Azcue, N, Del Pino, R, Acera, M et al. · Journal of translational medicine · 2023 · DOI
This study compared how the nervous system works differently in people with ME/CFS, people with long COVID, and healthy people. Researchers tested heart rate responses, sweating patterns, and how nerves respond to temperature. They found that people with ME/CFS had more severe problems with heart rate regulation and nerve fiber damage than those with long COVID, and both groups had more problems than healthy controls.
This study provides objective biomarkers—autonomic dysfunction and small fiber neuropathy—that may help explain why ME/CFS patients experience fatigue, brain fog, and orthostatic symptoms. By comparing ME/CFS directly to post-COVID and healthy controls, it clarifies which features are specific to ME/CFS versus shared post-viral presentations, potentially supporting better diagnostic and treatment approaches.
This cross-sectional design cannot establish causation or determine whether autonomic and neuropathic abnormalities cause symptoms or result from them. The study does not prove these markers are disease-defining or would be present in all ME/CFS patients, as findings reflect group averages with individual variation. Long-term progression and treatment response are not addressed.
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
Azcue, N, Del Pino, R, Acera, M, Fernández-Valle, T, Ayo-Mentxakatorre, N, Pérez-Concha, T, et al. (2023). Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome.. Journal of translational medicine. https://doi.org/10.1186/s12967-023-04678-3
BibTeX
@article{mecfsatlas-azcue-2023-dysautonomia-small,
author = {Azcue, N and Del Pino, R and Acera, M and Fernández-Valle, T and Ayo-Mentxakatorre, N and Pérez-Concha, T and Murueta-Goyena, A and Lafuente, J V and Prada, A and López de Munain, A and Ruiz Irastorza, G and Martín-Iglesias, D and Ribacoba, L and Gabilondo, I and Gómez-Esteban, J C and Tijero-Merino, B},
title = {Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome.},
journal = {Journal of translational medicine},
year = {2023},
doi = {10.1186/s12967-023-04678-3},
note = {PubMed: 37968647},
url = {https://www.mecfsatlas.com/evidence/azcue-2023-dysautonomia-small},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/azcue-2023-dysautonomia-small
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