared to the healthy controls. Lower CK and creatinine levels may suggest muscle damage and metabolic abnormalities in ME/CFS patients.

Changes in the levels of IL-1β, cortisol and chromogranin A in saliva of subjects with occupational fatigue

Changes in the levels of interleukin-1β (IL-1β), cortisol and chromogranin A (CgA) in saliva of subjects with occupational fatigue were investigated. Doctors in the Emergency Department were selected as research subjects. Saliva was collected before work (after full rest) and after work (≥24 h). Electroencephalogram (EEG) was performed. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of IL-1β, cortisol and CgA in saliva. In order to obtain permission for human specimens, the study was approved by the Ethics Committee of the Affiliated Hospital of Hebei University of Engineering and registered for clinical trials (registration no. ChiC-TR-DCD-14005746). As there were only 4 subjects in this study without fatigue waves in EEG, and the number of these subjects was not sufficient to constitute a control group, the comparison of the contents of IL-1β, cortisol and CgA of all subjects before and after working for 18 h was just a confirmation of the statistical results of 43 cases with fatigue waves in the EEG. According to the results, there was no change in the contents of IL-1β and cortisol in the saliva of subjects with occupational fatigue before and after fatigue, whereas, there was a significant change in the content of CgA before and after fatigue. However, there was no correlation between the content of CgA and fatigue. The results of the present study revealed that IL-1β, cortisol and CgA indicators are not suitable diagnostic markers for occupational fatigue.

CNS findings in chronic fatigue syndrome and a neuropathological case report

Chronic fatigue syndrome (CFS) is characterized as a persistent, debilitating complex disorder of unknown etiology, whereby patients suffer from extreme fatigue, which often presents with symptoms that include chronic pain, depression, weakness, mood disturbances, and neuropsychological impairment. In this mini review and case report, we address central nervous system (CNS) involvement of CFS and present neuropathological autopsy findings from a patient who died with a prior diagnosis of CFS. Among the most remarkable pathological features of the case are focal areas of white matter loss, neurite beading, and neuritic pathology of axons in the white matter with axonal spheroids. Atypical neurons displaying aberrant sprouting processes in response to injury are observed throughout cortical gray and white matter. Abundant amyloid deposits identical to AD plaques with accompanying intracellular granular structures are observed as well. Neurofibrillary tangles are also present in the white matter of the frontal cortex, thalamus and basal ganglia. Taken together, these neuropathological findings warrant further studies into CNS disease associated with CFS.

Chronic Fatigue Syndrome: The Current Status and Future Potentials of Emerging Biomarkers

Chronic fatigue syndrome (CFS) remains an incompletely characterized illness, in part due to controversy regarding its definition, biological basis and diagnosis. Biomarkers are objective measures that may lead to improvements in our understanding of CFS by providing a more coherent and consistent approach to study, diagnosis and treatment of the illness. Such metrics may allow us to distinguish between CFS subtypes - each defined by characteristic biomarkers - currently conflated under the single, heterogeneous condition of CFS. These delineations, in turn, may guide more granular, focused, and targeted treatment strategies based on more precise characterizations of the illness. Here, we review potential CFS biomarkers related to neurological and immunological components of the illness, and discuss how these biomarkers may be used to move the field of CFS forward, emphasizing clinical utility and potential routes of future research.

Unstimulated cortisol secretory activity in everyday life and its relationship with fatigue and chronic fatigue syndrome: a systematic review and subset meta-analysis

The hypothalamic-pituitary-adrenal (HPA) axis is a psychoneuroendocrine regulator of the stress response and immune system, and dysfunctions have been associated with outcomes in several physical health conditions. Its end product, cortisol, is relevant to fatigue due to its role in energy metabolism. The systematic review examined the relationship between different markers of unstimulated salivary cortisol activity in everyday life in chronic fatigue syndrome (CFS) and fatigue assessed in other clinical and general populations. Search terms for the review related to salivary cortisol assessments, everyday life contexts, and fatigue. All eligible studies (n=19) were reviewed narratively in terms of associations between fatigue and assessed cortisol markers, including the cortisol awakening response (CAR), circadian profile (CP) output, and diurnal cortisol slope (DCS). Subset meta-analyses were conducted of case-control CFS studies examining group differences in three cortisol outcomes: CAR output; CAR increase; and CP output. Meta-analyses revealed an attenuation of the CAR increase within CFS compared to controls (d=-.34) but no statistically significant differences between groups for other markers. In the narrative review, total cortisol output (CAR or CP) was rarely associated with fatigue in any population; CAR increase and DCS were most relevant. Outcomes reflecting within-day change in cortisol levels (CAR increase; DCS) may be the most relevant to fatigue experience, and future research in this area should report at least one such marker. Results should be considered with caution due to heterogeneity in one meta-analysis and the small number of studies.

