Reductions in Cerebral Blood Flow Can Be Provoked by Sitting in Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Why the Psychosomatic View on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Is Inconsistent with Current Evidence and Harmful to Patients

Since 1969, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) has been classified as a neurological disease in the International Classification of Diseases by the World Health Organization. Although numerous studies over time have uncovered organic abnormalities in patients with ME/CFS, and the majority of researchers to date classify the disease as organic, many physicians still believe that ME/CFS is a psychosomatic illness. In this article, we show how detrimental this belief is to the care and well-being of affected patients and, as a consequence, how important the education of physicians and the public is to stop misdiagnosis, mistreatment, and stigmatization on the grounds of incorrect psychosomatic attributions about the etiology and clinical course of ME/CFS.

Worsening Symptoms Is Associated with Larger Cerebral Blood Flow Abnormalities during Tilt-Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Background and Objectives: During tilt testing, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients experience an abnormal reduction in cerebral blood flow (CBF). The relationship between this CBF reduction and symptom severity has not been examined in detail. Our hypothesis was that ME/CFS severity is related to the degree of the CBF reduction during tilt testing. Materials and Methods: First, from our database, we selected ME/CFS patients who had undergone assessments of ME/CFS symptomatology and tilt tests on the same day, one at the first visit and the second during a follow-up. The change in symptomatology was related to the change in CBF during the tilt test. Second, we combined the data of two previously published studies (n = 219), where disease severity as defined by the 2011 international consensus criteria (ICC) was available but not published. Results: 71 patients were retested because of worsening symptoms. The ICC disease severity distribution (mild-moderate-severe) changed from 51/45/4% at visit-1 to 1/72/27% at follow-up (p < 0.0001). The %CBF reduction changed from initially 19% to 31% at follow-up (p < 0.0001). Of 39 patients with stable disease, the severity distribution was similar at visit-1 (36/51/13%) and at follow-up (33/49/18%), p = ns. The %CBF reduction remained unchanged: both 24%, p = ns. The combined data of the two previously published studies showed that patients with mild, moderate, and severe disease had %CBF reductions of 25, 29, and 33%, respectively (p < 0.0001). Conclusions: Disease severity and %CBF reduction during tilt testing are highly associated in ME/CFS: a more severe disease is related to a larger %CBF reduction. The data suggest a causal relationship where a larger CBF reduction leads to worsening symptoms.

Influence of end-tidal CO2 on cerebral blood flow during orthostatic stress in controls and adults with myalgic encephalomyelitis/chronic fatigue syndrome

Brain perfusion is sensitive to changes in CO2 levels (CO2 reactivity). Previously, we showed a pathological cerebral blood flow (CBF) reduction in the majority of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients during orthostatic stress. Limited data are available on the relation between CO2 and CBF changes in ME/CFS patients. Therefore, we studied this relation between ME/CFS patients and healthy controls (HC) during tilt testing. In this retrospective study, supine and end-tilt CBF, as measured by extracranial Doppler flow, were compared with PET CO2 data in female patients either with a normal heart rate and blood pressure (HR/BP) response or with postural orthostatic tachycardia syndrome (POTS), and in HC. Five hundred thirty-five female ME/CFS patients and 34 HC were included. Both in supine position and at end-tilt, there was a significant relation between CBF and PET CO2 in patients (p < 0.0001), without differences between patients with a normal HR/BP response and with POTS. The relations between the %CBF change and the PET CO2 reduction were both significant in patients and HC (p < 0.0001 and p = 0.0012, respectively). In a multiple regression analysis, the patient/HC status and PET CO2 predicted CBF. The contribution of the PET CO2 to CBF changes was limited, with low adjusted R2 values. In female ME/CFS patients, CO2 reactivity, as measured during orthostatic stress testing, is similar to that of HC and is independent of the type of hemodynamic abnormality. However, the influence of CO2 changes on CBF changes is modest in female ME/CFS patients.

