Category: Pathophysiology

Reduction of serotonin transporters of patients with chronic fatigue syndrome

Abstract:

To assess the involvement of serotonin in the symptoms of chronic fatigue syndrome, we investigated the serotonergic neurotransmitter system of chronic fatigue syndrome patients by the positron emission tomography (PET).

Here we show that the density of serotonin transporters (5-HTTs) in the brain, as determined by using a radiotracer, [C](+)McN5652, was significantly reduced in the rostral subdivision of the anterior cingulate as compared with that in normal volunteers. This subdivision is different from that in the dorsal anterior cingulate in which binding potential values of individual patient showed a weak negative correlation with self-reported pain score of the patients.

Therefore, an alteration of serotonergic system in the rostral anterior cingulate plays a key role in pathophysiology of chronic fatigue syndrome.

 

Source: Yamamoto S, Ouchi Y, Onoe H, Yoshikawa E, Tsukada H, Takahashi H, Iwase M, Yamaguti K, Kuratsune H, Watanabe Y. Reduction of serotonin transporters of patients with chronic fatigue syndrome. Neuroreport. 2004 Dec 3;15(17):2571-4. http://www.ncbi.nlm.nih.gov/pubmed/15570154

 

Diminished central activation during maximal voluntary contraction in chronic fatigue syndrome

Abstract:

OBJECTIVE: We have investigated whether central activation failure (CAF) is increased during local muscle fatigue in chronic fatigue syndrome (CFS).

METHODS: Fourteen female CFS patients and 14 age-matched healthy female controls made a 2 min sustained maximal voluntary contraction (MVC) of the biceps brachii muscle. Before, during, and after sustained MVC, electrical endplate stimulation was applied. Force and 5 channel surface EMG (sEMG) were registered.

RESULTS: Although force responses upon stimulation during rest did not differ between patients and controls, MVC was significantly lower in patients. Already at the beginning of sustained MVC, CFS patients showed significantly larger CAF than controls (36.5+/-17.0% and 12.9+/-13.3%, respectively). For all individual patients mean CAF over the first 45 s was higher than 30%, while it was below 30% for all controls. Less peripheral fatigue in patients was demonstrated by the changes in muscle fibre conduction velocity and the differences between force responses before and after contraction.

CONCLUSIONS: Central activation is diminished in CFS patients. Possible causes include changed perception, impaired concentration, reduced effort and physiologically defined changes, e.g. in the corticospinal excitability or the concentration of neurotransmitters. As a consequence, demands on the muscle are lower, resulting in less peripheral fatigue.

SIGNIFICANCE: CFS patients show reduced central activation during MVC. The underlying pathophysiological processes remain still to be determined.

 

Source: Schillings ML, Kalkman JS, van der Werf SP, van Engelen BG, Bleijenberg G, Zwarts MJ. Diminished central activation during maximal voluntary contraction in chronic fatigue syndrome. Clin Neurophysiol. 2004 Nov;115(11):2518-24. http://www.ncbi.nlm.nih.gov/pubmed/15465441

 

Chronic fatigue syndrome impairs circadian rhythm of activity level

Abstract:

Some of the symptoms of chronic fatigue syndrome (CFS) are the same as for disrupted circadian rhythm. Activity level is frequently used to study circadian rhythm. Continuous waist activity measurements taken every minute 24 h/day for from 5 to 7 days in 10 controls and from 2 to 7 days in 8 patients with CFS yielded two primary findings: (a) lower daytime activity and (b) less regular activity-rest cycles in persons with CFS than in controls.

 

Source: Tryon WW, Jason L, Frankenberry E, Torres-Harding S. Chronic fatigue syndrome impairs circadian rhythm of activity level. Physiol Behav. 2004 Oct 15;82(5):849-53. http://www.ncbi.nlm.nih.gov/pubmed/15451649

 

In vivo magnetic resonance spectroscopy in chronic fatigue syndrome

Abstract:

The pathogenic mechanisms of chronic fatigue syndrome (CFS) are not clearly known. Fatigue, poor short-term memory and muscle pain are the most disabling symptoms in CFS. Research data on magnetic resonance spectroscopy (MRS) of muscles and brain in CFS patients suggest a cellular metabolic abnormality in some cases.

