Key Pathophysiological Role of Skeletal Muscle Disturbance in Post COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Accumulated Evidence.
Level 5 - mechanism / opinion, no new human data
Narrative review and mechanistic synthesis without systematic methodology or new primary data
PubMed 39727052 · doi:10.1002/jcsm.13669
What was done
The authors reviewed and synthesized published experimental literature regarding skeletal muscle pathophysiology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-COVID syndrome (PCS). They evaluated mechanistic evidence regarding hypoperfusion, intracellular ion disturbances (sodium and calcium overload), post-exercise tissue damage, and mitochondrial dysfunction.
What was found
The abstract provides a narrative synthesis without pooled quantitative data or statistical effect sizes. Reported qualitative findings from cited literature include: - Electron microscopy shows mitochondrial damage in ME/CFS skeletal muscle with preferential subsarcolemmal localization (not observed in non-ME/CFS post-COVID syndrome). - Muscle biopsies taken one day post-exercise in post-COVID ME/CFS display simultaneous signs of necrosis and regeneration. - Muscle MRI demonstrates elevated intracellular sodium in ME/CFS that correlates inversely with handgrip strength. - Histological evaluations exclude microvascular obstruction, viral presence, or autoimmune myositis as the primary drivers of exercise-induced muscle damage.
Why it matters
The review synthesizes recent tissue biopsy and magnetic resonance spectroscopy findings to propose a mechanistic model linking exercise-induced sodium/calcium overload and mitochondrial injury to post-exertional malaise in ME/CFS and post-COVID syndrome.
Limits
This is a narrative review rather than a systematic review or meta-analysis. No search methodology, inclusion criteria, study quality appraisal, sample sizes, or quantitative effect estimates are reported in the abstract.