Category: Endocrine System

Blunted adrenocorticotropin and cortisol responses to corticotropin-releasing hormone stimulation in chronic fatigue syndrome

Abstract:

Hypofunctioning of the pituitary-adrenal axis has been suggested as the pathophysiological basis for chronic fatigue syndrome (CFS). Blunted adrenocorticotropin (ACTH) responses but normal cortisol responses to exogenous corticotropin-releasing hormone (CRH), the main regulator of this axis, have been previously demonstrated in CFS patients, some of whom had a comorbid psychiatric disorder. We wished to re-examine CRH activation of this axis in CFS patients free from concurrent psychiatric illness.

A sample of 14 patients with CDC-diagnosed CFS were compared with 14 healthy volunteers. ACTH and cortisol responses were measured following the administration of 100 microg ovine CRH. Basal ACTH and cortisol values did not differ between the two groups. The release of ACTH was significantly attenuated in the CFS group (P < 0.005), as was the release of cortisol (P < 0.05).

The blunted response of ACTH to exogenous CRH stimulation may be due to an abnormality in CRH levels with a resultant alteration in pituitary CRH receptor sensitivity, or it may reflect a dysregulation of vasopressin or other factors involved in HPA regulation. A diminished output of neurotrophic ACTH, causing a reduced adrenocortical secretory reserve, inadequately compensated for by adrenoceptor upregulation, may explain the reduced cortisol production demonstrated in this study.

 

Source: Scott LV, Medbak S, Dinan TG. Blunted adrenocorticotropin and cortisol responses to corticotropin-releasing hormone stimulation in chronic fatigue syndrome. Acta Psychiatr Scand. 1998 Jun;97(6):450-7. http://www.ncbi.nlm.nih.gov/pubmed/9669518

 

Evidence for and pathophysiologic implications of hypothalamic-pituitary-adrenal axis dysregulation in fibromyalgia and chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is characterized by profound fatigue and an array of diffuse somatic symptoms.

Our group has established that impaired activation of the hypothalamic-pituitary-adrenal (HPA) axis is an essential neuroendocrine feature of this condition. The relevance of this finding to the pathophysiology of CFS is supported by the observation that the onset and course of this illness is excerbated by physical and emotional stressors. It is also notable that this HPA dysregulation differs from that seen in melancholic depression, but shares features with other clinical syndromes (e.g., fibromyalgia).

How the HPA axis dysfunction develops is unclear, though recent work suggests disturbances in serotonergic neurotransmission and alterations in the activity of AVP, an important co-secretagogue that, along with CRH, influences HPA axis function.

In order to provide a more refined view of the nature of the HPA disturbance in patients with CFS, we have studied the detailed, pulsatile characteristics of the HPA axis in a group of patients meeting the 1994 CDC case criteria for CFS. Results of that work are consistent with the view that patients with CFS have a reduction of HPA axis activity due, in part, to impaired central nervous system drive. These observations provide an important clue to the development of more effective treatment to this disabling condition.

 

Source: Demitrack MA, Crofford LJ. Evidence for and pathophysiologic implications of hypothalamic-pituitary-adrenal axis dysregulation in fibromyalgia and chronic fatigue syndrome. Ann N Y Acad Sci. 1998 May 1;840:684-97. http://www.ncbi.nlm.nih.gov/pubmed/9629295

 

The role of delayed orthostatic hypotension in the pathogenesis of chronic fatigue

Abstract:

Past studies have shown that severe fatigue was the presenting symptom in six of seven patients with delayed orthostatic hypotension and that tilt table-induced hypotension was found in 22 of 23 patients with the chronic fatigue syndrome. We have determined the prevalence of fatigue, volunteered in response to a nonspecific pre-examination questionnaire used in 431 patients, each subsequently diagnosed as having one of eight neurological or endocrine disorders.

The results show that fatigue is a very common symptom in patients with delayed orthostatic hypotension (n = 21), as well as both primary (n = 30) and secondary (n = 106) hypocortisolism: 70-83% in all groups. In contrast, fatigue was an uncommon complaint in patients with multiple system atrophy (MSA) (n = 30), pituitary disorders without hypocortisolism (n = 106) or idiopathic hirsutism (n = 96): 7-33% in all groups, and was intermediate in prevalence in patients with acute hyperadrenergic orthostatic hypotension (n = 32): 41%.

It is concluded that fatigue commonly results from delayed orthostatic hypotension and all forms of hypocortisolism but is less common in patients with acute orthostatic hypotension, both idiopathic and due to MSA, which more commonly present with lightheadedness or syncope.