Cardiovascular and haematological pathology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): A role for viruses

ME/CFS is a debilitating chronic condition that often develops after viral or bacterial infection. Insight from the study of Long COVID/Post Acute Sequelae of COVID-19 (PASC), the post-viral syndrome associated with SARS-CoV-2 infection, might prove to be useful for understanding pathophysiological mechanisms of ME/CFS. Disease presentation is similar between the two conditions, and a subset of Long COVID patients meet the diagnostic criteria for ME/CFS. Since Long COVID is characterized by significant vascular pathology - including endothelial dysfunction, coagulopathy, and vascular dysregulation - the question of whether or not the same biological abnormalities are of significance in ME/CFS arises. Cardiac abnormalities have for a while now been documented in ME/CFS cohorts, with recent studies demonstrating major deficits in cerebral blood flow, and hence vascular dysregulation. A growing body of research is demonstrating that ME/CFS is accompanied by platelet hyperactivation, anomalous clotting, a procoagulant phenotype, and endothelial dysfunction. Endothelial damage and dysregulated clotting can impair substance exchange between blood and tissues, and result in hypoperfusion, which may contribute to the manifestation of certain ME/CFS symptoms. Here we review the ME/CFS literature to summarize cardiovascular and haematological findings documented in patients with the condition, and, in this context, briefly discuss the potential role of previously-implicated pathogens. Overall, cardiac and haematological abnormalities are present within ME/CFS cohorts. While atherosclerotic heart disease is not significantly associated with ME/CFS, suboptimal cardiovascular function defined by reduced cardiac output, impaired cerebral blood flow, and vascular dysregulation are, and these abnormalities do not appear to be influenced by deconditioning. Rather, these cardiac abnormalities may result from dysfunction in the (autonomic) nervous system. Plenty of recently published studies are demonstrating significant platelet hyperactivity and endothelial dysfunction in ME/CFS, as well as anomalous clotting processes. It is of particular importance to determine to what extent these cardiovascular and haematological abnormalities contribute to symptom severity, and if these two systems can be targeted for therapeutic purposes. Viral reservoirs of herpesviruses exist in ME/CFS, and most likely contribute to cardiovascular and haematological dysfunction directly or indirectly. This review highlights the potential of studying cardiac functioning, the vasculature, and coagulation system in ME/CFS.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Comorbidities: Linked by Vascular Pathomechanisms and Vasoactive Mediators?

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is often associated with various other syndromes or conditions including mast cell activation (MCA), dysmenorrhea and endometriosis, postural tachycardia (POTS) and small fiber neuropathy (SFN). The causes of these syndromes and the reason for their frequent association are not yet fully understood. We previously published a comprehensive hypothesis of the ME/CFS pathophysiology that explains the majority of symptoms, findings and chronicity of the disease. We wondered whether some of the identified key pathomechanisms in ME/CFS are also operative in MCA, endometriosis and dysmenorrhea, POTS, decreased cerebral blood flow and SFN, and possibly may provide clues on their causes and frequent co-occurrence. Our analysis indeed provides strong arguments in favor of this assumption, and we conclude that the main pathomechanisms responsible for this association are excessive generation and spillover into the systemic circulation of inflammatory and vasoactive tissue mediators, dysfunctional β2AdR, and the mutual triggering of symptomatology and disease initiation. Overall, vascular dysfunction appears to be a strong common denominator in these linkages.

Long COVID: pathophysiological factors and abnormalities of coagulation

Acute COVID-19 infection is followed by prolonged symptoms in approximately one in ten cases: known as Long COVID. The disease affects ~65 million individuals worldwide. Many pathophysiological processes appear to underlie Long COVID, including viral factors (persistence, reactivation, and bacteriophagic action of SARS CoV-2); host factors (chronic inflammation, metabolic and endocrine dysregulation, immune dysregulation, and autoimmunity); and downstream impacts (tissue damage from the initial infection, tissue hypoxia, host dysbiosis, and autonomic nervous system dysfunction). These mechanisms culminate in the long-term persistence of the disorder characterized by a thrombotic endothelialitis, endothelial inflammation, hyperactivated platelets, and fibrinaloid microclots. These abnormalities of blood vessels and coagulation affect every organ system and represent a unifying pathway for the various symptoms of Long COVID.

Self-reported symptom burden in postural orthostatic tachycardia syndrome (POTS): A narrative review of observational and interventional studies

BACKGROUND AND OBJECTIVE

Postural Orthostatic Tachycardia Syndrome (POTS) is a chronic health condition affecting mostly women of childbearing age, and significantly impacting their health and quality of life. It is currently poorly understood with no approved licensed treatments. The aim of this systematic review was to contextualize the symptom burden of POTS, and review factors associated with this burden that may guide future treatments. The specific questions were (1) How does symptom burden in POTS compare to the burden in other long term conditions (LTCs), (2) Which factors are associated with POTS symptom burden, and (3) Which interventions show promise in reducing symptom burden in POTS.