Chronic fatigue syndrome following infections in adolescents

PURPOSE OF REVIEW

To review the recent epidemiology, pathophysiology, and treatment of postinfectious chronic fatigue syndrome (CFS) in adolescents.

RECENT FINDINGS

Thirteen percent of adolescents (mainly women) met the criteria for CFS 6 months following infectious mononucleosis; the figure was 7% at 12 months and 4% at 24 months. Peak work capacity, activity level, orthostatic intolerance, salivary cortisol, and natural killer cell number and function were similar between adolescents with CFS following infectious mononucleosis and recovered controls. Autonomic system, oxygen consumption, peak oxygen pulse, psychological and cytokine network differences were documented between those who recovered and those who did not.

SUMMARY

The prognosis of CFS is better in adolescents than in adults. Activity level, exercise tolerance, and orthostatic testing could not distinguish patients with CFS from adolescents who have recovered from infectious mononucleosis (controls), while certain cytokine network analyses, life stress factors, and autonomic symptoms could.

Meta-analysis and meta-regression of hypothalamic-pituitary-adrenal axis activity in functional somatic disorders

Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is the most investigated biological risk marker in functional somatic disorders (FSDs), such as chronic fatigue syndrome (CFS), fibromyalgia (FM), and irritable bowel syndrome (IBS). Our aim was to assess whether there is an association between basal hypocortisolism and FSD and to identify potential moderators of this association. Meta-analysis on 85 studies revealed that although basal cortisol levels were generally lower in FSD subjects compared to controls, this association did not reach statistical significance (SMD -0.07, 95% CI -0.17 to 0.04, p=0.241). However, when the three FSD were assessed separately, statistically significant basal hypocortisolism was observed in CFS subjects compared to controls (SMD -0.14, 95% CI -0.28 to 0.00, p=0.047), but not in FM or IBS. When all potential moderators were entered into a meta-regression analysis, only type of FSD and female gender were significant independent predictors of basal hypocortisolism. In conclusion, we did not find evidence to consider all three main FSD as hypocortisolemic disorders, as significant reduction in basal cortisol compared to healthy controls was only found in CFS and in females with FM, but not in IBS.

Diffuse noxious inhibitory control is delayed in chronic fatigue syndrome: an experimental study

Deficient endogenous pain inhibition, e.g. Diffuse noxious inhibitory controls (DNIC), or hormonal abnormalities like hypocortisolism, could be responsible for chronic widespread pain in Chronic Fatigue Syndrome (CFS). Thirty-one CFS-patients with chronic pain and 31 healthy controls were subjected to spatial summation of thermal noxious stimuli by gradual immersion (ascending or descending) of the arm in warm water (46 degrees C). They rated pain intensity every 15s. Every immersion took 2 min, alternated with 5 min rest. Before and after immersion, salivary cortisol was assessed. Overall pain ratings were higher in CFS-patients, but the evolution was not different between patients and controls, during both ascending and descending immersion. Pain intensity and immersed surface were only correlated during the descending session in both patients (r=.334) and controls (r=.346). When comparing the first and the last 15s of every emersion, it was found that pain inhibition starts slower for CFS-patients in comparison to healthy subjects. Both pre- or post-values and cortisol response did not differ between controls and patients. The drop in cortisol was significantly correlated to pain intensity in CFS (r between .357 and .402). In addition to the hyperalgesia in CFS, DNIC react slower to spatial summation of thermal noxious stimuli. We found no evidence for hypocortisolism in CFS, and the cortisol response to nociception was not different in CFS compared to healthy subjects. In conclusion, delayed pain inhibition may play a role in chronic widespread pain in CFS but further research is required.

