Physiological assessment of orthostatic intolerance in chronic fatigue syndrome

Abstract:

Background: Orthostatic intolerance-OI is common in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-ME/CFS. We used a 10-min passive vertical lean test as orthostatic challenge-OC and measured changes in vitals and end tidal CO2 (eTCO2). An abnormal physiologic response to OC was identified in 60% of the 63 patients evaluated from one to three times over several years. Hypocapnia, either resting or induced by OC, was the most frequent abnormality, followed by postural orthostatic tachycardia.

Objective: Evaluate the physiologic response of patients with ME/CFS to a standardized OC.

Design: Respiratory and heart rate, blood pressure and eTCO2 were recorded twice at the end of 10-min supine rest and then every minute during the 10-min lean. Hypocapnia was eTCO2 ≤ 32 mmHg. Orthostatic tachycardia was heart rate increase ≥ 30 beats per minute compared with resting or ≥ 120 BPM. Orthostatic hypotension was decreased systolic pressure ≥ 20 mmHg from baseline. Tachypnea was respiratory rate of ≥ 20 breaths per minute-either supine or leaning. Questionnaire data on symptom severity, quality of life and mood were collected at visit #2.

Patients: 63 consecutive patients fulfilling the 1994 case definition for CFS underwent lean testing at first visit and then annually at visit 2 (n = 48) and 3 (n = 29).

Measures: Supine hypocapnia; orthostatic tachycardia, hypocapnia or hypotension.

Results: The majority of ME/CFS patients (60.3%, 38/63) had an abnormality detected during a lean test at any visit (51%, 50% and 45% at visits 1, 2 and 3, respectively). Hypocapnia at rest or induced by OC was more common and more likely to persist than postural orthostatic tachycardia. Anxiety scores did not differ between those with and without hypocapnia.

Conclusions: The 10-min lean test is useful in evaluation of OI in patients with ME/CFS. The most frequent abnormality, hypocapnia, would be missed without capnography.

Source: Natelson BH, Lin JS, Blate M, Khan S, Chen Y, Unger ER. Physiological assessment of orthostatic intolerance in chronic fatigue syndrome. J Transl Med. 2022 Feb 16;20(1):95. doi: 10.1186/s12967-022-03289-8. PMID: 35172863. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-022-03289-8 (Full study)

Use of Cardiopulmonary Stress Testing for Patients With Unexplained Dyspnea Post–Coronavirus Disease

Abstract:

Objectives: The authors used cardiopulmonary exercise testing (CPET) to define unexplained dyspnea in patients with post-acute sequelae of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (PASC). We assessed participants for criteria to diagnose myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Background: Approximately 20% of patients who recover from coronavirus disease (COVID) remain symptomatic. This syndrome is named PASC. Its etiology is unclear. Dyspnea is a frequent symptom.

Methods: The authors performed CPET and symptom assessment for ME/CFS in 41 patients with PASC 8.9 ± 3.3 months after COVID. All patients had normal pulmonary function tests, chest X-ray, and chest computed tomography scans. Peak oxygen consumption (peak VO2), slope of minute ventilation to CO2 production (VE/VCO2 slope), and end tidal pressure of CO2 (PetCO2) were measured. Ventilatory patterns were reviewed with dysfunctional breathing defined as rapid erratic breathing.

Results: Eighteen men and 23 women (average age: 45 ± 13 years) were studied. Left ventricular ejection fraction was 59% ± 9%. Peak VO2 averaged 20.3 ± 7 mL/kg/min (77% ± 21% predicted VO2). VE/VCO2 slope was 30 ± 7. PetCO2 at rest was 33.5 ± 4.5 mm Hg. Twenty-four patients (58.5%) had a peak VO2 <80% predicted. All patients with peak VO2 <80% had a circulatory limitation to exercise. Fifteen of 17 patients with normal peak VO2 had ventilatory abnormalities including peak respiratory rate >55 (n = 3) or dysfunctional breathing (n = 12). For the whole cohort, 88% of patients (n = 36) had ventilatory abnormalities with dysfunctional breathing (n = 26), increased VE/VCO2 (n = 17), and/or hypocapnia PetCO2 <35 (n = 25). Nineteen patients (46%) met criteria for ME/CFS.

Conclusions: Circulatory impairment, abnormal ventilatory pattern, and ME/CFS are common in patients with PASC. The dysfunctional breathing, resting hypocapnia, and ME/CFS may contribute to symptoms. CPET is a valuable tool to assess these patients.

