Vagus Nerve Neuropathy in SARS-CoV-2 Infection: An Ultrasound Study

Authors

  • Jelena Mićić Sixth-year Medical Student. Faculty of Medicine, Military Medical Academy, University of Defence, Belgrade, Serbia

DOI:

https://doi.org/10.5195/ijms.2025.4085

Keywords:

vagus nerve, ultrasonography, SARS-CoV-2, cytokine storm

Abstract

Background: The vagus nerve regulates systemic inflammation through the inflammatory reflex arc. Afferent fibers detect cytokines and relay signals to the brainstem, which activates parasympathetic pathways to suppress inflammation via acetylcholine release in the spleen. Disruption of this “brake system” can lead to cytokine storm, a driver of severe COVID-19. Beyond COVID-19, vagal dysfunction is also implicated in atherosclerosis, asthma, diabetes, Crohn’s disease, ulcerative colitis, and autoimmune thyroiditis.

 

Aim: To determine whether vagus nerve neuropathy can be detected in SARS-CoV-2–infected patients using ultrasound, and to assess its contribution to COVID-19 pathophysiology and related inflammatory conditions.

 

Methods: A prospective study was conducted between October 2021 and April 2022, including 68 patients (mean age 53.1 ± 14.3 years) with PCR-confirmed Delta variant infection and 50 healthy controls (mean age 22.7 ± 2.4 years). Exclusion criteria for controls included chronic illness or medication affecting autonomic function. Ultrasound was performed with a 10–18 MHz linear probe, with patients supine or in lateral decubitus position. The vagus nerve was examined bilaterally at two levels: X1 (carotid bifurcation) and X2 (cricoid cartilage). Cross-sectional area (CSA) was traced just outside the hyperechoic rim. Each measurement was repeated by two independent operators. Data were analyzed using Mann–Whitney U tests (IBM SPSS v26).

 

Results: On the left side, X1 values did not differ, while X2 showed a borderline increase in the COVID group (p=0.05). On the right side, both X1 and X2 were nearly doubled in COVID-19 patients compared to controls (p<0.001). Median CSA values were consistently higher in patients (Left X1: 0.77 vs 0.70 mm²; Left X2: 0.87 vs 0.70 mm²; Right X1: 1.20 vs 0.60 mm²; Right X2: 1.30 vs 0.70 mm²). Importantly, this enlargement was observed despite the older age of the patient group, where smaller nerve dimensions would normally be expected. This contrast reinforces the likelihood of pathological involvement rather than age-related variation.

 

Conclusion: Ultrasound revealed enlargement of the vagus nerve in COVID-19 patients, most prominently on the right side. Although ultrasound cannot fully distinguish edema from structural neuropathy, the consistent enlargement justifies use of the term neuropathy in a broad sense. These findings support the hypothesis that vagus nerve dysfunction contributes to cytokine storm and severe outcomes in SARS-CoV-2 infection. Moreover, ultrasound emerges as a simple, bedside, non-invasive tool to study cranial nerves in vivo. Given the role of the inflammatory reflex in many chronic diseases, these results may extend beyond COVID-19, offering opportunities for diagnostics, monitoring, and therapeutic interventions targeting vagal pathways.

References

None

Downloads

Published

2025-12-31

How to Cite

Mićić, J. (2025). Vagus Nerve Neuropathy in SARS-CoV-2 Infection: An Ultrasound Study. International Journal of Medical Students, 13, S187. https://doi.org/10.5195/ijms.2025.4085

Issue

Vol 13. (2025): Supplement 1

Section

Abstracts of the WCMSR

Categories

License

Copyright (c) 2025 Jelena Mićić

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

  1. The Author retains copyright in the Work, where the term “Work” shall include all digital objects that may result in subsequent electronic publication or distribution.
  2. Upon acceptance of the Work, the author shall grant to the Publisher the right of first publication of the Work.
  3. The Author shall grant to the Publisher and its agents the nonexclusive perpetual right and license to publish, archive, and make accessible the Work in whole or in part in all forms of media now or hereafter known under a Creative Commons Attribution 4.0 International License or its equivalent, which, for the avoidance of doubt, allows others to copy, distribute, and transmit the Work under the following conditions:
    1. Attribution—other users must attribute the Work in the manner specified by the author as indicated on the journal Web site; with the understanding that the above condition can be waived with permission from the Author and that where the Work or any of its elements is in the public domain under applicable law, that status is in no way affected by the license.
    2. The Author is able to enter into separate, additional contractual arrangements for the nonexclusive distribution of the journal's published version of the Work (e.g., post it to an institutional repository or publish it in a book), as long as there is provided in the document an acknowledgment of its initial publication in this journal.
    3. Authors are permitted and encouraged to post online a prepublication manuscript (but not the Publisher’s final formatted PDF version of the Work) in institutional repositories or on their Websites prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work. Any such posting made before acceptance and publication of the Work shall be updated upon publication to include a reference to the Publisher-assigned DOI (Digital Object Identifier) and a link to the online abstract for the final published Work in the Journal.
    4. Upon Publisher’s request, the Author agrees to furnish promptly to Publisher, at the Author’s own expense, written evidence of the permissions, licenses, and consents for use of third-party material included within the Work, except as determined by Publisher to be covered by the principles of Fair Use.
    5. The Author represents and warrants that:
      1. the Work is the Author’s original work;
      2. the Author has not transferred, and will not transfer, exclusive rights in the Work to any third party;
      3. the Work is not pending review or under consideration by another publisher;
      4. the Work has not previously been published;
      5. the Work contains no misrepresentation or infringement of the Work or property of other authors or third parties; and
      6. the Work contains no libel, invasion of privacy, or other unlawful matter.
    6. The Author agrees to indemnify and hold Publisher harmless from the Author’s breach of the representations and warranties contained in Paragraph 6 above, as well as any claim or proceeding relating to Publisher’s use and publication of any content contained in the Work, including third-party content.

Enforcement of copyright

The IJMS takes the protection of copyright very seriously.

If the IJMS discovers that you have used its copyright materials in contravention of the license above, the IJMS may bring legal proceedings against you seeking reparation and an injunction to stop you using those materials. You could also be ordered to pay legal costs.

If you become aware of any use of the IJMS' copyright materials that contravenes or may contravene the license above, please report this by email to contact@ijms.org

 

Infringing material

If you become aware of any material on the website that you believe infringes your or any other person's copyright, please report this by email to contact@ijms.org