Glucocorticoid sensitivity of immune cells in severely fatigued adolescent girls: a longitudinal study

Fatigue during adolescence is associated with somatic and psychological complaints that resemble the pattern of symptoms described for chronic fatigue syndrome (CFS). Studies in CFS and other stress-related syndromes suggested a dysfunction of the interactions between the hypothalamic-pituitary-adrenal axis (HPA-axis) and the immune system, i.e. a changed glucocorticoid (GC) receptor sensitivity of immune cells, to exist. Here we investigated whether severely fatigued girls from a healthy population have altered cortisol production and immune cell sensitivity for the synthetic GC, dexamethasone (DEX). In a longitudinal design, we examined ex vivo DEX sensitivity of monocytes and of T-cell mitogen-induced responses of severely fatigued (N=65) and non-fatigued girls (N=60). Fatigued girls reported more severe comorbid complaints than non-fatigued participants across three measurements during 1 year (T1: spring, T2: autumn, T3: spring) and had higher plasma cortisol levels throughout the study. DEX sensitivity of T-cell mitogen-induced responses showed seasonal variation with increased sensitivity in autumn compared to spring. No systematic variation of monocyte glucocorticoid receptor (GR) sensitivity was observed. Significant rank correlations of DEX sensitivity of T-cell mitogen-induced responses between the three assessments during the year suggest a stable trait of immune function. Groups did not differ in DEX sensitivity on any of the read outs. However, in a persistently fatigued subgroup, sensitivity to DEX was significantly reduced on the level of interferon (IFN)-gamma production. These results show that although fatigued participants had severe (comorbid) complaints, only in the case when symptoms persisted, altered GC sensitivity of immune cells was observed.

Chronic fatigue syndrome: a systematic review

OBJECTIVE

A systematic review of the literature about chronic fatigue syndrome (CFS).

METHODS

A search of the Medline database (via Ovid and PubMed) with the key words chronic fatigue syndrome, diagnosis, classification, epidemiology, etiology, physiopathology, metabolism, microbiology, immunology, virology, psychology, drug therapy, rehabilitation, and therapy. The reference lists of each article were examined for additional related articles.

RESULTS

CFS was defined in 1988 by the US Centes for Disease Control and Prevention. The prevalence of chronic fatigue syndrome has ranged from 0.2% to 0.7% in the general population. In 1994, the definition of CFS was revised by Fukuda et al. Despite various research in several topics (e.g. infection, immune systems, neuroendocrinology, autonomic activity, neuromuscular involvement), the pathophysiology remains unknown.

CONCLUSION

CFS, with its various major clinical and functional impacts, should be associated with a "biopsychosocial model". Progressive muscular rehabilitation, combined with behavioral and cognitive treatment, is an essential part of therapy.

The morning salivary cortisol response in burnout

OBJECTIVES

The aim of the present study was to examine the free salivary cortisol response to awakening in men and women reporting low, moderate, and high levels of burnout.

METHODS

Twenty-two patients on sick leave due to burnout were compared with 22 working participants with low and 20 working participants with intermediate scores on the Shirom-Melamed Burnout Questionnaire (SMBQ), with regard to the free salivary cortisol response to awakening. Saliva samples were collected upon awakening and at +15, +30, and +60 min thereafter.

RESULTS

Female burnout patients had higher cortisol levels than did the females with low burnout at awakening and at +15, +30, and +60 min after awakening. They also had a greater area under the curve (AUC) for salivary cortisol than did the female participants with low burnout. Male participants with moderate levels of burnout had higher cortisol levels at +60 min after awakening compared with males with low burnout.

CONCLUSIONS

The results of the present study indicate a dysregulation in hypothalamic-pituitary-adrenocortical axis (HPA axis) activity, characterised by elevated morning salivary cortisol levels, among female burnout patients. Among males, increased cortisol levels were observed among participants with moderate levels of burnout, but not among patients or healthy controls.

Diurnal patterns of salivary cortisol and cortisone output in chronic fatigue syndrome

BACKGROUND

The aim of the present study was to obtain a naturalistic measure of diurnal hypothalamic-pituitary-adrenal (HPA) axis output in CFS patients unaffected by medication or comorbid psychiatric disorder likely to influence the axis.

METHOD

Cortisol and cortisone levels were measured in saliva samples collected from 0600 h to 2100 h at 3-h intervals in CFS patients and healthy controls.

RESULTS

Mean cortisol and cortisone concentrations were significantly lower in patients than controls across the whole day, as were levels at each individual time point except 2100 h. Cosinor analysis showed a significant diurnal rhythm of cortisol and cortisone that was not phase-shifted in CFS compared to controls. However, there was a lower rhythm-adjusted mean and a lower amplitude in CFS patients. The cortisol/cortisone ratio showed no diurnal rhythm and did not differ between CFS subjects and controls.

