Tag: autonomic dysfunction

Cerebral vascular control is associated with skeletal muscle pH in chronic fatigue syndrome patients both at rest and during dynamic stimulation

Abstract:

Cerebral blood flow (CBF) is maintained despite changing systemic blood pressure through cerebral vascular control, with such tight regulation believed to be under local tissue control. Chronic fatigue syndrome (CFS) associates with a wide range of symptoms, including orthostatic intolerance, skeletal muscle pH abnormalities and cognitive impairment.

CFS patients are known to have reduced CBF and orthostatic intolerance associates with abnormal vascular regulation, while skeletal muscle pH abnormalities associate with autonomic dysfunction. These findings point to autonomic dysfunction as the central feature of CFS, and cerebral vascular control being influenced by factors outside of the brain, a macroscopic force affecting the stability of regional regulation. We therefore explored whether there was a physiological link between cerebral vascular control and skeletal muscle pH management in CFS. Seventeen consecutive CFS patients fulfilling the Fukuda criteria were recruited from our local CFS clinical service. To probe the static scenario, CBF and skeletal muscle pH were measured at rest using MRI and (31)P magnetic resonance spectroscopy ((31)P-MRS). To examine dynamic control, brain functional MRI was performed concurrently with Valsalva manoeuvre (VM), a standard autonomic function challenge, while (31)P-MRS was performed during plantar flexion exercise.

Significant inverse correlation was seen between CBF and skeletal muscle pH at rest (r = – 0.67, p < 0.01). Prolonged cerebral vascular constriction during the sympathetic phase of VM was associated with higher pH in skeletal muscle after plantar flexion exercise (r = 0.69, p < 0.008). In conclusion, cerebral vascular control is closely related to skeletal muscle pH both at rest and after dynamic stimulation in CFS.

 

Source: He J, Hollingsworth KG, Newton JL, Blamire AM. Cerebral vascular control is associated with skeletal muscle pH in chronic fatigue syndrome patients both at rest and during dynamic stimulation. Neuroimage Clin. 2013 Jan 5;2:168-73. doi: 10.1016/j.nicl.2012.12.006. ECollection 2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777833/ (Full article)

 

Relationship between autonomic cardiovascular control, case definition, clinical symptoms, and functional disability in adolescent chronic fatigue syndrome: an exploratory study

Abstract:

Chronic Fatigue Syndrome (CFS) is characterized by severe impairment and multiple symptoms. Autonomic dysregulation has been demonstrated in several studies. We aimed at exploring the relationship between indices of autonomic cardiovascular control, the case definition from Centers for Disease Control and Prevention (CDC criteria), important clinical symptoms, and disability in adolescent chronic fatigue syndrome.

38 CFS patients aged 12-18 years were recruited according to a wide case definition (ie. not requiring accompanying symptoms) and subjected to head-up tilt test (HUT) and a questionnaire. The relationships between variables were explored with multiple linear regression analyses. In the final models, disability was positively associated with symptoms of cognitive impairments (p<0.001), hypersensitivity (p<0.001), fatigue (p=0.003) and age (p=0.007).

Symptoms of cognitive impairments were associated with age (p=0.002), heart rate (HR) at baseline (p=0.01), and HR response during HUT (p=0.02). Hypersensitivity was associated with HR response during HUT (p=0.001), high-frequency variability of heart rate (HF-RRI) at baseline (p=0.05), and adherence to the CDC criteria (p=0.005). Fatigue was associated with gender (p=0.007) and adherence to the CDC criteria (p=0.04).

In conclusion, a) The disability of CFS patients is not only related to fatigue but to other symptoms as well; b) Altered cardiovascular autonomic control is associated with certain symptoms; c) The CDC criteria are poorly associated with disability, symptoms, and indices of altered autonomic nervous activity.