DATABASES AND DATA TREATMENT

Electronic databases (CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science, APA PsycArticles, OpenGrey) were searched from inception to January 2022 for observational studies reporting on the association between any biological, psychological or social factors and symptom burden, and randomized controlled trials reporting on interventions for symptom burden in adults with POTS. Two reviewers independently conducted eligibility screening, data extraction and quality assessment. A narrative synthesis was undertaken.

RESULTS/CONCLUSION

5159 entries were screened for eligibility. Twenty-nine studies were included (1372 participants with POTS of a total sample size of 2314, 17 High-, 12 Medium-quality), seventeen were observational and twelve were randomized controlled experimental and intervention trials. Overall methodological quality of the evidence was medium-high but heterogeneity was high and sample sizes modest, allowing moderately robust conclusions. Orthostatic symptom burden was higher in POTS than other LTCs. Serum activity against adrenergic α1 receptors, physical functioning, depression, catastrophizing, prolonged cognitive stress testing and anxiety were significantly associated with symptom burden in medium-high quality studies. Preliminary medium-high quality evidence from predominantly proof-of-concept (n = 11) studies and one 3-month 2 × 2 factorial design trial suggest that compression garments, propranolol, pyridostigmine, desmopressin, and bisoprolol may hold promise in reducing symptom burden. Directions for future research include investigating associated factors over time, the development of complex interventions which address both biological and psychosocial factors associated with symptom burden, and effectiveness trials of these interventions.

SIGNIFICANCE

POTS symptom burden is high, particularly in relation to orthostatic intolerance when compared to other long-term conditions (LTCs). Despite this burden, there are no effectiveness randomized controlled trials of treatment to reduce symptoms in POTS. This review provides a starting point to understanding researched biological and psychosocial factors associated with this burden. There was however inconsistency in the measurement of symptom burden, lowering the confidence of cross-study inferences. A coherent definition of POTS symptom range, severity and impact along with a validated and reliable POTS-specific instrument is currently lacking. A standardized questionnaire to assess POTS symptom burden as a core outcome measure will help clarify future research and clinical practice.

Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect?

Following COVID-19 infection, a substantial proportion of patients suffer from persistent symptoms known as Long COVID. Among the main symptoms are fatigue, cognitive dysfunction, muscle weakness and orthostatic intolerance (OI). These symptoms also occur in myalgic encephalomyelitis/chronic fatigue (ME/CFS). OI is highly prevalent in ME/CFS and develops early during or after acute COVID-19 infection. The causes for OI are unknown and autonomic dysfunction is hypothetically assumed to be the primary cause, presumably as a consequence of neuroinflammation. Here, we propose an alternative, primary vascular mechanism as the underlying cause of OI in Long COVID. We assume that the capacitance vessel system, which plays a key role in physiologic orthostatic regulation, becomes dysfunctional due to a disturbance of the microvessels and the vasa vasorum, which supply large parts of the wall of those large vessels. We assume that the known microcirculatory disturbance found after COVID-19 infection, resulting from endothelial dysfunction, microthrombus formation and rheological disturbances of blood cells (altered deformability), also affects the vasa vasorum to impair the function of the capacitance vessels. In an attempt to compensate for the vascular deficit, sympathetic activity overshoots to further worsen OI, resulting in a vicious circle that maintains OI. The resulting orthostatic stress, in turn, plays a key role in autonomic dysfunction and the pathophysiology of ME/CFS.

Evidence base of economic evaluations of workplace-based interventions reducing occupational sitting time: an integrative review

OBJECTIVE

To review the evidence on the economic evaluations of workplace-based interventions that are designed to reduce prolonged periods of occupational sitting.

DESIGN

An integrative review.

DATA SOURCES

The search was conducted in 11 databases, including PubMed, Scopus, PsychINFO, NHS-EED, Cumulative Index to Nursing and Allied Health Literature (CINAHL), ProQuest, Cochrane library, Sportdiscus, Research Paper in Economics (RePeC), the International Health Economic Association (IHEA) and EconLit. The databases were searched for articles published from inception to January 2022. Subsequent citation searches were also conducted in Google Scholar. The items of the Consensus Health Economic Criteria (CHEC) checklist were used for quality appraisal of the included studies.