LIMITATIONS

The sample size was relatively small, and drawn from specialist referral patients who had been ill for some time; generalisation of these results to other populations is therefore unwarranted.

CONCLUSION

The main findings of this study are to provide further evidence for reduced basal HPA axis function in at least some patients with CFS and to show for the first time that salivary cortisone is also reduced in CFS and has a diurnal rhythm similar to that of cortisol. We have also demonstrated that the cortisol/cortisone ratio remains unchanged in CFS, suggesting that increased conversion of cortisol to cortisone cannot account for the observed lowering of salivary cortisol.

24-hour pituitary and adrenal hormone profiles in chronic fatigue syndrome

OBJECTIVES

Disturbances of neuroendocrine function, particularly the hypothalamo-pituitary-adrenal (HPA) axis, have been implicated in the pathophysiology of chronic fatigue syndrome (CFS). However, few studies have attempted to measure blood levels of pituitary or adrenal hormones across a whole 24-hour period in CFS, and those that did so have used infrequent sampling periods. Our aim was to assess 24-hour pituitary and adrenal function using frequent blood sampling.

METHODS

We recruited 15 medication-free patients with CFS without comorbid psychiatric disorder and 10 healthy control subjects. Blood samples were collected over 24 hours and assayed for cortisol, corticotropin (ACTH), growth hormone (GH), and prolactin (PRL) levels on an hourly basis during daytime hours (10 am to 10 pm) and every 15 minutes thereafter (10 pm to 10 am).

RESULTS

Repeated-measures analyses of variance were undertaken using hormone levels averaged over 2-hour blocks to smooth curves by reducing the influence of sample timing relative to secretory burst. For ACTH, there was both a main effect of group, suggesting reduced mean ACTH secretion in patients with CFS over the whole monitoring period, and a group-by-time interaction, suggesting a differential pattern of ACTH release. Post hoc analysis showed reduced ACTH levels in CFS during the 8 am to 10 am period. In contrast, there were no significant abnormalities in the levels of cortisol, GH, and PRL in patients with CFS over the full cycle compared with control subjects. Cosinor analysis found no differences in the cortisol circadian rhythm parameters, but the ACTH rhythm did differ, patients with CFS showing an earlier acrophase.

CONCLUSIONS

Patients with CFS demonstrated subtle alterations in HPA axis activity characterized by reduced ACTH over a full circadian cycle and reduced levels during the usual morning physiological peak ACTH secretion. This provides further evidence of subtle dysregulation of the HPA axis in CFS. Whether this dysregulation is a primary feature of the illness or instead represents a biologic effect secondary to having the illness itself remains unclear.

Salivary cortisol as a predictor of postoperative fatigue

OBJECTIVE

Some patients with chronic fatigue syndrome (CFS) exhibit low basal cortisol levels, but it is not known whether low cortisol is a cause of CFS, predates the onset of CFS symptoms, or is an epiphenomenon caused by the behavioral changes typical of CFS. Because elective surgery is one of the few predictable risk factors for chronic fatigue, in this study, we followed a cohort of surgery patients from before to 6 months after their operation to test these theories.

METHOD

One hundred sixty-one patients completed fatigue questionnaires and provided salivary cortisol samples before undergoing an elective inpatient surgical procedure, and then 2 days, 3 weeks, and 6 months afterward.

RESULTS

Controlling for relevant demographic and surgical variables and for preoperative fatigue, low preoperative cortisol did not predict postoperative fatigue severity on any occasion (p > .05). Similarly, there was no correlation between low postoperative cortisol and postoperative fatigue severity at 3 weeks or 6 months (p > .05). Although 16 patients met our case definition for "chronic fatigue" at the 6-month follow up, low preoperative and low postoperative cortisol did not significantly predict fatigue caseness (p > .05).

CONCLUSIONS

Any association between chronic fatigue and low cortisol would seem to develop after the onset of fatigue symptoms. Low cortisol is therefore unlikely to be the primary cause of chronic fatigue states.

Normal opioid tone and hypothalamic-pituitary-adrenal axis function in chronic fatigue syndrome despite marked functional impairment

OBJECTIVE

To determine whether the functional impairment seen in chronic fatigue syndrome (CFS) is associated with reduced levels of central opioids and/or deficiency of the hypothalamic-pituitary-adrenal (HPA) axis.

