Tag: autonomic dysfunction

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

 

Autonomic nervous system dysfunction in adolescents with postural orthostatic tachycardia syndrome and chronic fatigue syndrome is characterized by attenuated vagal baroreflex and potentiated sympathetic vasomotion

Abstract:

The objective was to determine the nature of autonomic and vasomotor changes in adolescent patients with orthostatic tachycardia associated with the chronic fatigue syndrome (CFS) and the postural orthostatic tachycardia syndrome (POTS).

Continuous electrocardiography and arterial tonometry was used to investigate the heart rate and blood pressure responses before and 3-5 min after head-up tilt in 22 adolescents with POTS and 14 adolescents with CFS, compared with control subjects comprising 10 healthy adolescents and 20 patients with simple faint. Heart rate and blood pressure variability, determined baroreceptor function using transfer function analysis, and measured cardiac vagal and adrenergic autonomic responses were calculated using timed breathing and the quantitative Valsalva maneuver.

Two of 10 healthy controls and 14 of 20 simple faint patients experienced vasovagal syncope during head-up tilt. By design, all CFS and POTS patients experienced orthostatic tachycardia, often associated with hypotension. R-R interval and heart rate variability were decreased in CFS and POTS patients compared with control subjects and remained decreased with head-up tilt. Low-frequency (0.05-0.15 Hz) blood pressure variability reflecting vasomotion was increased in CFS and POTS patients compared with control subjects and increased further with head-up tilt. This was associated with depressed baroreflex transfer indicating baroreceptor attenuation through defective vagal efferent response. Only the sympathetic response remained. Heart rate variability declined progressively from normal healthy control subjects through syncope to POTS to CFS patients. Timed breathing and Valsalva maneuver were most often normal in CFS and POTS patients, although abnormalities in select individuals were found.

Heart rate and blood pressure regulation in POTS and CFS patients are similar and indicate attenuated efferent vagal baroreflex associated with increased vasomotor tone. Loss of beat-to-beat heart rate control may contribute to a destabilized blood pressure resulting in orthostatic intolerance. The dysautonomia of orthostatic intolerance in POTS and in chronic fatigue are similar.

 

Source: Stewart JM. Autonomic nervous system dysfunction in adolescents with postural orthostatic tachycardia syndrome and chronic fatigue syndrome is characterized by attenuated vagal baroreflex and potentiated sympathetic vasomotion. Pediatr Res. 2000 Aug;48(2):218-26. http://www.ncbi.nlm.nih.gov/pubmed/10926298

 

Neurally mediated hypotension in fatigued Gulf War veterans: a preliminary report

Abstract:

BACKGROUND: Many patients with chronic fatigue syndrome (CFS) have neurally mediated hypotension when subjected to head-up tilt, suggesting autonomic nervous system dysfunction. Some Gulf War veterans have symptoms similar to CFS. Whether they also tend to have neurally mediated hypotension is unknown.

METHODS: We performed 3-stage tilt-table testing on 14 Gulf War veterans with chronic fatigue, 13 unfatigued control Gulf War veterans, and 14 unfatigued control subjects who did not serve in the Gulf War. Isoproterenol was used in stages 2 and 3 of the tilt protocol.

RESULTS: More fatigued Gulf War veterans than unfatigued control subjects had hypotensive responses to tilt (P < 0.036). A positive response to the drug-free stage 1 of the tilt was observed in 4 of 14 fatigued Gulf War veterans versus 1 of 27 unfatigued control subjects (P < 0.012). Heart rate and heart rate variation during stage 1 was significantly greater in the fatigued group (P < 0.05).

CONCLUSION: We conclude that more fatigued Gulf War veterans have neurally mediated hypotension than unfatigued control subjects, similar to observations in CFS. Autonomic nervous system dysfunction may be present in some fatigued Gulf War veterans.

 

Source: Davis SD, Kator SF, Wonnett JA, Pappas BL, Sall JL. Neurally mediated hypotension in fatigued Gulf War veterans: a preliminary report. Am J Med Sci. 2000 Feb;319(2):89-95. http://www.ncbi.nlm.nih.gov/pubmed/10698092

 

Autonomic function in patients with chronic fatigue syndrome

Abstract:

Subtle signs of autonomic dysfunction and orthostatic intolerance have been reported in patients with chronic fatigue syndrome (CFS). To assess cardiovascular autonomic function noninvasively in an unselected group of patients with CFS, we examined responsiveness to several cardiovascular reflex tests in 37 CFS patients and 38 healthy control subjects.