Source: Mancini DM, Brunjes DL, Lala A, Trivieri MG, Contreras JP, Natelson BH. Use of Cardiopulmonary Stress Testing for Patients With Unexplained Dyspnea Post-Coronavirus Disease. JACC Heart Fail. 2021 Dec;9(12):927-937. doi: 10.1016/j.jchf.2021.10.002. PMID: 34857177; PMCID: PMC8629098. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8629098/ (Full text)

Use of Cardiopulmonary Stress Testing for Patients With Unexplained Dyspnea Post-Coronavirus Disease

Abstract:

Objectives: The authors used cardiopulmonary exercise testing (CPET) to define unexplained dyspnea in patients with post-acute sequelae of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (PASC). We assessed participants for criteria to diagnose myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Background: Approximately 20% of patients who recover from coronavirus disease (COVID) remain symptomatic. This syndrome is named PASC. Its etiology is unclear. Dyspnea is a frequent symptom.

Methods: The authors performed CPET and symptom assessment for ME/CFS in 41 patients with PASC 8.9 ± 3.3 months after COVID. All patients had normal pulmonary function tests, chest X-ray, and chest computed tomography scans. Peak oxygen consumption (peak VO2), slope of minute ventilation to CO2 production (VE/VCO2 slope), and end tidal pressure of CO2 (PetCO2) were measured. Ventilatory patterns were reviewed with dysfunctional breathing defined as rapid erratic breathing.

Results: Eighteen men and 23 women (average age: 45 ± 13 years) were studied. Left ventricular ejection fraction was 59% ± 9%. Peak VO2 averaged 20.3 ± 7 mL/kg/min (77% ± 21% predicted VO2). VE/VCO2 slope was 30 ± 7. PetCO2 at rest was 33.5 ± 4.5 mm Hg. Twenty-four patients (58.5%) had a peak VO2 <80% predicted. All patients with peak VO2 <80% had a circulatory limitation to exercise. Fifteen of 17 patients with normal peak VO2 had ventilatory abnormalities including peak respiratory rate >55 (n = 3) or dysfunctional breathing (n = 12). For the whole cohort, 88% of patients (n = 36) had ventilatory abnormalities with dysfunctional breathing (n = 26), increased VE/VCO2 (n = 17), and/or hypocapnia PetCO2 <35 (n = 25). Nineteen patients (46%) met criteria for ME/CFS.

Conclusions: Circulatory impairment, abnormal ventilatory pattern, and ME/CFS are common in patients with PASC. The dysfunctional breathing, resting hypocapnia, and ME/CFS may contribute to symptoms. CPET is a valuable tool to assess these patients.

Source: Mancini DM, Brunjes DL, Lala A, Trivieri MG, Contreras JP, Natelson BH. Use of Cardiopulmonary Stress Testing for Patients With Unexplained Dyspnea Post-Coronavirus Disease. JACC Heart Fail. 2021 Dec;9(12):927-937. doi: 10.1016/j.jchf.2021.10.002. PMID: 34857177.  https://pubmed.ncbi.nlm.nih.gov/34857177/

Chronic Fatigue Syndrome and Cardiovascular Disease: JACC State-of-the-Art Review

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medically unexplained illness characterized by severe fatigue limiting normal daily activities for at least 6 months accompanied by problems with unrefreshing sleep, exacerbation of symptoms following physical or mental efforts (postexertional malaise [PEM]), and either cognitive reports or physiological evidence of orthostatic intolerance in the form of either orthostatic tachycardia and/or hypocapnia.

Although rarely considered to have cardiac dysfunction, ME/CFS patients frequently have reduced stroke volume with a significant inverse relation between cardiac output and PEM severity. Magnetic resonance imaging of ME/CFS patients compared with normal control subjects found significantly reduced stroke, end-systolic, and end-diastolic volumes together with reduced end-diastolic wall mass. Another cardiovascular abnormality is reduced nocturnal blood pressure assessed by 24-hour monitoring. Autonomic dysfunction is also frequently observed with postural orthostatic tachycardia and/or hypocapnia. Two consecutive cardiopulmonary stress tests may provide metabolic data substantiating PEM.