31P MRS of skeletal muscles in a subset of patients indicate early intracellular acidosis in the exercising muscles. 1H MRS of the regional brain areas in CFS have shown increased peaks of choline derived from the cell membrane phospholipids.

Cell membrane oxidative stress may offer a common explanation for the observed MRS changes in the muscles and brain of CFS patients and this may have important therapeutic implications. As a research tool, MRS may be used as an objective outcome measure in the intervention studies. In addition, regional brain 1H MRS has the potential for wider use to substantiate a clinical diagnosis of CFS from other disorders of unexplained chronic fatigue.

 

Source: Chaudhuri A, Behan PO. In vivo magnetic resonance spectroscopy in chronic fatigue syndrome. Prostaglandins Leukot Essent Fatty Acids. 2004 Sep;71(3):181-3. http://www.ncbi.nlm.nih.gov/pubmed/15253888

 

Neural correlates of the chronic fatigue syndrome–an fMRI study

Abstract:

Chronic fatigue syndrome (CFS) is characterized by a debilitating fatigue of unknown aetiology. Patients who suffer from CFS report a variety of physical complaints as well as neuropsychological complaints. Therefore, it is conceivable that the CNS plays a role in the pathophysiology of CFS. The purpose of this study was to investigate neural correlates of CFS, and specifically whether there exists a linkage between disturbances in the motor system and CFS.

We measured behavioural performance and cerebral activity using rapid event-related functional MRI in 16 CFS patients and 16 matched healthy controls while they were engaged in a motor imagery task and a control visual imagery task. CFS patients were considerably slower on performance of both tasks, but the increase in reaction time with increasing task load was similar between the groups.

Both groups used largely overlapping neural resources. However, during the motor imagery task, CFS patients evoked stronger responses in visually related structures. Furthermore, there was a marked between-groups difference during erroneous performance. In both groups, dorsal anterior cingulate cortex was specifically activated during error trials. Conversely, ventral anterior cingulate cortex was active when healthy controls made an error, but remained inactive when CFS patients made an error.

Our results support the notion that CFS may be associated with dysfunctional motor planning. Furthermore, the between-groups differences observed during erroneous performance point to motivational disturbances as a crucial component of CFS.

 

Source: de Lange FP, Kalkman JS, Bleijenberg G, Hagoort P, van der Werf SP, van der Meer JW, Toni I. Neural correlates of the chronic fatigue syndrome–an fMRI study. Brain. 2004 Sep;127(Pt 9):1948-57. Epub 2004 Jul 7. http://brain.oxfordjournals.org/content/127/9/1948.long (Full article)

 

Midodrine treatment for chronic fatigue syndrome

Abstract:

The long term results of midodrine treatment in a patient having debilitating chronic fatigue syndrome (CFS) are reported. Midodrine treatment, directed at the autonomic nervous system, resulted in correction of the dysautonomia followed by improvement of fatigue. This finding is consistent with the hypothesis that dysautonomia plays a major part in the pathophysiology of CFS and that therapies directed at the autonomic nervous system may be effective in the treatment of CFS.

 

Source: Naschitz J, Dreyfuss D, Yeshurun D, Rosner I. Midodrine treatment for chronic fatigue syndrome. Postgrad Med J. 2004 Apr;80(942):230-2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1742969/pdf/v080p00230.pdf (Full article)

 

Alcohol use in chronic fatigue syndrome

Abstract:

OBJECTIVE: To examine the anecdotal observation that patients with chronic fatigue syndrome develop alcohol intolerance.

METHODS: A consecutive case series of 114 patients fulfilling UK criteria for chronic fatigue syndrome referred to a specialist clinic. Self-reported alcohol use pre- and postdiagnosis, fatigue symptoms and comorbidity measures were collected.

RESULTS: Two-thirds reduced alcohol intake. The most common reasons were increased tiredness after drinking (67%), increased nausea (33%), exacerbated hangovers (23%) and sleep disturbance (24%). One-third of the subjects also stopped drinking because “it seemed sensible.” Some had been advised to avoid alcohol, but the majority (66%) did so on the basis of personal experience.

