Long-term neuromuscular consequences of SARS-Cov-2 and their similarities with myalgic encephalomyelitis/chronic fatigue syndrome: results of the retrospective CoLGEM study

Abstract:

Background: Patients with long-COVID often complain of continuous fatigue, myalgia, sleep problems, cognitive dysfunction, and post-exertional malaise. No data are available on EMG recording of evoked myopotentials (M-waves) or exercise-induced alterations in long-COVID patients, providing evidence of muscle membrane fatigue. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develops in more than half of patients after an infectious disease, particularly viral diseases. A large proportion (around 70%) of these patients have neuromuscular disorders with M-wave alterations during and after exercise. Our hypothesis was that M-wave alterations would be also found in long-COVID patients, in association with neuromuscular symptoms, similar to ME/CFS.

Methods: This retrospective observational ColGEM (Covid LonG Encéphalomyelite Myalgique) study compared 59 patients with long-COVID and 55 ME/CFS patients with a history of severe infection who presented before the COVID pandemic. All of these patients underwent the same protocol consisting of a questionnaire focusing on neural and neuromuscular disorders and M-wave recording in the rectus femoris muscle before, during, and 10 min after a progressive cycling exercise. Maximal handgrip strength (MHGS) and maximal exercise power were also measured. The frequency of symptoms and magnitude of M-wave changes in the two groups were compared using non-parametric and parametric tests.

Results: The frequency of fatigue, myalgia, sleep problems, cognitive dysfunction, and post-exertional malaise as well as the magnitude of exercise-induced M-wave alterations were the same in the two groups. By contrast, digestive problems were less present in long-COVID. M-wave alterations were greater in ME/CFS patients as in those with long-COVID when the highest muscle strength and highest exercise performance were measured.

Conclusions: These high clinical and biological similarities between long-COVID and ME/CFS support the hypothesis that SARS-Cov-2 infection can cause ME/CFS symptoms. Trial registration Registered retrospectively.

Source: Retornaz F, Rebaudet S, Stavris C, Jammes Y. Long-term neuromuscular consequences of SARS-Cov-2 and their similarities with myalgic encephalomyelitis/chronic fatigue syndrome: results of the retrospective CoLGEM study. J Transl Med. 2022 Sep 24;20(1):429. doi: 10.1186/s12967-022-03638-7. PMID: 36153556. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-022-03638-7 (Full text)

The chronic fatigue syndrome

Abstract:

The chronic fatigue syndrome (CFS) including myalgic encephalomyelitis and the postviral syndrome is a term used today to describe a not fully recognized disease characterized primarily by chronic or recurrent debilitating fatigue and various combinations of neuromuscular and neuropsychological symptoms. The term CFS has been introduced and defined by the Centers for Disease Control (CDC) in Atlanta. Fatigue is one of the most common symptoms in medicine, but CFS as defined by CDC has appeared to be quite rare in the general population. Researchers have suggested that the syndrome is a heterogenous immunologic disorder that follows viral infection, but despite numerous studies on the subject the etiologic factor of the syndrome is unknown. CFS is a controversial diagnosis. In a very high percentage of patients with the CFS depression, phobias or anxiety disorders have frequently preceded the onset of the chronic fatigue. There are many overlapping symptoms between CFS and major depression. Some clinicians suggest that it is not obvious that CFS can be distinguished from neurasthenia.

 

Source: Białyszewski A. [The chronic fatigue syndrome]. Psychiatr Pol. 1993 Nov-Dec;27(6):601-11 [Article in Polish] http://www.ncbi.nlm.nih.gov/pubmed/8134494