[Post-COVID syndrome with fatigue and exercise intolerance: myalgic encephalomyelitis/chronic fatigue syndrome]

Abstract

BACKGROUND: A sizable part of post-COVID syndrome meets the diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). A doubling of  cases of ME/CFS within the next years is therefore projected. OBJECTIVES:  Presentation of the current state of knowledge on ME/CFS. MATERIALS AND METHODS:  Unsystematic review of the literature and of own contributions in research and  patient care. RESULTS AND CONCLUSIONS: ME/CFS is a neuroimmunological disease,  mostly infection-induced, usually persisting throughout life. Clinically it is  characterized by fatigue lasting at least 6 months and the defining core feature  of exercise intolerance (post-exertional malaise, PEM). Exercise intolerance is  defined as a worsening of symptoms after (even mild) everyday exertion, which  usually begins after several hours or on the following day, is still noticeable  at least 14 h after exertion, and often lasts for several days (up to weeks or  longer). Furthermore, ME/CFS is characterized by pain, disturbances of sleep,  thinking and memory, and dysregulation of the circulatory, endocrine, and immune  systems. As a separate clinical entity, ME/CFS should be distinguished from  chronic fatigue, which occurs as a symptom of a range of very different diseases.  The diagnosis of ME/CFS is made clinically using established international  diagnostic criteria and requires careful stepwise diagnosis to exclude other  diagnoses. A causal therapy for ME/CFS has not been established; the focus is on  symptoms relief, treatment of the often accompanying orthostatic intolerance, and  assistance with anticipatory energy management (pacing).