DESIGN

Single-blinded case-control study measuring functional and psychological status, basal hormonal parameters and ACTH/cortisol response to naloxone and ovine corticotrophin-releasing hormone (oCRH) vs. placebo in people with CFS and healthy controls.

PATIENTS

Twelve people with CFS and 11 age-matched controls.

MEASUREMENTS

Hormonal parameters: basal levels of 09:00 h plasma cortisol, dehydroepiandrosterone sulfate (DHEAS) and IGF-1. 24-h urinary free cortisol. Plasma ACTH and cortisol response to naloxone 125 microg/kg, oCRH 1 microg/kg and placebo (normal saline). Psychological parameters: SF-36, Hamilton Depression Score, Hospital Anxiety and Depression Scale and Fatigue Scale.

RESULTS

There were highly significant differences between the CFS subjects and the controls with respect to the measures of fatigue and physical functioning. However, there were no differences in basal levels of 09:00 h cortisol (367 +/- 37 vs. 331 +/- 39 nmol/l, P = 0.51), DHEAS (4.2 +/- 0.6 vs. 4.0 +/- 0.5 micromol/l, P = 0.81), 24-h urinary free cortisol (182 +/- 27 vs. 178 +/- 21 nmol/24 h, P = 0.91) or IGF-1 (145 +/- 19 vs. 130 +/- 11 microg/l, P = 0.52) between the CFS group and controls, respectively. There was also no difference between the groups with respect to the ACTH and cortisol response to either oCRH or naloxone.

CONCLUSIONS

Our data do not support an aetiological role for deficiency in central opioids or the HPA axis in the symptoms of CFS.

Hypothalamic-pituitary-gonadal axis hormones and cortisol in both menstrual phases of women with chronic fatigue syndrome and effect of depressive mood on these hormones

BACKGROUND

Chronic fatigue syndrome (CFS) is a disease which defined as medically unexplained, disabling fatigue of 6 months or more duration and often accompanied by several of a long list of physical complaints. We aimed to investigate abnormalities of hypothalamic-pituitary-gonadal (HPG) axis hormones and cortisol concentrations in premenopausal women with CFS and find out effects of depression rate on these hormones.

METHODS

We examined follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone and cortisol concentrations in 43 premenopausal women (mean age: 32.86 +/- 7.11) with CFS and compared matched 35 healthy controls (mean age: 31.14 +/- 6.19). Patients were divided according to menstrual cycle phases (follicular and luteal) and compared with matched phase controls. Depression rate was assessed by Beck Depression Inventory (BDI), and patients with high BDI scores were compared to patients with low BDI scores.

RESULTS

There were no significant differences in FSH, LH, estradiol and progesterone levels in both of menstrual phases of patients versus controls. Cortisol levels were significantly lower in patients compared to controls. There were no significant differences in all hormone levels in patients with high depression scores versus patients with low depression scores.

CONCLUSION

In spite of high depression rate, low cortisol concentration and normal HPG axis hormones of both menstrual phases are detected in premenopausal women with CFS. There is no differentiation between patients with high and low depression rate in all hormone levels. Depression condition of CFS may be different from classical depression and evaluation of HPG and HPA axis should be performed for understanding of pathophysiology of CFS and planning of treatment.

Cortisol and hypothalamic-pituitary-gonadal axis hormones in follicular-phase women with fibromyalgia and chronic fatigue syndrome and effect of depressive symptoms on these hormones

We investigated abnormalities of the hypothalamic-pituitary-gonadal axis and cortisol concentrations in women with fibromyalgia and chronic fatigue syndrome (CFS) who were in the follicular phase of their menstrual cycle, and whether their scores for depressive symptoms were related to levels of these hormones. A total of 176 subjects participated - 46 healthy volunteers, 68 patients with fibromyalgia, and 62 patients with CFS. We examined concentrations of follicle-stimulating hormone, luteinizing hormone (LH), estradiol, progesterone, prolactin, and cortisol. Depressive symptoms were assessed using the Beck Depression Inventory (BDI). Cortisol levels were significantly lower in patients with fibromyalgia or CFS than in healthy controls (P < 0.05); there were no significant differences in other hormone levels between the three groups. Fibromyalgia patients with high BDI scores had significantly lower cortisol levels than controls (P < 0.05), and so did CFS patients, regardless of their BDI scores (P < 0.05). Among patients without depressive symptoms, cortisol levels were lower in CFS than in fibromyalgia (P < 0.05). Our study suggests that in spite of low morning cortisol concentrations, the only abnormalities in hypothalamic-pituitary-gonadal axis hormones among follicular-phase women with fibromyalgia or CFS are those of LH levels in fibromyalgia patients with a low BDI score. Depression may lower cortisol and LH levels, or, alternatively, low morning cortisol may be a biological factor that contributes to depressive symptoms in fibromyalgia. These parameters therefore must be taken into account in future investigations.

