Grau, J M, Casademont, J, Pedrol, E et al. · Clinical neuropathology · 1992
This study looked at muscle tissue samples from 20 ME/CFS patients to understand why muscles feel so tired and weak. The researchers found that most patients had either normal muscle tissue or only minor changes, and they did not find the patterns of inflammation typically seen in viral muscle diseases. The study also tested whether L-carnitine supplements could help patients improve over three months, but found no clinical benefit.
This early muscle pathology study directly addresses a core ME/CFS symptom—muscle fatigue and weakness—by examining tissue at the microscopic level. The findings help clarify whether muscle symptoms arise from viral infection or inflammation, which is crucial for guiding treatment approaches and understanding disease mechanisms.
This study does not prove that ME/CFS muscle problems are not biological in origin; absence of morphological changes or classic viral markers does not exclude abnormalities in muscle metabolism, energy production, or function at other levels. The negative L-carnitine result in this small sample does not definitively rule out potential benefit in other patient subgroups or with different dosing protocols. Lack of inflammatory markers does not exclude other immune mechanisms contributing to muscle dysfunction.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Grau, J M, Casademont, J, Pedrol, E, Fernández-Solà, J, Cardellach, F, Barros, N, et al. (1992). Chronic fatigue syndrome: studies on skeletal muscle.. Clinical neuropathology. https://pubmed.ncbi.nlm.nih.gov/1473316/
BibTeX
@article{mecfsatlas-grau-1992-chronic-fatigue,
author = {Grau, J M and Casademont, J and Pedrol, E and Fernández-Solà, J and Cardellach, F and Barros, N and Urbano-Márquez, A},
title = {Chronic fatigue syndrome: studies on skeletal muscle.},
journal = {Clinical neuropathology},
year = {1992},
note = {PubMed: 1473316},
url = {https://www.mecfsatlas.com/evidence/grau-1992-chronic-fatigue},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/grau-1992-chronic-fatigue
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