TGI Friday! Our weekly round-up of recently published research abstracts | 14 March 2014

From the European Journal of Clinical Investigation, Draft text put online 7 March 2014 (full paper available).

Review

Malfunctioning of the autonomic nervous system in patients with Chronic Fatigue Syndrome: A systematic literature review

Deborah Van Cauwenbergh (1,2), Jo Nijs (1,3), Daphne Kos (4), Laura Van Weijnen (1), Filip Struyf (1,2), Mira Meeus (2,5).
1) Pain in Motion Research Group, Departments of Human Physiology and Rehabilitation Sciences, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Belgium
2) Pain in Motion Research Group, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium
3) Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Belgium
4) Occupational therapy, Artesis Plantijn Antwerp & KU Leuven, Belgium
5) Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Belgium

Abstract

INTRODUCTION

It is hypothesized that the autonomic nervous system responds differently to various stressors in patients with chronic fatigue syndrome (CFS) compared to healthy controls. The goal is to systematically review the scientific literature addressing the functioning of the autonomic nervous system in patients with CFS.

MATERIALS AND METHODS

All studies that were identified through electronic databases (PubMed and Web of Science) were screened for eligibility based on selection criteria and assessed (2 independent raters) for methodological quality by using a methodological checklist for case-control studies.

RESULTS

Twenty-seven case-control studies were included. The methodological quality varied between 50% and 71,4%. Some studies
showed different responses to head-up tilt and other autonomous testing.

CONCLUSION

Although comparison between the included case-control studies was difficult, we can conclude that there are differences in
autonomous response between CFS patients and healthy controls. The heart rate dynamic response during the head-up tilt test differs between CFS patients and healthy controls, supporting the increased prevalence of postural orthostatic tachycardia syndrome. The autonomic response can be useful for the diagnosis of CFS.


From the Journal of the Chinese Medical Association, published on line on 7 Marc 2014.

RBC volume deficiency in patients with excessive orthostatic decrease in cerebral blood flow velocity

Chun-Jen Lin (1), Yum-Kung Chu (2), Chang-Ming Chern (3)
1) Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
Department of Internal Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
2) Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
3) Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
Corresponding Author InformationCorresponding author. Dr. Chang-Ming Chern, Department of Neurology, Taipei Veterans General Hospital, 201, Section 2, Shi-Pai Road, Taipei 112, Taiwan, ROC.

Abstract

BACKGROUND

Orthostatic intolerance (OI) is common but heterogeneous. There is a subgroup of OI patients who have excessive decrease in cerebral blood flow velocity (CBFV) of bilateral middle cerebral arteries (MCAs) during head-up tilt without systemic blood pressure
change. This study evaluated the role of blood volume reduction in such patients.

METHODS

Patients with idiopathic OI who had excessive orthostatic decrease (>20% of the supine level) in mean CBFV of bilateral MCAs and who also received blood volume determination were collected. The chromium (51Cr) dilution method was used for red blood cell (RBC)
volume determination in these patients. The blood volume was expressed as a percentage of the expected volume.

These patients were further divided into two groups, those with postural tachycardia syndrome (POTS group) and those without (non-POTS group). The data of RBC volume were compared between the two groups. Besides, we used multivariate linear regression to evaluate the factors that predict RBC volume.

RESULTS

Twenty-five patients (13 females, median age = 28 years) were enrolled in this study. Nine of these patients had POTS (5 females, median age = 26 years) and 16 did not (8 females, median age = 29.5 years).

Compared with the expected volume, the RBC volume was significantly reduced in all patients (median = 82% of the expected volume). Moreover, the RBC volume was significantly lower in the POTS group than that in the non-POTS group (78% vs. 85% of the expected
volume, p = 0.013). The orthostatic decrease of MCA flow velocity was 28.3% in the POTS group and 32.5% in the non-POTS group (p = 0.140).

The orthostatic pulsatility index increment was 15.4% in the POTS group and 20.5% in the non-POTS group (p = 0.438). Moreover, basic demography and hemoglobin levels were not different between the two groups. After multivariate linear regression (dependent variables including age, sex, body surface, and groups), only the presence of POTS significantly predicted the RBC volume (p = 0.006).

CONCLUSION

The results of our study indicated that low RBC volume may play an important role in the pathophysiology of OI in this group of patients. Moreover, its role seems even more relevant in patients with POTS than in those without. Further studies for mechanistic evaluation are needed in the future.


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