Glucocorticoids and glucocorticoid receptors: mediators of fatigue?

Fatigue is a common problem; when chronic and disabling, subjects can be categorized as having chronic fatigue syndrome (CFS). Whilst it is most likely a multifactorial condition of biopsychosocial origin, the nature of the pathophysiological component remains unclear. There has been a wealth of interest in the possible hypothalamo-pituitary-adrenal (HPA) axis dysfunction in CFS, and whether such changes may mediate fatigue. On balance, there appears to be reduced cortisol output in a proportion of patients, together with heightened negative feedback and glucocorticoid receptor function. There is evidence for impaired adrenocorticotropic hormone (ACTH) and cortisol responses to a variety of challenges. However, there is no evidence for a specific or uniform dysfunction of the HPA axis. Evidence that these changes may be related to symptom production comes from randomized controlled trials of glucocorticoid replacement therapy, which have shown improvements in fatigue and disability. Given the many factors that may impinge on the HPA axis in CFS, such as inactivity, sleep disturbance, psychiatric comorbidity, medication and ongoing stress, it seems likely that there is not a single or specific change to the HPA axis in CFS and that the observed HPA axis disturbances are of multifactorial etiology. This is further supported by a comparison of neuroendocrine findings in other conditions in which fatigue is prominent, showing both similarities and differences with the pattern in CFS.

The neuroendocrinology of chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a common and disabling problem; although most likely of biopsychosocial origin, the nature of the pathophysiological components remains unclear. There has been a wealth of interest in the endocrinology of this condition, which will be reviewed in this article. Most studied has been the hypothalamic-pituitary-adrenal (HPA) axis; although the quality of many studies is poor, the overall balance of evidence points to reduced cortisol output in at least some patients, with some evidence that this is linked to symptom production or persistence. There is evidence for heightened negative feedback and glucocorticoid receptor function and for impaired ACTH and cortisol responses to a variety of challenges. However, there is no evidence for a specific or uniform dysfunction of the HPA axis. Given the many factors that may impinge on the HPA axis in CFS, such as inactivity, sleep disturbance, psychiatric comorbidity, medication, and ongoing stress, it seems likely that HPA axis disturbance is heterogeneous and of multifactorial etiology in CFS. Studies assessing GH, dehydroepiandrostenedione and its sulfate, melatonin, leptin, and neuroendocrine-monoamine interactions are also reviewed. There is some evidence from these studies to suggest alterations of dehydroepiandrostenedione sulfate function and abnormal serotonin function in CFS, but whether these changes are of functional importance remains unclear. To obtain a clearer assessment of the etiological and pathophysiological relevance of endocrine changes in CFS, it is suggested that more prospective cohort studies be undertaken in groups at high risk for CFS, that patients with CFS are followed up into recovery, and that multidimensional assessments are undertaken to unravel the influence of the various confounding factors on the observed endocrine changes in CFS.

Low-dose dexamethasone suppression test in chronic fatigue syndrome and health

OBJECTIVE

Subtle dysregulations of the hypothalamus-pituitary-adrenal axis in chronic fatigue syndrome have been described. The aim of this study was to examine the negative feedback regulations of the hypothalamus-pituitary-adrenal axis in chronic fatigue syndrome.

METHODS

In 21 patients with chronic fatigue syndrome and 21 healthy control subjects, awakening and circadian salivary free cortisol profiles were assessed over 2 consecutive days and compared with awakening and circadian salivary free cortisol profiles after administration of 0.5 mg of dexamethasone at 11:00 PM the previous day.

RESULTS

Patients with chronic fatigue syndrome had normal salivary free cortisol profiles but showed enhanced and prolonged suppression of salivary free cortisol after the administration of 0.5 mg of dexamethasone in comparison to the control subjects.