CONCLUSION: Our data supports the anecdotal belief that chronic fatigue syndrome patients reduce or cease alcohol intake. This is associated with greater impairment in employment, leisure and social domains of function, and may hint at psycho-pathophysiological processes in common with other conditions that result in alcohol intolerance.

 

Source: Woolley J, Allen R, Wessely S. Alcohol use in chronic fatigue syndrome. J Psychosom Res. 2004 Feb;56(2):203-6. http://www.ncbi.nlm.nih.gov/pubmed/15016579

 

Dysautonomia in chronic fatigue syndrome: facts, hypotheses, implications

Abstract:

The diagnosis of chronic fatigue syndrome (CFS) is based on patient history and treatment on cognitive behavior therapy and graded exercise. There is increasing evidence that dysautonomia occurs in CFS manifest primarily as disordered regulation of cardiovascular responses to stress. We impart our experience relating to diagnosis, monitoring, and treatment of CFS based on identification and management of dysautonomia.

Recently proposed methods for assessment of the cardiovascular reactivity, the ‘hemodynamic instability score’ (HIS) and the ‘Fractal and Recurrence Analysis-based Score’ (FRAS), served for this purpose. On HUTT, a particular dysautonomia is revealed in CFS patients that differ from dysautonomia in several other disorders. This distinct abnormality in CFS can be identified by HIS >-0.98 (sensitivity 84.5% and specificity 85.1%) and FRAS > +0.22 (sensitivity 70% and specificity 88%). Therefore, the HIS and FRAS may be used, in the appropriate clinical context, to support the diagnosis of CFS, which until now, could only be subjectively inferred.

A pilot study suggested that midodrine treatment, directed at the autonomic nervous system in CFS, results first in correction of dysautonomia followed by improvement of fatigue. This finding implies that dysautonomia is pivotal in the pathophysiology CFS, at least in a large part of the patients, and that manipulating the autonomic nervous system may be effective in the treatment of CFS.

 

Source: Naschitz JE, Yeshurun D, Rosner I. Dysautonomia in chronic fatigue syndrome: facts, hypotheses, implications. Med Hypotheses. 2004;62(2):203-6. http://www.ncbi.nlm.nih.gov/pubmed/14962627

 

Neuroendocrine aspects of chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a serious health concern affecting over 800000 Americans of all ages, races, socioeconomic groups and genders. The etiology and pathophysiology of CFS are unknown, yet studies have suggested an involvement of the neuroendocrine system. A symposium was organized in March 2001 to explore the possibility of an association between neuroendocrine dysfunction and CFS, with special emphasis on the interactions between neuroendocrine dysfunction and other abnormalities noted in the immune and autonomic nervous systems of individuals with CFS. This paper represents the consensus of the panel of experts who participated in this meeting.

Copyright 2004 S. Karger AG, Basel

 

Source: Papanicolaou DA1, Amsterdam JD, Levine S, McCann SM, Moore RC, Newbrand CH, Allen G, Nisenbaum R, Pfaff DW, Tsokos GC, Vgontzas AN, Kales A. Neuroendocrine aspects of chronic fatigue syndrome. Neuroimmunomodulation. 2004;11(2):65-74. http://www.ncbi.nlm.nih.gov/pubmed/14758052

 

Systemic Mycoplasma blood infection in fibromyalgia and chronic fatigue syndrome

Fibromyalgia and chronic fatigue syndrome is characterized by the lack of specific symptoms and laboratory abnormalities.

Most patients with one or both syndromes have mycoplasma infection, claimed to be regenerating return to their premorbid state after long-term antibiotic therapy, and the infection can not be detected after recovery.

Further prospective studies should determine whether such an infection is present in a relatively larger proportion of all patient populations with these syndromes.

The article is partly based on an article published in  Rheumatology International 2003

You can read the rest of this article here: http://tidsskriftet.no/article/960407

 

Source: Endresen GK. Systemic Mycoplasma blood infection in fibromyalgia and chronic fatigue syndrome. Tidsskr Nor Laegeforen. 2004 Jan 22;124(2):203-5. [Article in Norwegian] http://tidsskriftet.no/article/960407 (Full article)