Tag: hypothalamic disorder

Clinical characteristics of patients with unexplainable hypothalamic disorder diagnosed by the corticotropin-releasing hormone challenge test: a retrospective study

Abstract

Background: The corticotropin-releasing hormone (CRH) challenge test can distinguish the disorders of the hypothalamus from those of the pituitary. However, the pathophysiology of hypothalamic disorder (HD) has not been fully understood. This study aimed to elucidate the clinical characteristics of patients with unexplainable HD, diagnosed by the CRH challenge test.

Methods: We retrospectively reviewed patients who underwent the CRH challenge test. Patients were categorized into four groups as follows: patients with peak serum cortisol ≥18 μg/dL were assigned to the normal response (NR) group (n = 18), among patients with peak serum cortisol < 18 μg/dL and peak adrenocorticotropic hormone (ACTH) increase ≥two-fold, patients without obvious background pathology were assigned to the unexplainable-HD group (n = 18), whereas patients with obvious background pathology were assigned to the explainable-HD group (n = 38), and patients with peak serum cortisol < 18 μg/dL and peak ACTH increase <two-fold were assigned to the pituitary disorder (PD) group (n = 15). Inter-group comparisons were performed based on clinical characteristics.

Results: In the CRH challenge test, the peak plasma ACTH levels were significantly lower in the unexplainable-HD group than in the NR group, despite more than two-fold increase compared to basal levels. The increase in serum cortisol was significantly higher in the unexplainable-HD group than in the explainable-HD and PD groups. Although patients in the unexplainable-HD group showed a clear ACTH response in the insulin tolerance test, some patients had peak serum cortisol levels of < 18 μg/dL. Furthermore, attenuated diurnal variations and low normal levels of urinary free cortisol were observed. Most patients in the unexplainable-HD group were young women with chronic fatigue. However, supplementation with oral hydrocortisone at physiological doses reduced fatigue only in some patients.

Conclusions: Patients with unexplainable HD diagnosed by the CRH challenge test had hypothalamic-pituitary-adrenal (HPA) axis dysfunction and some patients had mild central adrenal insufficiency. Hydrocortisone supplementation reduced fatigue only in some patients, suggesting that HPA axis dysfunction may be a physiological adaptation. Further investigation of these patients may help elucidate the pathophysiology of myalgic encephalitis/chronic fatigue syndrome.

Source: Hataya Y, Okubo M, Hakata T, Fujimoto K, Iwakura T, Matsuoka N. Clinical characteristics of patients with unexplainable hypothalamic disorder diagnosed by the corticotropin-releasing hormone challenge test: a retrospective study. BMC Endocr Disord. 2022 Dec 9;22(1):312. doi: 10.1186/s12902-022-01237-7. PMID: 36494805; PMCID: PMC9733005. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9733005/ (Full text)

A Paradigm for Post-Covid-19 Fatigue Syndrome Analogous to ME/CFS

Abstract:

A significant proportion of COVID-19 patients are suffering from prolonged Post-COVID-19 Fatigue Syndrome, with characteristics typically found in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). However, no clear pathophysiological explanation, as yet, has been provided. A novel paradigm for a Post-COVID-19 Fatigue Syndrome is developed here from a recent unifying model for ME/CFS. Central to its rationale, SARS-CoV-2, in common with the triggers (viral and non-viral) of ME/CFS, is proposed to be a physiologically severe stressor, which could be targeting a stress-integrator, within the brain: the hypothalamic paraventricular nucleus (PVN). It is proposed that inflammatory mediators, released at the site of COVID-19 infection, would be transmitted as stress-signals, via humoral and neural pathways, which overwhelm this stress-center.

In genetically susceptible people, an intrinsic stress-threshold is suggested to be exceeded causing ongoing dysfunction to the hypothalamic PVN’s complex neurological circuitry. In this compromised state, the hypothalamic PVN might then be hyper-sensitive to a wide range of life’s ongoing physiological stressors. This could result in the reported post-exertional malaise episodes and more severe relapses, in common with ME/CFS, that perpetuate an ongoing disease state.

When a certain stress-tolerance-level is exceeded, the hypothalamic PVN can become an epicenter for microglia-induced activation and neuroinflammation, affecting the hypothalamus and its proximal limbic system, which would account for the range of reported ME/CFS-like symptoms. A model for Post-COVID-19 Fatigue Syndrome is provided to stimulate discussion and critical evaluation. Brain-scanning studies, incorporating increasingly sophisticated imaging technology should enable chronic neuroinflammation to be detected, even at a low level, in the finite detail required, thus helping to test this model, while advancing our understanding of Post-COVID-19 Fatigue Syndrome pathophysiology.

Source: Mackay A. A Paradigm for Post-Covid-19 Fatigue Syndrome Analogous to ME/CFS. Front Neurol. 2021 Aug 2;12:701419. doi: 10.3389/fneur.2021.701419. PMID: 34408721; PMCID: PMC8365156. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8365156/ (Full text)

Melatonin levels in women with fibromyalgia and chronic fatigue syndrome

Abstract:

OBJECTIVE: Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are stress associated disorders mainly affecting women. FM is characterized primarily by widespread musculoskeletal pain, and CFS by profound debilitating fatigue, but there is considerable overlap of clinical symptoms between these 2 syndromes. Neuroendocrine abnormalities have been noted in both FM and CFS and desynchronization of circadian systems has been postulated in their etiology. The pineal hormone melatonin is involved in synchronizing circadian systems and the use of exogenous melatonin has become widespread in patients with FM and CFS.