RESULTS

This review included five randomised control trails, including 757 office-based workers in high-income countries. The median quality appraisal score based on the CHEC items was 14 points (a range of 9-18). The mean duration of interventions was 33 weeks (a range of 4-52 weeks). Overall, the studies reported economic benefit when implemented to reduce occupational sitting time but no effect on absenteeism. From the societal perspective, the interventions (eg, the use of a sit-stand desk) were cost-effective.

CONCLUSION

The economic impact of workplace interventions implemented to reduce occupational sitting time is evident; however, the existing evidence is limited, which precludes strong conclusions. Cost-effectiveness is not often evaluated in the studies exploring workplace interventions that address occupational sitting time. Workplace interventions are still in the development and testing phase; thus, the challenge for future studies is to include economic evaluation of interventions addressing sedentary behaviour in workplaces.

PROSPERO REGISTRATION NUMBER

CRD42021226275.

A Natural History of Disease Framework for Improving the Prevention, Management, and Research on Post-viral Fatigue Syndrome and Other Forms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

We propose a framework for the treatment, rehabilitation, and research into Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) using a natural history of disease approach to outline the distinct disease stages, with an emphasis on cases following infection to provide insights into prevention. Moving away from the method of subtyping patients based on the various phenotypic presentations and instead reframing along the lines of disease progression could help with defining the distinct stages of disease, each of which would benefit from large prospective cohort studies to accurately describe the pathological mechanisms taking place therein. With a better understanding of these mechanisms, management and research can be tailored specifically for each disease stage. Pre-disease and early disease stages call for management strategies that may decrease the risk of long-term morbidity, by focusing on avoidance of further insults, adequate rest to enable recovery, and pacing of activities. Later disease stages require a more holistic and tailored management approach, with treatment-as this becomes available-targeting the alleviation of symptoms and multi-systemic dysfunction. More stringent and standardised use of case definitions in research is critical to improve generalisability of results and to create the strong evidence-based policies for management that are currently lacking in ME/CFS.

Psychogenic Pseudosyncope: Real or Imaginary? Results from a Case-Control Study in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Patients

Background and objectives: Orthostatic intolerance (OI) is a clinical condition in which symptoms worsen upon assuming and maintaining upright posture and are ameliorated by recumbency. OI has a high prevalence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Exact numbers on syncopal spells especially if they are on a weekly or even daily basis are not described. Although not a frequent phenomenon, this symptomatology is of very high burden to the patient if present. To explore whether patients with very frequent (pre)syncope spells diagnosed elsewhere with conversion or psychogenic pseudosyncope (PPS) might have another explanation of their fainting spells than behavioral psychiatric disorders, we performed a case-control study comparing ME/CFS patients with and without PPS spells. Methods and results: We performed a case-control study in 30 ME/CFS patients diagnosed elsewhere with PPS and compared them with 30 control ME/CFS patients without syncopal spells. Cases were gender, age and ME/CFS disease duration matched. Each underwent a tilt test with extracranial Doppler measurements for cerebral blood flow (CBF). ME/CFS cases with PPS had a significant larger CBF reduction at end tilt than controls: 39 (6)% vs. 25 (4)%; (p < 0.0001). Cases had more severe disease compared with controls (chi-square p < 0.01 and had a p = 0.01) for more postural orthostatic tachycardia syndrome in cases compared with controls. P_ETCO₂ end-tilt differed also, but the magnitude of difference was smaller than compared with the CBF reduction: there were no differences in heart rate and blood pressure at either end-tilt testing period. Compared with the test with the stockings off, the mean percentage reduction in cardiac output during the test with compression stockings on was lower, 25 (5) mmHg versus 29 (4) mmHg (p < 0.005). Conclusions: This study demonstrates that in ME/CFS patients suspected of having PPS, or conversion, CBF measurements end-tilt show a large decline compared with a control group of ME/CFS patients. Therefore, hypoperfusion offers an explanation of the orthostatic intolerance and syncopal spells in these patients, where it is clear that origin might not be behavioral or psychogenic, but have a clear somatic pathophysiologic background.

