|Year : 2021 | Volume
| Issue : 2 | Page : 72-75
Auditory manifestations associated post-COVID-19: What we need to know?
Nithya Arigapudi1, Tarun Kumar Suvvari2, PS N Murthy3
1 Dr. Pinnamaneni Siddhartha Institute of Medical Sciences and Research Foundation (Dr. PSIMS and RF), Vijayawada, Andhra Pradesh, India
2 Dr. NTR University of Health Sciences, Vijayawada, Andhra Pradesh, India
3 Principal and Professor of ENT-HNS, Dr. Pinnamaneni Siddhartha Institute of Medical Sciences and Research Foundation (Dr. PSIMS and RF), Vijayawada, Andhra Pradesh, India
|Date of Submission||27-Jun-2021|
|Date of Decision||28-Jun-2021|
|Date of Acceptance||28-Jun-2021|
|Date of Web Publication||20-Dec-2021|
Mr. Tarun Kumar Suvvari
Dr. NTR University of Health Sciences, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Post-acute Coronavirus Disease 2019 (COVID-19) syndrome is currently an emerging condition, however, there is only a little research information on these post-COVID-19 symptoms, especially auditory manifestations, which have been in the limelight recently among the COVID-19 recovered patients. Tinnitus and conductive/sensorineural hearing loss were the most commonly reported manifestations post-COVID-19, while vertigo, otitis externa, and ear pain were the least reported. Here, we have discussed relevant auditory manifestations in theoretical and practical terms; considering the mechanisms of causation, published literature on auditory involvement in patients post-COVID-19, and during the active stage of the disease, and whether this could result in long-term complications.
Keywords: Auditory problems, hearing loss, post-COVID-19, tinnitus
|How to cite this article:|
Arigapudi N, Suvvari TK, N Murthy P S. Auditory manifestations associated post-COVID-19: What we need to know?. J NTR Univ Health Sci 2021;10:72-5
|How to cite this URL:|
Arigapudi N, Suvvari TK, N Murthy P S. Auditory manifestations associated post-COVID-19: What we need to know?. J NTR Univ Health Sci [serial online] 2021 [cited 2023 Mar 21];10:72-5. Available from: https://www.jdrntruhs.org/text.asp?2021/10/2/72/332855
| Introduction|| |
Defining the post-infection manifestations of any disease is as important as defining its clinical features of presentation; the patient and physician both must know whether a symptom is a complication, a new disease, or merely a side effect of harboring the initial disease process. Considering the similarity between the severe acute respiratory syndrome (SARS)-CoV-2 virus and the previous coronaviruses—SARS-CoV and the Middle East respiratory syndrome (MERS-CoV), it is expected that following the present acute phase of COVID-19, a group of patients will likely suffer from a post-acute COVID-19 syndrome as was seen in SARS and MERS. Although there have been tremendous strides in research on COVID-19 in regards to the symptoms, treatment modalities, and complications; there have been a few researches regarding the post-COVID-19 manifestations; and among the few studies conducted, the auditory impact of the SARS-CoV-2 virus is rarely talked about although there are strong theoretical implications on the possible involvement.
| Post-COVID-19 Auditory Manifestations|| |
Based on published literature to date, there are six major studies that highlighted the role of auditory problems, of which five were original research studies and one was a case report. In the study by Iqbal A, et al. 158 patients of COVID-19 from Karachi were evaluated for post-recovery symptoms and it was found that 94.9% had experienced at least one long COVID-19 symptom, and 19% of the patients reported 'tinnitus' after COVID-19 recovery. Kamal M, et al. reported that out of the 287 COVID-19 survivors they studied, 90.2% experienced post-COVID-19 manifestations, and 16.7% of the patients had reported 'tinnitus' following COVID-19 recovery; while in an online survey study by Lambert NJ, et al. out of more than 1,567 responses, 267 responded for clogged ears and 233 responded for tinnitus. These studies, though conducted with an aim of listing the different symptoms that one could present with post-COVID 19, highlighted the fact that there was a significant amount of auditory involvement, which one can say was not expected, considering the lack of literature stating such involvement in patients of SARS and MERS.
In the study by Munro KJ, et al. 138 patients were followed up for auditory symptoms after 8 weeks of COVID-19 discharge, and 16 (13.2%) patients were found to have a change in hearing and/or tinnitus; however, the symptoms were self-reported, and were not backed by auditory assessment. In another study by Gallus R, et al. a group of 48 patients was examined and compared with a control group (n = 28) within 2 weeks after their second negative swab. Of the initial cohort, 41 were ultimately eligible for auditory comparison (7 were excluded on the basis of pre-existing hearing loss); among them, 4 reported subjective hearing loss, and 2 reported tinnitus. On examination, all of them appeared to have a normal hearing threshold (based on American Speech-Language-Hearing Association (ASHA) classification), and when the cases and controls were compared by pure tone audiometry no difference was noted. However, on comparison of single frequencies, the former COVID-19 patients had significantly higher thresholds for 0.25 kHz while the controls had significantly higher thresholds for 2 and 4 kHz. The average difference between the two groups for the mentioned frequencies was considered not clinically relevant, being only 1.4, 1.6, and 3.2 dB, respectively. In a case report by Koumpa FS, et al. a 45-year-old patient presented with sudden-onset sensorineural hearing loss (SSNHL) post-COVID-19 recovery. He reported tinnitus in the left ear along with a sudden hearing loss. The patient did not have any previous history of ear problems or hearing loss, and all investigations for other causes of unilateral SSNHL came negative.