 

Source: Streeten DH, Anderson GH Jr. The role of delayed orthostatic hypotension in the pathogenesis of chronic fatigue. Clin Auton Res. 1998 Apr;8(2):119-24. http://www.ncbi.nlm.nih.gov/pubmed/9613802

 

Naloxone-mediated activation of the hypothalamic-pituitary-adrenal axis in chronic fatigue syndrome

Abstract:

BACKGROUND: Opioidergic pathways have an inhibitory regulatory influence on the hypothalamic-pituitary-adrenal axis (HPA) in man. Previous studies have suggested impairment of pituitary-adrenal activation in chronic fatigue syndrome (CFS). We, therefore, decided to investigate the extent of opioid inhibition of HPA activity in CFS as a possible explanation for the reputed HPA hypofunctioning in patients with CFS.

METHOD: Thirteen patients with CFS, diagnosed according to CDC criteria, were compared with thirteen healthy subjects. Adrenocorticotropin (ACTH) and cortisol (CORT) responses were measured following the administration of the opiate antagonist naloxone.

RESULTS: Baseline ACTH and cortisol levels did not differ between the two groups. The release of ACTH (but not cortisol) was significantly blunted in the CFS subjects compared with controls.

CONCLUSIONS: Naloxone mediated activation of the HPA is attenuated in CFS. Excessive opioid inhibition of the HPA is thus an unlikely explanation for the HPA dysregulation in this disorder.

 

Source: Scott LV, Burnett F, Medbak S, Dinan TG. Naloxone-mediated activation of the hypothalamic-pituitary-adrenal axis in chronic fatigue syndrome. Psychol Med. 1998 Mar;28(2):285-93. http://www.ncbi.nlm.nih.gov/pubmed/9572086

 

Basal activity of the hypothalamic-pituitary-adrenal axis in patients with the chronic fatigue syndrome (neurasthenia)

Abstract:

BACKGROUND: Impairments in both basal activity and activation of the hypothalamic-pituitary- adrenal axis (HPA) have been reported in chronic fatigue syndrome (CFS; neurasthenia). We sought to replicate these findings and examined basal activity of the HPA in a carefully selected sample of patients with CFS.

METHODS: Basal activity of the HPA was assessed using salivary and urinary cortisol collection over a 24-hour period in 22 (12 male; 10 female) patients meeting criteria for CFS and appropriate controls.

RESULTS: Salivary and urinary cortisol measures did not differ between CFS patients and controls.

CONCLUSIONS: Basal activity of the HPA was not reduced in CFS patients. Reasons for the failure to replicate previous findings are discussed.

 

Source: Young AH, Sharpe M, Clements A, Dowling B, Hawton KE, Cowen PJ. Basal activity of the hypothalamic-pituitary-adrenal axis in patients with the chronic fatigue syndrome (neurasthenia). Biol Psychiatry. 1998 Feb 1;43(3):236-7. http://www.ncbi.nlm.nih.gov/pubmed/9494707

 

A comparison of salivary cortisol in chronic fatigue syndrome, community depression and healthy controls

Abstract:

BACKGROUND: Previous studies reporting cortisol hyposecretion in chronic fatigue syndrome may have been confounded by venepuncture, fasting and hospitalisation.

METHODS: Morning and evening salivary cortisol were obtained on consecutive days in the first 3 days of the menstrual cycle and compared in three samples of women taking no medication and matched for age: 14 patients with chronic fatigue syndrome, 26 community cases of ICD-10 current depressive episodes and 131 healthy community controls.

RESULTS: The mean evening cortisol was significantly lower in the chronic fatigue syndrome patients compared to controls with depression (P = 0.02) and healthy controls (P = 0.005). Chronic fatigue syndrome patients without psychiatric disorder had significantly lower morning salivary cortisols compared to controls (P = 0.009).

CONCLUSION: Chronic fatigue syndrome patients display cortisol hyposecretion in saliva as well as plasma compared to patients with depression and healthy controls.

LIMITATIONS: Small samples of female patients with cortisol estimated at only two time points in the day. Cortisol secretion may be secondary to other neurotransmitter abnormalities or other physiological or lifestyle factors in chronic fatigue syndrome patients.

CLINICAL RELEVANCE: Chronic fatigue syndrome is biochemically distinct from community depression.

 

Source: Strickland P, Morriss R, Wearden A, Deakin B. A comparison of salivary cortisol in chronic fatigue syndrome, community depression and healthy controls. J Affect Disord. 1998 Jan;47(1-3):191-4. http://www.ncbi.nlm.nih.gov/pubmed/9476760

 

Urinary free cortisol excretion in chronic fatigue syndrome, major depression and in healthy volunteers

Abstract:

Urinary free cortisol excretion (UFC) was compared in 21 patients with chronic fatigue syndrome (CFS), in 10 melancholic depressives and in 15 healthy controls.