Orthostatic Challenge Causes Distinctive Symptomatic, Hemodynamic and Cognitive Responses in Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Background

Some patients with acute COVID-19 are left with persistent, debilitating fatigue, cognitive impairment ("brain fog"), orthostatic intolerance (OI) and other symptoms ("Long COVID"). Many of the symptoms are like those of other post-infectious fatigue syndromes and may meet criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Common diagnostic laboratory tests are often unrevealing.

Methods

We evaluated whether a simple, standardized, office-based test of OI, the 10-min NASA Lean Test (NLT), would aggravate symptoms and produce objective hemodynamic and cognitive abnormalities, the latter being evaluated by a simple smart phone-based app.

Participants

People with Long COVID (N = 42), ME/CFS (N = 26) and healthy control subjects (N = 20) were studied just before, during, immediately after, 2 and 7 days following completion of the NLT.

Results

The NLT provoked a worsening of symptoms in the two patient groups but not in healthy control subjects, and the severity of all symptoms was similar and significantly worse in the two patient groups than in the control subjects (p < 0.001). In the two patient groups, particularly those with Long COVID, the NLT provoked a marked and progressive narrowing in the pulse pressure. All three cognitive measures of reaction time worsened in the two patient groups immediately following the NLT, compared to the healthy control subjects, particularly in the Procedural Reaction Time (p < 0.01).

Conclusions

A test of orthostatic stress easily performed in an office setting reveals different symptomatic, hemodynamic and cognitive abnormalities in people with Long COVID and ME/CFS, compared to healthy control subjects. Thus, an orthostatic challenge easily performed in an office setting, and the use of a smart phone app to assess cognition, can provide objective confirmation of the orthostatic intolerance and brain fog reported by patients with Long COVID and ME/CFS.

Compression Stockings Improve Cardiac Output and Cerebral Blood Flow during Tilt Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Patients: A Randomized Crossover Trial

Background and Objectives: Orthostatic intolerance (OI) is a clinical condition in which symptoms worsen upon assuming and maintaining upright posture and are ameliorated by recumbency. OI has a high prevalence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Limited data are available to guide the treatment of OI in ME/CFS patients. We and others have previously described patient-reported subjective improvement in symptoms using compression stockings. We hypothesized that these subjective reports would be accompanied by objective hemodynamic improvements. Materials and Methods: We performed a randomized crossover trial in 16 ME/CFS patients. Each underwent two 15-min head-up tilt table tests, one with and one without wearing knee-high compression stockings that provided 20–25 mm Hg compression. The order of the tests was randomized. We measured heart rate and blood pressure as well as cardiac output and cerebral blood flow (CBF) using extracranial Doppler of the internal carotid and vertebral arteries. Results: There were no differences in supine measurements between the 2 baseline measurements. There were no differences in heart rate and blood pressure at either end-tilt testing period. Compared to the test with the stockings off, the mean percentage reduction in cardiac output during the test with compression stockings on was lower, 15 (4)% versus 27 (6)% (p < 0.0001), as was the mean percentage CBF reduction, 14 (4)% versus 25 (5)% (p < 0.0001). Conclusion: In ME/CFS patients with orthostatic intolerance symptoms, cardiac output and CBF are significantly reduced during a tilt test. These abnormalities were present without demonstrable heart rate and blood pressure changes and were ameliorated by the use of compression stockings.

An attempt to explain the neurological symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

There is accumulating evidence of endothelial dysfunction, muscle and cerebral hypoperfusion in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). In this paper we deduce the pathomechanisms resulting in central nervous pathology and the myriad of neurocognitive symptoms. We outline tentative mechanisms of impaired cerebral blood flow, increase in intracranial pressure and central adrenergic hyperactivity and how they can well explain the key symptoms of cognitive impairment, brain fog, headache, hypersensitivity, sleep disturbances and dysautonomia.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Essentials of Diagnosis and Management

