Since Wuhan's "closure" in December 2019, novel coronavirus pneumonia (new coronavirus pneumonia, COVID-19) has been familiar to the people of the whole country. The unprecedented "escape" and the tragic "retrograde" have remained in the hearts of the people of Wuhan and the people of the whole country. In the next three years, the new coronavirus spread all over the world, swallowing countless lives and leaving endless trauma. In addition to common respiratory damage, COVID-19 can leave "traces" in the cardiovascular system, digestive system, urogenital system, mental and psychological aspects. Will COVID-19 have an impact on nervous system , especially the auditory and vestibular? We review it through the literature.
Author: Tinyel
This article is published by the author's authorized Yimaitong, please do not reprint without authorization.
The effect of COVID-19 on hearing and vestibular
From the literature, COVID-19 has an impact on hearing and vestibular . It can be analyzed from three aspects: symptoms, causes/mechanisms, and diseases.
➤Audible-Vestibular Symptoms
Tinnitus , Hearing Loss, Dizziness/Dirty, Balance Disorder.
In the study by Viola et al., 23.2% of patients with COVID-19 experienced tinnitus, 18.4% of patients with balance disorders, 94.1% of the latter experienced dizziness, and 5.9% had acute vertigo attacks. They believe that viral infection can damage inner ear cells, cause hearing loss, and some may even affect the auditory brainstem; the virus is neuroinvasive, and it has been confirmed that there are neuroorologic symptoms related to coronavirus, such as tinnitus and balance disorders, so there is a correlation between COVID-19 and auditory-vestibulum symptoms. The impact of the new coronavirus on neuronal tissue may be due to the direct infection of the virus in central nervous system , or it may be related to vascular damage caused by vasculitis and vascular disease, and is similar to the mechanisms of varicella zoster virus (VZV) and human immunodeficiency virus (HIV). Primary and secondary vasculitis is usually associated with auditory-vestibulo symptoms, and dizziness can occur in primary cardiovascular disease.
In another study of COVID-19 and auditory-vestibules, tinnitus was the most common auditory-vestibules symptom with a prevalence of about 14.8%. Most studies have reported that patients experience tinnitus in the early stages of COVID-19, but some have also recorded that patients only experience tinnitus in the late stages of COVID-19, and last for several days to weeks, but will not last. The types of tinnitus are diverse, some are intermittent, some are continuous, and some are pulsating.
In Fancello et al.'s study, hearing loss is the most common auditory-vestibulo symptom, which can occur in isolation or with tinnitus or vertigo. The hearing loss associated with COVID-19 is very similar to typical sudden sensorineural deafness, but there are also reports of conductional deafness, and hearing loss can occur unilaterally or bilaterally, mildly or moderately.
➤ Possible Causes/Mechanisms
Currently, it is believed that the impact of new coronavirus on the auditory-vestibules is mainly caused by the following reasons:
1. Cochlearitis, neuritis
2. Cross-reaction
3. Vascular disease
4. Immune mediation
5. The drugs used to treat new coronavirus pneumonia have ototoxicity
virus involves the inner ear or vestibular cochlear nerves causing cochlearitis or neuritis, which may lead to dizziness, tinnitus and hearing damage. Therefore, it can be considered that coronavirus has similar nerve tendencies.
ischemia is prone to occur due to insufficient collateral blood supply of cochlear and semicircular canal. Microvascular damage can affect the central and peripheral nervous systems, causing various neurological symptoms such as headache and dizziness.
immune-mediated responses such as proinflammatory cytokine production and vascular events that may negatively affect the auditory vestibular system. Cross-reaction of
antibody or T cells may mistake the inner ear antigen as a virus, resulting in accidental damage to the inner ear.
Patients with COVID-19 are easily receptive to drugs with potential ototoxicity during the treatment process, such as hydroxychloroquine and azithromycin.Nearly 12% of European patients with COVID-19 have taken hydroxychloroquine and chloroquine , including azithromycin in multiple treatment options for COVID-19. These antiviral drugs have adverse effects in clinical practice, including tinnitus and hearing loss. These symptoms may be misdiagnosed as caused by COVID-19.