CONCLUSIONS

Enhanced negative feedback of the hypothalamus-pituitary-adrenal axis could be a plausible explanation for the previously described alterations in hypothalamus-pituitary-adrenal axis functioning in chronic fatigue syndrome. Because similar changes have been described in stress-related disorders, a putative role of stress in the pathogenesis of the enhanced feedback is possible.

Hypothalamo-pituitary-adrenal axis dysfunction in chronic fatigue syndrome, and the effects of low-dose hydrocortisone therapy

These neuroendocrine studies were part of a series of studies testing the hypotheses that 1) there may be reduced activity of the hypothalamic-pituitary-adrenal axis in chronic fatigue syndrome and 2) low-dose augmentation with hydrocortisone therapy would improve the core symptoms. We measured ACTH and cortisol responses to human CRH, the insulin stress test, and D-fenfluramine in 37 medication-free patients with CDC-defined chronic fatigue syndrome but no comorbid psychiatric disorders and 28 healthy controls. We also measured 24-h urinary free cortisol in both groups. All patients (n = 37) had a pituitary challenge test (human CRH) and a hypothalamic challenge test [either the insulin stress test (n = 16) or D-fenfluramine (n = 21)]. Baseline cortisol concentrations were significantly raised in the chronic fatigue syndrome group for the human CRH test only. Baseline ACTH concentrations did not differ between groups for any test. ACTH responses to human CRH, the insulin stress test, and D- fenfluramine were similar for patient and control groups. Cortisol responses to the insulin stress test did not differ between groups, but there was a trend for cortisol responses both to human CRH and D-fenfluramine to be lower in the chronic fatigue syndrome group. These differences were significant when ACTH responses were controlled. Urinary free cortisol levels were lower in the chronic fatigue syndrome group compared with the healthy group. These results indicate that ACTH responses to pituitary and hypothalamic challenges are intact in chronic fatigue syndrome and do not support previous findings of reduced central responses in hypothalamic-pituitary-adrenal axis function or the hypothesis of abnormal CRH secretion in chronic fatigue syndrome. These data further suggest that the hypocortisolism found in chronic fatigue syndrome may be secondary to reduced adrenal gland output. Thirty-two patients were treated with a low-dose hydrocortisone regime in a double-blind, placebo-controlled cross-over design, with 28 days on each treatment. They underwent repeated 24-h urinary free cortisol collections, a human CRH test, and an insulin stress test after both active and placebo arms of treatment. Looking at all subjects, 24-h urinary free cortisol was higher after active compared with placebo treatments, but 0900-h cortisol levels and the ACTH and cortisol responses to human CRH and the insulin stress test did not differ. However, a differential effect was seen in those patients who responded to active treatment (defined as a reduction in fatigue score to the median population level or less). In this group, there was a significant increase in the cortisol response to human CRH, which reversed the previously observed blunted responses seen in these patients. We conclude that the improvement in fatigue seen in some patients with chronic fatigue syndrome during hydrocortisone treatment is accompanied by a reversal of the blunted cortisol responses to human CRH.

Psychoneuroendocrinological contributions to the etiology of depression, posttraumatic stress disorder, and stress-related bodily disorders: the role of the hypothalamus-pituitary-adrenal axis

Following the assumption that stressors play an important part in the etiology and maintenance of psychiatric disorders, it is necessary to evaluate parameters reflecting stress-related physiological reactions. Results from these examinations may help to deepen the insight into the etiology of psychiatric disorders and to elucidate diagnostic uncertainties. One of the best-known stress-related endocrine reactions is the hormonal release of the hypothalamic-pituitary-adrenal (HPA) axis. Dysregulations of this axis are associated with several psychiatric disorders. Profound hyperactivity of the HPA-axis has been found in melancholic depression, alcoholism, and eating disorders. In contrast, posttraumatic stress disorder, stress-related bodily disorders like idiopathic pain syndromes, and chronic fatigue syndrome seem to be associated with diminished HPA activity (lowered activity of the adrenal gland). Hypotheses referring to (a) the psychophysiological meaning and (b) the development of these alterations are discussed.