Source: Natelson BH, Brunjes DL, Mancini D. Chronic Fatigue Syndrome and Cardiovascular Disease: JACC State-of-the-Art Review. J Am Coll Cardiol. 2021 Sep 7;78(10):1056-1067. doi: 10.1016/j.jacc.2021.06.045. PMID: 34474739. https://pubmed.ncbi.nlm.nih.gov/34474739/

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Essentials of diagnosis and management

Abstract:

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.
Source: Lucinda Bateman, MD, Alison C. Bested, MD, Hector F. Bonilla, MD, Ilene S. Ruhoy, MD, PhD, Maria A. Vera-Nunez, MD, MSBI, Brayden P. Yellman, MD et al. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Essentials of Diagnosis and Management. Mayo Clinic Proceedings. Open Access. Published:August 25, 2021DOI:https://doi.org/10.1016/j.mayocp.2021.07.004 https://www.mayoclinicproceedings.org/article/S0025-6196(21)00513-9/fulltext (Full text)

An analysis of 2‐day cardiopulmonary exercise testing to assess unexplained fatigue

Abstract:

Two consecutive maximal cardiopulmonary exercise tests (CPETs) performed 24 hr apart (2-day CPET protocol) are increasingly used to evaluate post-exertional malaise (PEM) and related disability among individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This protocol may extend to other fatiguing illnesses with similar characteristics to ME/CFS; however, 2-day CPET protocol reliability and minimum change required to be considered clinically meaningful (i.e., exceeding the standard error of the measure) are not well characterized. To address this gap, we evaluated the 2-day CPET protocol in Gulf War Illness (GWI) by quantifying repeatability of seven CPET parameters, establishing their thresholds of clinically significant change, and determining whether changes differed between veterans with GWI and controls.

Excluding those not attaining peak effort criteria (n = 15), we calculated intraclass correlation coefficients (ICCs), the smallest real difference (SRD%), and repeated measures analysis of variance (RM-ANOVA) at the ventilatory anaerobic threshold (VAT) and peak exercise in 15 veterans with GWI and eight controls. ICC values at peak ranged from moderate to excellent for veterans with GWI (mean [range]; 0.84 [0.65 – 0.92]) and were reduced at the VAT (0.68 [0.37 – 0.78]).

Across CPET variables, the SRD% at peak exercise for veterans with GWI (18.8 [8.8 – 28.8]) was generally lower than at the VAT (28.1 [9.5 – 34.8]). RM-ANOVAs did not detect any significant group-by-time interactions (all p > .05). The methods and findings reported here provide a framework for evaluating 2-day CPET reliability, and reinforce the importance of carefully considering measurement error in the population of interest when interpreting findings.

Source: Lindheimer JB, Alexander T, Qian W, et al. An analysis of 2-day cardiopulmonary exercise testing to assess unexplained fatigue. Physiol Rep. 2020;8(17):e14564. doi:10.14814/phy2.14564 (Full text) https://physoc.onlinelibrary.wiley.com/doi/full/10.14814/phy2.14564

The Effect of Comorbid Medical and Psychiatric Diagnoses on Chronic Fatigue Syndrome

Abstract:

OBJECTIVE: To determine if presence of co-existing medically unexplained syndromes or psychiatric diagnoses affect symptom frequency, severity or activity impairment in Chronic Fatigue Syndrome.

PATIENTS: Sequential Chronic Fatigue Syndrome patients presenting in one clinical practice.

DESIGN: Participants underwent a psychiatric diagnostic interview and were evaluated for fibromyalgia, irritable bowel syndrome and/or multiple chemical sensitivity.

RESULTS: Current and lifetime psychiatric diagnosis was common (68%) increasing mental fatigue/health but not other illness variables and not with diagnosis of other medically unexplained syndromes. 81% of patients had at least one of these conditions with about a third having all three co-existing syndromes. Psychiatric diagnosis was not associated with their diagnosis. Increasing the number of these unexplained conditions was associated with increasing impairment in physical function, pain and rates of being unable to work.

CONCLUSIONS: Patients with Chronic Fatigue Syndrome should be evaluated for current psychiatric conditions because of their impact on patient quality of life, but they do not act as a symptom multiplier for the illness. Other co-existing medically unexplained syndromes are more common than psychiatric co-morbidities in patients presenting for evaluation of medically unexplained fatigue and are also more associated with increased disability and the number and severity of symptoms.

Key Messages: When physicians see patients with medically unexplained fatigue, they often infer that this illness is due to an underlying psychiatric problem. This paper shows that the presence of co-existing psychiatric diagnoses does not impact on any aspect of the phenomenology of medically unexplained fatigue also known as chronic fatigue syndrome. Therefore, psychiatric status is not an important causal contributor to CFS. In contrast, the presence of other medically unexplained syndromes [irritable bowel syndrome; fibromyalgia and/or multiple chemical sensitivity] do impact on the illness such that the more of these that co-exist the more health-related burdens the patient has.

Source: Natelson BH, Lin JS, Lange G, Khan S, Stegner A, Unger ER. The Effect of Comorbid Medical and Psychiatric Diagnoses on Chronic Fatigue Syndrome. Ann Med. 2019 Oct 23:1-18. doi: 10.1080/07853890.2019.1683601. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31642345

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: Definitions, Similarities, and Differences

Abstract:

This commentary presents a simplified way of making the diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) using the 1994 Centers for Disease Control and Prevention case definition. The format used can easily be modified for other case definitions. The commentary then discusses whether ME/CFS is the same or a different illness from fibromyalgia.