➤ Common diseases
The vestibular diseases currently reported in new coronary pneumonia are mainly vestibular neuritis (VN) and benign paroxysmal positional vertigo (BPPV).
Mat et al. reported a case of COVID-19 with VN as the clinical manifestation. The patient was a 13-year-old female patient with sudden persistent rotational dizziness and severe vomiting without fever. The patient had no hearing loss, tinnitus, ear pain, or headache, and had no previous history of vertigo. physical examination found spontaneous horizontal rotational nystagmus on the right, and the in-situ stance test turned left, vHIT showed a decrease in VOR gain and saccade tracking on the left anterior and external semicircular canals. Therefore, the diagnosis of VN is clarified. During her hospitalization, she was diagnosed with COVID-19 because her family was diagnosed with COVID-19 and her nasal swab test was positive. Jeong reported a 54-year-old man diagnosed with VN after receiving the COVID-19 vaccine. The patient developed dizziness two days after receiving the first dose of Pfizer-BioNTech COVID-19 vaccine. The patient has no previous history of hearing loss and has recently had a supreme respiratory infection . Physical examination revealed spontaneous horizontal torsional nystagmus on the right side, and no signs of central vertigo were found. After 3 days of conservative treatment, the VOR gain of the left lateral semicircular canal without saccade tracking was finally found in vHIT, so it was diagnosed as upper left VN. Inflammation caused by the virus may be the mechanism of VN development in patients with COVID-19.
In a study of patients with acute vertigo after receiving the COVID-19 vaccine, , found that all patients with level or rotational nystagmus were diagnosed with BPPV, accounting for 27% of all patients with acute vertigo. Some researchers believe that long-term hospitalization and bed rest may lead to otolith loss and cause BPPV.
Other reported diseases include unilateral peripheral vestibular disease after receiving the COVID-19 vaccine, and COVID-19 pneumonia manifested in acute labyrinthitis.
Other views
There was a study that conducted a retrospective analysis of 48 recovered COVID-19 patients. After comparing the age-gender matching pure tone listening thresholds, it was found that among individual frequencies, COVID-19 patients were different from the control group, but the difference was very small, and all patients were within the normal range of these frequencies; and in their study, no COVID-19 patients experienced objective hearing loss due to COVID-19. Therefore, they believe that even if the COVID-19 causes damage to the cochlear, it is temporary.
Because of the need to be equipped with protective equipment and carefully disinfected all surfaces, it is difficult for patients with COVID-19 to undergo a complete vestibular assessment, and the chance of vomiting during the examination increases the risk of infection. Therefore, few studies have conducted vestibular function examinations in patients with COVID-19 who have vestibular symptoms. Some researchers found that the gain value of the right anterior tube vHIT in patients with COVID-19 was significantly different from that in the control group, and there was no dominant or implicit saccade. Therefore, they believe that no clinically relevant signs of vestibular injury were found in previous patients with COVID-19. Whether patients with COVID-19 have transient vestibular nerve damage and subsequently recover completely, and what causes this injury is not known, but minor vestibular symptoms such as dizziness and balance disorder may be the result of severe weakness and fatigue in patients with COVID-19, or the normal nerve reaction of COVID-19. Similarly, many scholars believe that the auditory-vestibule symptoms of patients with COVID-19 may be caused only by anxiety and stress caused by severe impact on life and work in the context of the pandemic, or by anxiety, or by anxiety.
The comprehensive tertiary hospital where the author is located is a local designated hospital for COVID-19. Since the outbreak of the COVID-19 outbreak, it is the only hospital in the province that has never stopped receiving COVID-19 patients. Judging from our data, there are very few patients with auditory-vestibule symptoms. Perhaps this also reflects that the impact of COVID-19 on auditory-vestibule is not common or that we focus more on more serious symptoms, while ignoring auditory and vestibular symptoms.
References:
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