METHODS: We examined the characteristics and relationship of melatonin and cortisol levels in premenopausal women with FM (n = 9) or CFS (n = 8), compared to age and menstrual cycle phase matched controls. Blood was collected from an indwelling intravenous catheter every 10 min over 24 h, and plasma melatonin and cortisol were determined by radioimmunoassay at 60 and 10 min intervals, respectively.

RESULTS: Night time (23:00-06:50) plasma melatonin levels were significantly higher in FM patients compared to controls (p<0.05), but there was no significant difference in melatonin levels between CFS patients and controls. No differences in the timing of cortisol and melatonin secretory patterns and no internal desynchronization of the 2 rhythms were found in either patient group, compared to controls.

CONCLUSION: Raised plasma melatonin concentrations have been documented in several other conditions that are associated with dysregulation of neuroendocrine axes. Increased melatonin levels may represent a marker of increased susceptibility to stress induced hypothalamic disruptions. These data indicate that there is no rationale for melatonin replacement therapy in patients with FM and CFS.

 

Source: Korszun A, Sackett-Lundeen L, Papadopoulos E, Brucksch C, Masterson L, Engelberg NC, Haus E, Demitrack MA, Crofford L. Melatonin levels in women with fibromyalgia and chronic fatigue syndrome. J Rheumatol. 1999 Dec;26(12):2675-80. http://www.ncbi.nlm.nih.gov/pubmed/10606381

 

Corticotropin releasing hormone in the pathophysiology of melancholic and atypical depression and in the mechanism of action of antidepressant drugs

Abstract:

Hypercortisolism in depression seems to preferentially reflect activation of hypothalamic CRH secretion. Although it has been postulated that this hypercortisolism is an epiphenomenon of the pain and stress of major depression, our data showing preferential participation of AVP in the hypercortisolism of chronic inflammatory disease suggest specificity for the pathophysiology of hypercortisolism in depression.

Our findings that imipramine causes a down-regulation of the HPA axis in experimental animals and healthy controls support an intrinsic role for CRH in the pathophysiology of melancholia and in the mechanism of action of psychotropic agents. Our data suggest that hypercortisolism is not the only form of HPA dysregulation in major depression.

In a series of studies, commencing in patients with Cushing’s disease, and extending to hyperimmune fatigue states such as chronic fatigue syndrome and examples of atypical depression such as seasonal affective disorder, we have advanced data suggesting hypofunction of hypothalamic CRH neurons. These data raise the question that the hyperphagia, hypersomnia, and fatigue associated with syndromes of atypical depression could reflect a central deficiency of a potent arousal-producing anorexogenic neuropeptide.

In the light of data presented elsewhere in this symposium regarding the role of a hypofunctioning hypothalamic CRH neuron in susceptibility to inflammatory disease, these data also raise the question of a common pathophysiological mechanism in syndromes associated both with inflammatory manifestations and atypical depressive symptoms. This concept of hypofunctioning of hypothalamic CRH neurons in these disorders also raises the question of novel forms of neuropharmacological intervention in both inflammatory diseases and atypical depressive syndromes.

 

Source: Gold PW, Licinio J, Wong ML, Chrousos GP. Corticotropin releasing hormone in the pathophysiology of melancholic and atypical depression and in the mechanism of action of antidepressant drugs. Ann N Y Acad Sci. 1995 Dec 29;771:716-29. http://www.ncbi.nlm.nih.gov/pubmed/8597444

 

Abnormal arginine-vasopressin secretion and water metabolism in patients with postviral fatigue syndrome

Abstract:

Water metabolism and the responses of the neurohypophysis to changes in plasma osmolality during the water loading and water deprivation tests were studied in nine patients with postviral fatigue syndrome (PVFS) and eight age and six-matched healthy control subjects. Secretion of arginine-vasopressin (AVP) was erratic in these patients as shown by lack of correlation between serum and urine osmolality and the corresponding plasma AVP levels. Patients with PVFS had significantly low baseline arginine-vasopressin levels when compared with healthy subjects. Patients with PVFS as a group also showed evidence of increased total body water content. These results may be indicative of hypothalamic dysfunction in patients with PVFS.

 

Source: Bakheit AM, Behan PO, Watson WS, Morton JJ. Abnormal arginine-vasopressin secretion and water metabolism in patients with postviral fatigue syndrome. Acta Neurol Scand. 1993 Mar;87(3):234-8. http://www.ncbi.nlm.nih.gov/pubmed/8475696

 

The neuropsychiatry of chronic fatigue syndrome

Abstract:

This paper explores the relationship between chronic fatigue syndrome (CFS) and psychiatric disorder, with special reference to neuropsychiatry, Topics reviewed include (1) epidemiological evidence of central disorder in CFS; (2) evidence from longitudinal studies of an interaction between vulnerability to CFS and psychiatric disorder; and (3) evidence from neuroimaging, neuropsychology, neurophysiology and neuroendocrinology of disordered CNS function in CFS. The most impressive evidence of CNS disturbance comes from neuroendocrinological studies, which suggest a role of hypothalamic disorder as a final common pathway for CFS. It is concluded that the equal and opposite tendencies of psychiatry to be ‘brainless’ and neurology to be ‘mindless’ have led to needless controversy over the nature of CFS. Now that the contributions of psychiatric disorder to CFS, and of neurobiological dysfunction to psychiatric disorder, are both established, it will be possible to make real advances in understanding the nature of CFS.

 

Source: Wessely S. The neuropsychiatry of chronic fatigue syndrome. Ciba Found Symp. 1993;173:212-29; discussion 229-37. http://www.ncbi.nlm.nih.gov/pubmed/8491099