Because overlap exists between the 2 syndromes, some investigators have posited that they are variants of the same illness. I have viewed this as an empirically testable hypothesis and have summoned considerable amounts of data that suggest that the 2 illnesses differ. Were differences to exist, that would suggest different pathophysiologic processes for each, leading to different treatments.

Copyright © 2019. Published by Elsevier Inc.

Source: Natelson BH. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: Definitions, Similarities, and Differences. Clin Ther .2019 Feb 19. pii: S0149-2918(19)30003-7. doi: 10.1016/j.clinthera.2018.12.016. [Epub ahead of print]  https://www.ncbi.nlm.nih.gov/pubmed/30795933

Balance deficits in Chronic Fatigue Syndrome with and without fibromyalgia

Abstract:

OBJECTIVE: Chronic Fatigue Syndrome (CFS) is a disorder of unknown etiology associated with debilitating fatigue. One symptom commonly reported is disequilibrium. The goal of this study was to determine if CFS patients demonstrated verified balance deficits and if this was effected by comorbid fibromyalgia (FM).

METHODS: Twenty-seven patients with CFS (12 with comorbid FM) and 22 age and gender matched controls performed posturography.

RESULTS: Balance scores were significantly correlated with physical functional status in the CFS group (R2 = 0.43, P < 0.001), which was not found for mental functional status (R2 = 0.06, P > 0.5). CFS patients (regardless of FM) had significantly higher anxiety subscale of the vertigo symptom scale scores. CFS patients, regardless of FM status, demonstrated significantly lower overall composite balance scores (Controls – 78.8±1.5; CFS – 69.0±1.4, P < 0.005) even when controlling for anxiety and also had worse preference scores, indicating they relied on visual information preferentially even when visual information was incorrect. Interestingly, the CFS+FM group, not CFS only, demonstrated significantly worse vestibular scores (Controls – 70.2±2.4; CFS only – 67.9±3.8; CFS with FM – 55.4±4.6, P = 0.013).

INTERPRETATION: The major findings are that poor balance may be associated with poorer self-reported physical health. In addition, CFS patients seemed to rely preferentially on visual inputs, regardless of whether it was correct. The finding that vestibular function may be impaired in patients with CFS+FM but not in those with CFS alone suggests that the pathophysiology of CFS+FM may differ as has been suggested by some.

Source: Serrador JM, Quigley K, Zhao C, Findley T, Natelson BH. Balance deficits in Chronic Fatigue Syndrome with and without fibromyalgia. NeuroRehabilitation. 2018;42(2):235-246. doi: 10.3233/NRE-172245.

Elevations of Ventricular Lactate Levels Occur in Both Chronic Fatigue Syndrome and Fibromyalgia

Abstract:

Background: Chronic fatigue syndrome (CFS) and fibromyalgia (FM) frequently have overlapping symptoms, leading to the suggestion that the same disease processes may underpin the two disorders – the unitary hypothesis. However, studies investigating the two disorders have reported substantial clinical and/or biological differences them, suggesting distinct pathophysiological underpinnings.

Purpose: The purpose of this study was to further add to the body of evidence favoring different disease processes in CFS and FM by comparing ventricular cerebrospinal fluid lactate levels among patients with CFS alone, FM alone, overlapping CFS and FM symptoms, and healthy control subjects.

Methods: Ventricular lactate was assessed in vivo with proton magnetic resonance spectroscopic imaging (1H MRSI) with the results normed across the 2 studies in which the data were collected.

Results: Mean CSF lactate levels in CFS, FM and CFS+FM did not differ among the three groups, but were all significantly higher than the mean values for control subjects.

Conclusion: While patients with CFS, FM and comorbid CFS and FM can be differentiated from healthy subjects based on measures of CFS lactate, this neuroimaging outcome measure is not a viable biomarker for differentiating CFS from FM or from patients in whom symptoms of the two disorders overlap.

Source: Natelson BH, Vu D, Coplan JD, Mao X, Blate M, Kang G, Soto E, Kapusuz T, Shungu DC. Elevations of Ventricular Lactate Levels Occur in Both Chronic Fatigue Syndrome and Fibromyalgia. Fatigue. 2017;5(1):15-20. doi: 10.1080/21641846.2017.1280114. Epub 2017 Feb 20.  https://www.ncbi.nlm.nih.gov/pubmed/29308330