Letter to the Editor in Reference to “New Onset Vertigo After COVID-19 Infection” – COVID-19-related Vestibular Neuritis: Case Series and Review of the Literature

interest the article by Motawea et al. report-ing the case of a sudden vertigo in a 60-year-old woman with a confirmed Coronavirus-Disease-19 (COVID-19) [1]. The authors concluded that Severe-Acute-Respiratory-Syndrome-Coronavirus-2 (SARS-COV-2) may lead to vestibular neuritis (VN), but more well-designed observational studies with a larger sample size are needed to establish a definite association between COVID-19 and vertigo. The incidence of vestibular disorders in COVID-19 patients is still unknown and varies across different stud - ies. We reviewed the international literature of COVID-19-related vestibular disorders and the electronic database at our department, a tertiary referral centre for audiovestibular disorders. In January 2022 a structured search of the English literature published on PubMed was performed by searching the terms “vestibular neuritis” and “COVID-19”. Only inherent reports with SARS-CoV-2-positive patients, as confirmed by molecular nasopharyngeal swab, and with detailed clinical and diagnostic data were considered.

In 5 French hospitals, over the period February-May 2020, comparing with 2018 and 2019, no significant increase in admission for acute peripheral vestibulopathy (APV) was observed. Moreover, significant differences among hospitals located in COVID-19 high-and low-risk zones, or significant increase in the severity of the APV cases was observed. Accordingly, a retrospective review of acute cochleovestibular disorders after and before pandemic conducted at our department found no significant changes regarding incidence of APV. [2].
Only 6 cases of instrumentally confirmed VN simultaneous to COVID-19 have been reported to date, and two more cases occurred at our department. Differential diagnosis has to be considered regarding a first episode of Ménière's disease or vestibular migraine attack, thus an accurate diagnostic workout should be mandatory. [3] The mechanism by which SARS-CoV-2 can cause VN is unclear and speculative. Motawea et al. supported viral and post-viral inflammatory disorders. [1] Indeed, the cell receptor angiotensin-converting enzyme 2 (ACE2), which allows intracellular entry of SARS-CoV-2, has been found in nasal tissues in murine and human model and in Eustachian tube, middle ear and cochlear tissues in murine model. On the other hand, physical and emotional stress experienced by infected people could play a role in the expression of vestibular symptoms -as occurred for headache patients -or could have triggered the reactivation of possible latent viruses (e.g., HSV-1). The latter mechanism could be hypothesised especially in patients in which VN was not present at COVID-19 symptoms onset but later during the course of the disease. [4,5].

Dear Editor,
We read with interest the article by Motawea et al. reporting the case of a sudden vertigo in a 60-year-old woman with a confirmed Coronavirus-Disease-19 (COVID-19) [1]. The authors concluded that Severe-Acute-Respiratory-Syndrome-Coronavirus-2 (SARS-COV-2) may lead to vestibular neuritis (VN), but more well-designed observational studies with a larger sample size are needed to establish a definite association between COVID-19 and vertigo.
The incidence of vestibular disorders in COVID-19 patients is still unknown and varies across different studies. We reviewed the international literature of COVID-19-related vestibular disorders and the electronic database at our department, a tertiary referral centre for audiovestibular disorders. In January 2022 a structured search of the English literature published on PubMed was performed by searching the terms "vestibular neuritis" and "COVID-19". Only inherent reports with SARS-CoV-2-positive patients, as confirmed by molecular nasopharyngeal swab, and with detailed clinical and diagnostic data were considered.  To the best of our knowledge, even if COVID-19 infection seems not to increase the risk of VN occurrence, it would be appropriate to routinely test for SARS-CoV-2 infection patients with diagnosed VN. Moreover, prospective studies on a large series of COVID-19 patients should try to better define the epidemiology of cochlear-vestibular involvement and elucidate the SARS-CoV-2-related prognosis on peripheral and central audiovestibular functions. Among patients that can't be easily visited due to quarantine regimen, a telemedicine evaluation could be helpful.

Author Contributions
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Andrea Frosolini and Daniela Parrino. The first draft of the manuscript was written by Andrea Frosolini and Daniela Parrino and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
Funding Open access funding provided by Università degli Studi di Padova within the CRUI-CARE Agreement.

Declarations
The authors have no conflicts of interest to disclose. Informed consent was obtained from all individual participants included in the study. The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Conflict of Interest
No funds, grants, or other support was received. The authors have no relevant financial or non-financial interests to disclose.
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