Despite myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) affecting millions of people worldwide, many clinicians lack the knowledge to appropriately diagnose or manage ME/CFS. Unfortunately, clinical guidance has been scarce, obsolete, or potentially harmful. Consequently, up to 91% of patients in the United States remain undiagnosed, and those diagnosed often receive inappropriate treatment. These problems are of increasing importance because after acute COVID-19, a significant percentage of people remain ill for many months with an illness similar to ME/CFS. In 2015, the US National Academy of Medicine published new evidence-based clinical diagnostic criteria that have been adopted by the US Centers for Disease Control and Prevention. Furthermore, the United States and other governments as well as major health care organizations have recently withdrawn graded exercise and cognitive-behavioral therapy as the treatment of choice for patients with ME/CFS. Recently, 21 clinicians specializing in ME/CFS convened to discuss best clinical practices for adults affected by ME/CFS. This article summarizes their top recommendations for generalist and specialist health care providers based on recent scientific progress and decades of clinical experience. There are many steps that clinicians can take to improve the health, function, and quality of life of those with ME/CFS, including those in whom ME/CFS develops after COVID-19. Patients with a lingering illness that follows acute COVID-19 who do not fully meet criteria for ME/CFS may also benefit from these approaches.

Cerebral blood flow remains reduced after tilt testing in myalgic encephalomyelitis/chronic fatigue syndrome patients

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Cerebral blood flow in ME/CFS patients remains abnormal 5 min post-tilt test.

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Post cerebral blood flow abnormalities do not depend on hemodynamic results and on end-tidal carbon dioxide pressures during the tilt-test.

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Post cerebral blood flow abnormalities are most severe in more severely diseased ME/CFS patients.

Objective

Orthostatic symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may be caused by an abnormal reduction in cerebral blood flow. An abnormal cerebral blood flow reduction was shown in previous studies, without information on the recovery pace of cerebral blood flow. This study examined the prevalence and risk factors for delayed recovery of cerebral blood flow in ME/CFS patients.

Methods

60 ME/CFS adults were studied: 30 patients had a normal heart rate and blood pressure response during the tilt test, 4 developed delayed orthostatic hypotension, and 26 developed postural orthostatic tachycardia syndrome (POTS) during the tilt. Cerebral blood flow measurements, using extracranial Doppler, were made in the supine position pre-tilt, at end-tilt, and in the supine position at 5 min post-tilt. Also, cardiac index measurements were performed, using suprasternal Doppler imaging, as well as end-tidal PCO2 measurements. The change in cerebral blood flow from supine to end-tilt was expressed as a percent reduction with mean and (SD). Disease severity was scored as mild (approximately 50% reduction in activity), moderate (mostly housebound), or severe (mostly bedbound).

Results

End-tilt cerebral blood flow reduction was −29 (6)%, improving to −16 (7)% at post-tilt. No differences in either end-tilt or post-tilt measurements were found when patients with a normal heart rate and blood pressure were compared to those with POTS, or between patients with normocapnia (end-tidal PCO2 ≥ 30 mmHg) versus hypocapnia (end-tidal PCO2 < 30 mmHg) at end-tilt. A significant difference was found in the degree of abnormal cerebral blood flow reduction in the supine post-test in mild, moderate, and severe ME/CFS: mild: cerebral blood flow: −7 (2)%, moderate: −16 (3)%, and severe :-25 (4)% (p all < 0.0001). Cardiac index declined significantly during the tilt test in all 3 severity groups, with no significant differences between the groups. In the supine post-test cardiac index returned to normal in all patients.

Conclusions

During tilt testing, extracranial Doppler measurements show that cerebral blood flow is reduced in ME/CFS patients and recovery to normal supine values is incomplete, despite cardiac index returning to pre-tilt values. The delayed recovery of cerebral blood flow was independent of the hemodynamic findings of the tilt test (normal heart rate and blood pressure response, POTS, or delayed orthostatic hypotension), or the presence/absence of hypocapnia, and was only related to clinical ME/CFS severity grading. We observed a significantly slower recovery in cerebral blood flow in the most severely ill ME/CFS patients.

Significance

The finding that orthostatic stress elicits a post-stress cerebral blood flow reduction and that disease severity greatly influences the cerebral blood flow reduction may have implications on the advice of energy management after a stressor and on the advice of lying down after a stressor in these ME/CFS patients.

Caring for the Patient with Severe or Very Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) can cause a wide range of severity and functional impairment, leaving some patients able to work while others are homebound or bedbound. The most severely ill patients may need total care. Yet, patients with severe or very severe ME/CFS struggle to receive appropriate medical care because they cannot travel to doctors’ offices and their doctors lack accurate information about the nature of this disease and how to diagnose and manage it. Recently published clinical guidance provides updated information about ME/CFS but advice on caring for the severely ill is limited. This article is intended to fill that gap. Based on published clinical guidance and clinical experience, we describe the clinical presentation of severe ME/CFS and provide patient-centered recommendations on diagnosis, assessment and approaches to treatment and management. We also provide suggestions to support the busy provider in caring for these patients by leveraging partnerships with the patient, their caregivers, and other providers and by using technology such as telemedicine. Combined with compassion, humility, and respect for the patient’s experience, such approaches can enable the primary care provider and other healthcare professionals to provide the care these patients require and deserve.

