Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms

Abstract

Although myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) are considered to be synonymous, the definitional criteria for ME and CFS define two distinct, partially overlapping, clinical entities. ME, whether defined by the original criteria or by the recently proposed criteria, is not equivalent to CFS, let alone a severe variant of incapacitating chronic fatigue. Distinctive features of ME are: muscle weakness and easy muscle fatigability, cognitive impairment, circulatory deficits, a marked variability of the symptoms in presence and severity, but above all, post-exertional "malaise": a (delayed) prolonged aggravation of symptoms after a minor exertion. In contrast, CFS is primarily defined by (unexplained) chronic fatigue, which should be accompanied by four out of a list of 8 symptoms, e.g., headaches. Due to the subjective nature of several symptoms of ME and CFS, researchers and clinicians have questioned the physiological origin of these symptoms and qualified ME and CFS as functional somatic syndromes. However, various characteristic symptoms, e.g., post-exertional "malaise" and muscle weakness, can be assessed objectively using well-accepted methods, e.g., cardiopulmonary exercise tests and cognitive tests. The objective measures acquired by these methods should be used to accurately diagnose patients, to evaluate the severity and impact of the illness objectively and to assess the positive and negative effects of proposed therapies impartially.

Replacing Myalgic Encephalomyelitis and Chronic Fatigue Syndrome with Systemic Exercise Intolerance Disease Is Not the Way forward

“…Considering the controversy with regard to the etiology and psychophysiology of ME and CFS [ 29 , 39 ] and the abstract and subjective nature of typical symptoms of ME and CFS, a diagnosis based upon self-reported measures is not adequate. As far is possible, objective methods should be employed to assess the symptoms and disability [ 35 ]. Characteristic symptoms, e.g., “fatigue,” long-lasting post-exertional weakness, cognitive impairment, post-exertional malaise (the negative effect of exercise on cognitive and physical performance levels) and visual problems can be “objectified” by using well-accepted methods, e.g., (repeated) cardiopulmonary exercise tests, neuropsychological tests (before and after an exercise test), (repeated) muscle power strength and endurance tests, tilt-table tests, and visual field tests.…”

“…As the IOM report [ 14 ] states: “(Twisk) asserts that (…) objective assessment must address the unique symptoms in accordance with the diagnosis, whether it be ME or CFS” [ 34 ]. Various symptoms of ME and CFS can be assessed objectively, e.g., cognitive impairment, (post-exertional) muscle weakness, post-exertional “malaise” (long-lasting negative impact of exertion on symptoms) and orthostatic intolerance [ 35 ].…”

Myalgic Encephalomyelitis, Chronic Fatigue Syndrome, and Systemic Exertion Intolerance Disease: Three Distinct Clinical Entities

“…This results in missed diagnoses and misdiagnoses, as illustrated by a study of Jason et al [23], which observed that a substantial subgroup of patients with other medical diseases, such as MS, lupus, and major depressive disorders, also qualify as being SEID [3] patients. For that reason, and because ME [1], CFS [2], and SEID [3] are considered to be controversial disorders, characteristic symptoms of ME [1], CFS [2], and SEID [3] should be assessed objectively [25], both in research projects as well as in clinical practice.…”

Dutch Health Council Advisory Report on Myalgic Encephalomyelitis and Chronic Fatigue Syndrome: Taking the Wrong Turn

“…The existence and magnitude of various characteristic symptoms of ME [2,3,4] and CFS [5] can be assessed objectively [41,42]. For example, loss of muscle power and prolonged muscle weakness after physical exertion [43] can be established by measuring muscle power during repeated contractions using dynamometers with 24 h rest in-between.…”