Blood pressure and heart rate (HR) were recorded continuously by a Finapres device before and during forced breathing, standing up, Valsalva maneuver, and sustained handgrip exercise (HG). In addition, a mental arithmetic test was carried out and questionnaires to assess the severity of CFS symptoms were completed.

At rest, there were no significant differences in blood pressure or in HR between the two groups. The in- and expiratory difference in HR tended to be lower in CFS patients (28.4 +/- 10.5 beats) than in healthy controls (32.2 +/- 9.5) (p = 0.11). The maximal increase in HR during standing up was not significantly different between the CFS group (37.6 +/-8.9 beats) and the control group (40.2 +/- 8.9 beats). There were no significant differences between both groups with regard to the Valsalva ratio, but the systolic and diastolic blood pressure responses were significantly larger in CFS patients, despite the fact that many CFS patients were not able to sustain the Valsalva maneuver. The HR response to MA was significantly less in the CFS group (22.6 +/- 9.9) than in the control group (29.5 +/- 16.7) (p < 0.05), suggesting impaired cardiac sympathetic responsiveness to mental stress. The lower HR responses could not be explained by the level of concentration in the CFS group.

During HG exercise, the hemodynamic responses were lower in the CFS group than in the control group, but this might be attributed to the lower level of muscle exertion in CFS patients. There were no significant differences between CFS patients with and without symptoms of autonomic dysfunction regarding the hemodynamic responses to the cardiovascular reflex tests. The findings of the study suggest that there are no gross alterations in cardiovascular autonomic function in patients with CFS.

 

Source: Soetekouw PM, Lenders JW, Bleijenberg G, Thien T, van der Meer JW. Autonomic function in patients with chronic fatigue syndrome. Clin Auton Res. 1999 Dec;9(6):334-40. http://www.ncbi.nlm.nih.gov/pubmed/10638807

 

Neurally mediated hypotension and autonomic dysfunction measured by heart rate variability during head-up tilt testing in children with chronic fatigue syndrome

Abstract:

Recent investigations suggest a role for neurally mediated hypotension (NMH) in the symptomatology of chronic fatigue syndrome (CFS) in adults. Our previous observations in children with NMH and syncope (S) unrelated to CFS indicate that the modulation of sympathetic and parasympathetic tone measured by indices of heart rate variability (HRV) is abnormal in children who faint during head-up tilt (HUT). In order to determine the effects of autonomic tone on HUT in children with CFS we performed measurements of HRV during HUT in 16 patients aged 11-19 with CFS.

Data were compared to 26 patients evaluated for syncope and with 13 normal control subjects. After 30 minutes supine, patients were tilted to 80 degrees for 40 minutes or until syncope occurred. Time domain indices included RR interval, SDNN, RMSSD, and pNN50. An autoregressive model was used to calculate power spectra. LFP (.04-.15 Hz), HFP (.15-.40Hz), and TP (.01-.40Hz). Data were obtained supine (baseline) and after HUT.

Thirteen CFS patients fainted (CFS+, 5/13 pure vasodepressor syncope) and three patients did not (CFS-). Sixteen syncope patients fainted (S+, all mixed vasodepressor-cardioinhibitory) and 10 did not (S-). Four control patients fainted (Control+, all mixed vasodepressor-cardioinhibitory) and nine did not (Control-). Baseline indices of HRV were not different between Control+ and S+, and between Control- and S-, but were depressed in S+ compared to S-. HRV indices were strikingly decreased in CFS patients compared to all other groups.

With tilt, SDNN, RMSSD, and pNN50 and spectral indices decreased in all groups, remaining much depressed in CFS compared to S or control subjects. With HUT, sympathovagal indices (LFP/HFP, nLFP, and nHFP) were relatively unchanged in CFS, which contrasts with the increase in nLFP with HUT in all other groups. With syncope RMSSD, SDNN, LFP, TP, and HFP increased in S+ (and Control+), suggesting enhanced vagal heart rate regulation. These increases were not observed in CFS+ patients.

CFS is associated with NMH during HUT in children. All indices of HRV are markedly depressed in CFS patients, even when compared with already low HRV in S+ or Control+ patients. Sympathovagal balance does not shift toward enhanced sympathetic modulation of heart rate with HUT and there is blunting in the overall HRV response with syncope during HUT. Taken together these data may indicate autonomic impairment in patients with CFS.

 

Source: Stewart J, Weldon A, Arlievsky N, Li K, Munoz J. Neurally mediated hypotension and autonomic dysfunction measured by heart rate variability during head-up tilt testing in children with chronic fatigue syndrome. Clin Auton Res. 1998 Aug;8(4):221-30. http://www.ncbi.nlm.nih.gov/pubmed/9791743