Overall, tinnitus and conductive/sensorineural hearing loss were the most commonly reported manifestations post-COVID-19, while vertigo, otitis externa, and ear pain were the least reported. No records of auditory symptoms were noted with the earlier types of coronaviruses (SARS and MERS), however, in the case of the novel coronavirus, there are case studies and surveys reporting auditory symptoms as both presenting and post-COVID-19 symptoms, yet the literature cannot be said to be adequate. There is also a lack of dedicated screening in hospitals, which pushes the patient into an area of risk, as the window for treatment of these conditions is often a narrow one.
| Mechanism of Audiovestibular Involvement|| |
Many hypotheses have been put forth to suggest the mechanism of the involvement of the audiovestibular system but the actual mechanism is yet to be known. One explanation suggests that viral damage, which is typically intracochlear, may affect the auditory brainstem: As direct damage to the organ of Corti, stria vascularis, or spiral ganglion, or as secondary damage induced by host-mediated immunity against virally expressed proteins. Although the virus' neurotrophic and neuroinvasive capabilities are still being investigated, there is supporting evidence suggesting that as some patients present with direct signs of hypercoagulability, there may be vasculitis or vasculopathy involved in the pathogenesis, which can ultimately cause hearing and balance alterations.
Another hypothesis gaining popularity is the involvement of the 'glymphatic' system, which would be best described as a brain-wide network of perivascular channels through which subarachnoid Cerebrospinal fluid (CSF) recirculates to facilitate the clearance of interstitial solutes; this system includes a pathway in the immediate vicinity of the olfactory nerve fibers that allows drainage of CSF through the cribriform plate into the lymphatic vessels. As SARS-CoV-2 causes damage to the olfactory epithelium, characterized by anosmia or hyposmia, it may lead to increased resistance of CSF outflow through the cribriform plate; moreover, the virus can also affect the lymph endothelial cells, and hence, cause blockage of lymphatics as well. Both these mechanisms may result in the production of a post-COVID-19 IIH-like (idiopathic intracranial hypertension) syndrome with audiovestibular implications.
A point to be noted is that the studies and surveys that have been made so far regarding COVID-19 and its auditory manifestations have not taken into consideration the relationship of these clinical features with the therapeutic drugs, like that of antiviral medications and chloroquine and/or hydroxychloroquine which were widely utilized, and are known to be associated with adverse effects (ototoxicity) like mild hearing loss, tinnitus, and vertigo.,
| Discussion|| |
It is clear that there is less attention on the relationship between COVID-19 and auditory symptoms in the medical literature; but whether this lack stems from the fact that the symptoms are uncommon, or that simply, more attention is being paid to life-threatening symptoms at present, is unclear. Despite the evidence that there is most probably a 'post-COVID-19 syndrome,' it is yet to be defined in terms of symptoms, and whether the auditory involvement is a major or minor factor; a question which has been given different answers in lieu of the results by different studies. For example, in the study by Gallus R, et al. on 48 patients, despite the limitations of the study, there were no definite signs of auditory damage post-COVID, even if involvement was present during the disease, whereas in the study by Munro KJ, et al. more than 1 in 10 patients had reported a change in their hearing status post-COVID, which would be considered significant. One thing common to all the studies was that the bottom line stated that there still was adequate research required before a conclusion could be formed. At present, we remain unclear on the mechanism of auditory involvement, the extent of involvement, the long-term effects of the involvement, and we also do not know how external factors can come into play. For instance, anxiety and stress, which have a bidirectional relationship with tinnitus and which are common among the public in these testing times, or age and education status, as the elderly, and people with lower levels of education will tend to under-report their symptoms, the effect of various drugs, and the fact that all patients are not affected the same way in terms of severity—all have possible roles to play.
| Conclusion|| |
Ultimately, there is an urgent need for international research on auditory complications post-COVID-19 to provide us better insights into the situation. The establishment of screening facilities and protocols for COVID-19 patients would have definite benefits in reducing the morbidity of the affected patients, but the extent of such benefits and provision of standard protocols to be followed can only be told by multicentric national and global studies.
We would like to thank Dr. Pinnamaneni Siddhartha Institute of Medical Sciences and Research Foundation (Dr. PSIMS and RF) and Squad Medicine and Research (SMR) for their support and guidance.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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