Comparison of the Active Sitting Test and Head-Up Tilt Test for Diagnosis of Postural Tachycardia Syndrome in Children and Adolescents

Objectives: We aimed to compare the hemodynamic responses to the active sitting test with the passive head-up tilt test (HUTT) in children and adolescents with postural tachycardia syndrome (POTS). We hypothesized that sitting tachycardia was also present in POTS patients during sitting. Materials and methods: We tested 30 POTS patients and 31 control subjects (mean age = 12 years, range = 9-16 years) who underwent both active sitting test and HUTT successively. We measured the heart rate (HR) and blood pressure (BP) during each test. Results: For both POTS patients and control subjects, the HUTT produced significantly larger HR and BP increases from 3 to 10 min of postural change than did the sitting test. Moreover, POTS patients with excessive orthostatic tachycardia during the HUTT also had significantly larger increases in HR at all test intervals during the sitting test than did the control subjects. A maximum increase in HR ≥ 22 bpm within 10 min of the sitting test was likely suggested to predict orthostatic tachycardia, yielding a sensitivity and specificity of 83.3 and 83.9%, respectively. Only six of 30 POTS patients (20%) reached the 40-bpm criterion during the sitting test, and no one complained of sitting intolerance symptoms. Conclusions: We have shown that POTS patients also have sitting tachycardia when changing from a supine position to a sitting position. We believe that the active sitting test is a reasonable alternative maneuver in assessing POTS in population groups that cannot tolerate the standing test or HUTT.

Pathophysiology of skeletal muscle disturbances in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Chronic Fatigue Syndrome or Myalgic Encephaloymelitis (ME/CFS) is a frequent debilitating disease with an enigmatic etiology. The finding of autoantibodies against ß2-adrenergic receptors (ß2AdR) prompted us to hypothesize that ß2AdR dysfunction is of critical importance in the pathophysiology of ME/CFS. Our hypothesis published previously considers ME/CFS as a disease caused by a dysfunctional autonomic nervous system (ANS) system: sympathetic overactivity in the presence of vascular dysregulation by ß2AdR dysfunction causes predominance of vasoconstrictor influences in brain and skeletal muscles, which in the latter is opposed by the metabolically stimulated release of endogenous vasodilators (functional sympatholysis). An enigmatic bioenergetic disturbance in skeletal muscle strongly contributes to this release. Excessive generation of these vasodilators with algesic properties and spillover into the systemic circulation could explain hypovolemia, suppression of renin (paradoxon) and the enigmatic symptoms. In this hypothesis paper the mechanisms underlying the energetic disturbance in muscles will be explained and merged with the first hypothesis. The key information is that ß2AdR also stimulates the Na+/K+-ATPase in skeletal muscles. Appropriate muscular perfusion as well as function of the Na+/K+-ATPase determine muscle fatigability. We presume that dysfunction of the ß2AdR also leads to an insufficient stimulation of the Na+/K+-ATPase causing sodium overload which reverses the transport direction of the sodium-calcium exchanger (NCX) to import calcium instead of exporting it as is also known from the ischemia-reperfusion paradigm. The ensuing calcium overload affects the mitochondria, cytoplasmatic metabolism and the endothelium which further worsens the energetic situation (vicious circle) to explain postexertional malaise, exercise intolerance and chronification. Reduced Na+/K+-ATPase activity is not the only cause for cellular sodium loading. In poor energetic situations increased proton production raises intracellular sodium via sodium-proton-exchanger subtype-1 (NHE1), the most important proton-extruder in skeletal muscle. Finally, sodium overload is due to diminished sodium outward transport and enhanced cellular sodium loading. As soon as this disturbance would have occurred in a severe manner the threshold for re-induction would be strongly lowered, mainly due to an upregulated NHE1, so that it could repeat at low levels of exercise, even by activities of everyday life, re-inducing mitochondrial, metabolic and vascular dysfunction to perpetuate the disease.