 

Source: Wyller VB, Helland IB. Relationship between autonomic cardiovascular control, case definition, clinical symptoms, and functional disability in adolescent chronic fatigue syndrome: an exploratory study. Biopsychosoc Med. 2013 Feb 7;7(1):5. doi: 10.1186/1751-0759-7-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570350/ (Full article)

 

Clinical characteristics of a novel subgroup of chronic fatigue syndrome patients with postural orthostatic tachycardia syndrome

Abstract:

OBJECTIVES: A significant proportion of patients with chronic fatigue syndrome (CFS) also have postural orthostatic tachycardia syndrome (POTS). We aimed to characterize these patients and differentiate them from CFS patients without POTS in terms of clinical and autonomic features.

METHODS: A total of 179 patients with CFS (1994 Centers for Disease Control and Prevention criteria) attending one of the largest Department of Health-funded CFS clinical services were included in this study. Outcome measures were as follows: (i) symptom assessment tools including the fatigue impact scale, Chalder fatigue scale, Epworth sleepiness scale (ESS), orthostatic grading scale (OGS) and hospital anxiety and depression scale (HADS-A and -D, respectively), (ii) autonomic function analysis including heart rate variability and (iii) haemodynamic responses including left ventricular ejection time and systolic blood pressure drop upon standing.

RESULTS: CFS patients with POTS (13%, n = 24) were younger (29 ± 12 vs. 42 ± 13 years, P < 0.0001), less fatigued (Chalder fatigue scale, 8 ± 4 vs. 10 ± 2, P = 0.002), less depressed (HADS-D, 6 ± 4 vs. 9 ± 4, P = 0.01) and had reduced daytime hypersomnolence (ESS, 7 ± 6 vs. 10 ± 5, P = 0.02), compared with patients without POTS. In addition, they exhibited greater orthostatic intolerance (OGS, 11 ± 5; P < 0.0001) and autonomic dysfunction. A combined clinical assessment tool of ESS ≤9 and OGS ≥9 identifies accurately CFS patients with POTS with 100% positive and negative predictive values.

CONCLUSIONS: The presence of POTS marks a distinct clinical group of CFS patents, with phenotypic features differentiating them from those without POTS. A combination of validated clinical assessment tools can determine which CFS patients have POTS with a high degree of accuracy, and thus potentially identify those who require further investigation and consideration for therapy to control heart rate.

© 2013 The Association for the Publication of the Journal of Internal Medicine.

Comment in: Postural orthostatic tachycardia syndrome as a clinically important subgroup of chronic fatigue syndrome: further evidence for central nervous system dysfunctioning. [J Intern Med. 2013]

 

Source: Lewis I, Pairman J, Spickett G, Newton JL. Clinical characteristics of a novel subgroup of chronic fatigue syndrome patients with postural orthostatic tachycardia syndrome. J Intern Med. 2013 May;273(5):501-10. doi: 10.1111/joim.12022. Epub 2013 Jan 7. http://onlinelibrary.wiley.com/doi/10.1111/joim.12022/full (Full article)

 

Impaired blood pressure variability in chronic fatigue syndrome–a potential biomarker

Abstract:

INTRODUCTION: Autonomic dysfunction is common in chronic fatigue syndrome (CFS). This study set out to derive an autonomic biomarker using a comprehensive assessment of heart rate and blood pressure variability.

METHODS: Heart rate and non-invasive continuous blood pressure measurements (task force monitor) at rest and on standing were performed in CFS (Fukuda n = 68) and matched controls (n = 68) to derive high frequency (HF; parasympathetic) and low frequency (LF; sympathetic) heart rate variability (HRV), systolic (SBPV) and diastolic (DBPV) blood pressure variability. Variables of significance were combined using receiver operator curves to explore the diagnostic utility of parameters particularly at rest.

RESULTS: At rest, LF-HRV (sympathetic) was significantly increased in CFS compared to controls, while parasympathetic markers were significantly reduced (P = 0.006). Total DBP spectral power was increased (P = 0.0003) across all domains, with a shift towards sympathetic and away from parasympathetic SBPV (P = 0.05). On standing, overall SBPV response was significantly reduced with reductions in both sympathetic and parasympathetic components of SBPV (all P < 0.0001). Change in LF-DBP and relative balance of LF/HF DBP on standing differed between CFS and controls (P < 0.0001). Using the 85% sensitivity levels, we determined a threshold for three chosen resting BPV parameters of LF DBP >3.185, rest HF DBP >0.86, rest total DBP >7.05. Achieving all of these differentiated between CFS and controls with 77% sensitivity and 53% specificity.