Patients with depression had UFC values which were significantly higher than healthy comparison subjects, whereas UFC excretion of CFS patients was significantly lower than the comparison group.

These findings are in keeping with currently held hypotheses of hyperactivity and hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis in depression and chronic fatigue syndrome respectively. Five of the 21 CFS patients had a co-morbid depressive illness. This sub-group retained the profile of UFC excretion of those with CFS alone, suggesting a different pathophysiological basis for depressive symptoms in CFS.

 

Source: Scott LV, Dinan TG. Urinary free cortisol excretion in chronic fatigue syndrome, major depression and in healthy volunteers. J Affect Disord. 1998 Jan;47(1-3):49-54. http://www.ncbi.nlm.nih.gov/pubmed/9476743

 

Salivary cortisol profiles in chronic fatigue syndrome

Abstract:

Salivary cortisol profiles (hourly sampling over a 16-hour period) of 10 patients with chronic fatigue syndrome (CFS) but without concurrent depressive disorder were compared with those of 10 healthy volunteers matched for age, sex and menstrual cycle. The mean saliva cortisol concentration over the 16-hour period was slightly but significantly greater in the patients than the controls (p < 0.05). These findings are at variance with earlier reports that CFS is a hypocortisolaemic state and suggest that in CFS the symptom of fatigue is not caused by hypocortisolaemia.

 

Source: Wood B, Wessely S, Papadopoulos A, Poon L, Checkley S. Salivary cortisol profiles in chronic fatigue syndrome. Neuropsychobiology. 1998;37(1):1-4. http://www.ncbi.nlm.nih.gov/pubmed/9438265

 

Giving thyroid hormones to clinically hypothyroid but biochemically euthyroid patients. Long-term treatment is being used

Editor—During the past six months I have become aware of an increasing number of patients with normal results of thyroid function tests who are being treated with a daily dose of up to 100 ìg thyroxine—mainly as a result of publicity being given in the lay media to a hypothesis put forward by Gordon R B Skinner and colleagues.2 These biochemically euthyroid patients invariably have several symptoms that are compatible with a clinical diagnosis of hypothyroidism, but many of them also have agreed diagnostic criteria for the chronic fatigue syndrome, a condition that does involve dysfunction of the hypothalamic-pituitary axis but not hypothyroidism.

You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2127520/pdf/9345188.pdf

 

Source: Shepherd C. Giving thyroid hormones to clinically hypothyroid but biochemically euthyroid patients. Long-term treatment is being used. BMJ. 1997 Sep 27;315(7111):814. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2127520/pdf/9345188.pdf

 

Pathogenesis and management of delayed orthostatic hypotension in patients with chronic fatigue syndrome

Abstract:

The relationship between orthostatic hypotension and chronic fatigue syndrome (CFS) has been reported previously. To study the pathogenesis and management of delayed orthostatic hypotension in patients with CFS, a case comparison study with follow-up of 8 weeks has been designed.

A group of 78 patients with CFS (mean age 40 years; 49% men and 51% women), who fulfilled the Centre for Disease Control and Prevention criteria were studied. There were 38 healthy controls (mean age 43 years; 47% men and 53% women).

At entry to the study each subject underwent an upright tilt-table test, and clinical and laboratory evaluation. Patients with orthostatic hypotension were offered therapy with sodium chloride (1200 mg) in a sustained-release formulation for 3 weeks, prior to resubmission to the tilt-table testing, and clinical and laboratory evaluation.

An abnormal response to upright tilt was observed in 22 of 78 patients with CFS. After sodium chloride therapy for 8 weeks, tilt-table testing was repeated on the 22 patients with an abnormal response at baseline. Of these 22 patients, 10 redeveloped orthostatic hypotension, while 11 did not show an abnormal response to the test and reported an improvement of CFS symptoms.

However, those CFS patients who again developed an abnormal response to tilt-test had a significantly reduced plasma renin activity (0.79 pmol/ml per h) compared both with healthy controls (1.29 pmol/ml per h) and with those 11 chronic fatigue patients (1.0 pmol/ml per h) who improved after sodium chloride therapy (p = 0.04).

In conclusion, in our study CFS patients who did not respond to sodium chloride therapy were found to have low plasma renin activity. In these patients an abnormal renin-angiotensin-aldosterone system could explain the pathogenesis of orthostatic hypotension and the abnormal response to treatment.

 

Source: De Lorenzo F, Hargreaves J, Kakkar VV. Pathogenesis and management of delayed orthostatic hypotension in patients with chronic fatigue syndrome. Clin Auton Res. 1997 Aug;7(4):185-90. http://www.ncbi.nlm.nih.gov/pubmed/9292244