Chronic fatigue syndrome: an update

The chronic fatigue syndrome is characterised by a fatigue that is disproportionate to the intensity of effort that is undertaken, has persisted for 6 months or longer, and has no obvious cause. Unless there has been a long period of patient- or physician-imposed inactivity, objective data may show little reduction in muscle strength or peak aerobic power, but the affected individual avoids heavy activity. The study of aetiology and treatment has been hampered by the low disease prevalence (probably <0.1% of the general population), and (until recently) by a lack of clear and standardised diagnostic criteria. It is unclear how far the aetiology is similar for athletes and nonathletes. It appears that in top competitors, overtraining and/or a negative energy balance can be precipitating factors. A wide variety of other possible causes and/or precipitating factors have been cited in the general population, including psychological stress, disorders of personality and affect, dysfunction of the hypothalamic-pituitary-adrenal axis, hormonal imbalance, nutritional deficits, immune suppression or activation and chronic infection. However, none of these factors have been observed consistently. The prognosis is poor; often disability and impairment of athletic performance are prolonged. Prevention of overtraining by careful monitoring seems the most effective approach in athletes. In those where the condition is established, treatment should aim at breaking the vicious cycle of effort avoidance, deterioration in physical condition and an increase in fatigue through a combination of encouragement and a progressive exercise programme.

The 1microg short Synacthen test in chronic fatigue syndrome

OBJECTIVE

Many studies suggest mild hypocortisolism in chronic fatigue syndrome (CFS), usually assumed to be due to reduced suprahypothalamic drive to the hypothalamo-pituitary-adrenal (HPA) axis. We wished to explore further the state of the HPA axis in CFS using the 1 microg low dose short Synacthen test.

DESIGN

Subjects received an intravenous bolus of 1 microg Synacthen; samples for cortisol estimation were taken at baseline and 2, 10, 20, 30, 40 and 60 minutes after injection.

PATIENTS

We tested 20 subjects suffering from CFS according to the criteria of the Center for Diseases Control without psychiatric comorbidity and 20 matched healthy controls. All subjects were drug free for at least 1 month.

MEASUREMENTS

We calculated the cortisol responses to the test as the maximum cortisol attained, the incremental rise in cortisol over baseline (Deltavalue) and as the integrated area under the curve.

RESULTS

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.

A review of fatigue in people with HIV infection

Fatigue is often cited by clinicians as a debilitating symptom suffered by the many who are infected with HIV. This article provides a review of HIV-related fatigue, including research on possible physiological causes such as anemia, CD4 count, impaired liver function, impaired thyroid function, and cortisol abnormalities. Psychological causes of fatigue, particularly depression, are reviewed as well. Measurement issues, such as the use of inappropriate tools, the problem of measuring the presence or absence of fatigue, and the use of tools developed for other groups of patients, are reviewed. The need for a comprehensive fatigue tool that is appropriate for people with HIV is discussed. Current treatment research, including thyroid replacement, hyperbaric oxygen, and dextroamphetamine, is presented. Finally, the implications for further research, including the need for qualitative studies to learn more about the phenomenon, develop an instrument to measure fatigue, and examine variables together to get a complete picture of this complex concept, are reviewed.

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome

Fibromyalgia was almost completely absent from an urban affluent population compared with poor urban and rural communities. Seventeen percent of Gulf War veterans with soft tissue syndromes had fibromyalgia, a much higher rate than was seen in previous studies of rheumatic disease in the military population. A state of central hyperexcitability in the nociceptive system was reported in fibromyalgia. Altered functioning of the stress-response system has been further documented in fibromyalgia and chronic fatigue syndrome. Administration of growth hormone to patients with fibromyalgia who have low levels of insulin-like growth factor 1 resulted in improvement in their symptoms and tenderness. An association between chronic fatigue syndrome and initial infections was demonstrated. A correlation between particular immunologic abnormalities and measures of disease severity was documented in chronic fatigue syndrome. Concomitant fibromyalgia in other rheumatic diseases was a major contributor to poor quality of life. A favorable outcome of fibromyalgia in children was reported; the majority of patients improved over 2 to 3 years of follow-up. Treatment of patients with fibromyalgia continues to be of limited success.

Chronic fatigue syndrome and fibromyalgia. Dilemmas in diagnosis and clinical management

There has been a resurgence of interest in recent years in both chronic fatigue syndrome and fibromyalgia. These perplexing and common clinical conditions are a source of significant patient morbidity and frame one of the more enduring dilemmas of contemporary Western medical thought, namely the ambiguous interface between mind and body. In this article, the current definitions are reviewed, and a framework for an emerging psychobiological model of these syndromes is presented. These issues are synthesized into a pragmatic approach to clinical management.