CONCLUSION: This study has shown that there are objectively measured abnormalities of blood pressure variability in CFS and that these abnormalities have the potential to be a bedside diagnostic tool.

 

Source: Frith J, Zalewski P, Klawe JJ, Pairman J, Bitner A, Tafil-Klawe M, Newton JL. Impaired blood pressure variability in chronic fatigue syndrome–a potential biomarker. QJM. 2012 Sep;105(9):831-8. doi: 10.1093/qjmed/hcs085. Epub 2012 Jun 4. http://qjmed.oxfordjournals.org/content/105/9/831.long (Full article)

 

Autonomic symptoms at baseline and following infectious mononucleosis in a prospective cohort of adolescents

Chronic fatigue syndrome (CFS) is a complex condition involving fatigue and musculoskeletal and cognitive symptoms. Six, 12, and 24 months following monospot-positive acute infectious mononucleosis (IM), 13%, 7%, and 4%, respectively, of adolescents met criteria for CFS.1 As part of their evaluation at baseline and 6, 12, and 24 months following IM, adolescents diagnosed with CFS and recovered controls completed questionnaires regarding autonomic symptoms.

You can read the rest of this article here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3896070/

 

Source: Katz BZ, Stewart JM, Shiraishi Y, Mears CJ, Taylor R. Autonomic symptoms at baseline and following infectious mononucleosis in a prospective cohort of adolescents. Arch Pediatr Adolesc Med. 2011 Aug;165(8):765-6. doi: 10.1001/archpediatrics.2011.124. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3896070/ (Full article)

 

Physical activity intensity but not sedentary activity is reduced in chronic fatigue syndrome and is associated with autonomic regulation

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is a common debilitating condition associated with reduced function and impaired quality of life. The cause is unknown and treatments limited. Studies confirm that CFS is associated with impaired autonomic regulation and impaired muscle function.

AIM: Define the relationship between sedentary behaviour, physical activity and autonomic regulation in people with CFS.

DESIGN: Cohort study.

METHODS: Physical activity was assessed objectively in 107 CFS patients (Fukuda) and age, sex and body mass index (BMI)-matched sedentary controls (n= 107). Fatigue severity was determined using the Fatigue Impact Scale in all participants and heart rate variability performed in the CFS group.

RESULTS: The CFS group had levels and patterns of sedentary behaviour similar to non-fatigue controls (P > 0.05). Seventy-nine percent of the CFS group did not achieve the WHO recommended 10,000 steps per day. Active energy expenditure [time >3 METs (metabolic equivalents)] was reduced in CFS when compared with controls (P < 0.0001). Physical activity duration was inversely associated with resting heart rate (P = 0.04; r(2) = 0.03), with reduced activity significantly associating with reduced heart rate variability in CFS. There were no relationships between fatigue severity and any parameter of activity. Thirty-seven percent of the CFS group were overweight (BMI 25-29.9) and 20% obese (BMI ≥ 30).

CONCLUSION: Low levels of physical activity reported in CFS represent a significant and potentially modifiable perpetuating factor in CFS and are not attributable to high levels of sedentary activity, rather a decrease in physical activity intensity. The reduction in physical activity can in part be explained by autonomic dysfunction but not fatigue severity.

 

Source: Newton JL, Pairman J, Hallsworth K, Moore S, Plötz T, Trenell MI. Physical activity intensity but not sedentary activity is reduced in chronic fatigue syndrome and is associated with autonomic regulation. QJM. 2011 Aug;104(8):681-7. doi: 10.1093/qjmed/hcr029. Epub 2011 Mar 7. http://qjmed.oxfordjournals.org/content/104/8/681.long (Full article)

 

School phobia and childhood chronic fatigue syndrome (CCFS)

Abstract:

Chronic fatigue occurring in previously healthy children and adolescents is a vexing problem encountered by pediatric practitioners and the impact of fatigue in youngsters should not be underestimated. In its severe form, it is often associated with mood disorders. Findings in children and adolescent cases suggest that severe unexplained fatigue might precede the development of fatigue-related illness, such as childhood chronic fatigue syndrome (CCFS). This is a disabling condition characterized by severe disabling fatigue and a combination of symptoms, the prominent features being self-reported impairments in concentration and short-term memory, sleep disturbances and autonomic symptoms that cannot be explained by medical or psychiatric illness. We have encountered such patients with these complaints; their major symptoms include: general fatigue, fever, headache (not migraine), and memory disturbance. From our clinical experience, we have inferred that patients with CCFS might experience changes in brain function levels, which induce an autonomic imbalance and engender symptoms such as general fatigue, higher-order level cognitive dysfunction, and memory disturbance.

 

Source: Tomoda A. School phobia and childhood chronic fatigue syndrome (CCFS). Nihon Rinsho. 2007 Jun;65(6):1121-33. [Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/17561707

 

Autonomic function and child chronic fatigue syndrome

Abstract:

It is postulated that child chronic fatigue syndrome (CFS) involves the autonomic nervous system, although the precise mechanism has not been clearly indicated. This paper reviews recent reports focusing the role of the autonomic nervous system which plays in CFS. Many of the method for measuring autonomic function have appeared in the clinical setting in parallel with advancing computer technology, but these are limited when applied in children. In these blood pressure and heart rate changes during orthostatic stress and these variability are favorably used. As a result, one third of children with CFS showed abnormal cardiovascular adjustment during posture change (orthostatic dysregulation: OD) which is characterized by instantaneous orhthostatic hypotension, postural tachycardia or neurally-mediated syncope. Most of the studies using power spectral analysis of heart rate variability showed sympathetic activation, however no consistent finding has been obtained. In conclusion, autonomic function might be partly involved in CFS such as OD, but its priority in causing CFS is unclear.

 

Source: Tanaka H. Autonomic function and child chronic fatigue syndrome. Nihon Rinsho. 2007 Jun;65(6):1105-12. [Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/17561705

 

Neuroendocrine mechanisms in fibromyalgia-chronic fatigue

Abstract:

Fibromyalgia and chronic fatigue syndrome are poorly understood disorders that share similar demographic and clinical characteristics. Because of the clinical similarities between both disorders it was suggested that they share a common pathophysiological mechanism, namely, central nervous system dysfunction.

This chapter presents data demonstrating neurohormonal abnormalities, abnormal pain processing and autonomic nervous system dysfunction in fibromyalgia and chronic fatigue syndrome. The possible contribution of the central nervous system dysfunction to the development and symptomatology of these conditions is discussed. The chapter concludes by reviewing the effect of current treatments and emerging therapeutic modalities in fibromyalgia and chronic fatigue syndrome.

 

Source: Buskila D, Press J. Neuroendocrine mechanisms in fibromyalgia-chronic fatigue. Best Pract Res Clin Rheumatol. 2001 Dec;15(5):747-58. http://www.ncbi.nlm.nih.gov/pubmed/11812019

 

Autonomic nervous system derangement in fibromyalgia syndrome and related disorders

Abstract:

Fibromyalgia syndrome is a chronic, painful musculoskeletal disorder of unknown etiology and/or pathophysiology. During the last decade many studies have suggested autonomic nervous system involvement in this syndrome, although contradictory results have been reported. This review focuses on studies of the autonomic nervous system in fibromyalgia syndrome and related disorders, such as chronic fatigue syndrome and irritable bowel syndrome on the one hand and anxiety disorder on the other, and highlights techniques of dynamic assessment of heart rate variability. It raises the potentially important prognostic implications of protracted autonomic dysfunction in patient populations with fibromyalgia and related disorders, especially for cardiovascular morbidity and mortality.

 

Source: Cohen H, Neumann L, Kotler M, Buskila D. Autonomic nervous system derangement in fibromyalgia syndrome and related disorders. Isr Med Assoc J. 2001 Oct;3(10):755-60. http://www.ncbi.nlm.nih.gov/pubmed/11692551