BACKGROUND: Myalgic encephalitis or chronic fatigue syndrome (ME/CFS) has again come into focus as a result of coronavirus disease 2019 (COVID-19). Fundamentally problematic is the fact that ME/CFS is considered a separate entity; however, extreme fatigue is also a common symptom of an underlying disease. Our article aims to increase the acceptance of ME/CFS and extreme fatigue facing a symptomatology that is not fully understood, and to highlight the need for research, orientation for physicians, and counselling services for patients.
MATERIALS AND METHODS: Orientative research by focused information gathering.
RESULTS: In various research projects, the hypothesis of post-infectious ME/CFS as an autoimmune disease could be confirmed. In general, the heterogeneity of diagnostic criteria as well as the variety of formulations to describe the symptomatology and different coding options make it difficult to clearly assign symptoms to a clinical picture. Exertion intolerance has been identified as a severe symptom of post-COVID-19 disorder. For this reason, recommendations in international guidelines are currently being revised, especially with regard to pacing. The implications for recommendations in tumor-related fatigue or due to multiple sclerosis are unclear.
CONCLUSION: Against the background of a decreasing burden of disease due to increasing vaccination rates, research on fatigue should not only include viral diseases.
