Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

Original Article

SMJ

Santosh Kumar Swain, MS, DNB, MNAMS*, Somadatta Das, MA**, Smarita Lenka, M.Sc.*

*Department of Otorhinolaryngology, IMS and SUM hospital, Siksha “O” Anusandhan University, K8, Kalinganagar, Bhubaneswar-751003, Odisha, India.

**Central Research Laboratory, IMS and SUM hospital, Siksha “O” Anusandhan University, K8, Kalinganagar, Bhubaneswar-751003, Odisha, India.

Sudden Sensorineural Hearing Loss among

COVID-19 Patients-Our Experiences at an Indian

Teaching Hospital

ABSTRACT

Objective: To study the sudden sensorineural hearing loss (SSNHL) in patients with COVID-19 infections.

Methods: is is a retrospective descriptive study. ere were 16 COVID-19 patients participated in this study

those presented with sudden sensorineural hearing loss (SSNHL). e study was done between March 2020 to

August 2020. All these patients were diagnosed with SARS-CoV-2 infection with help of the reverse transcription

polymerase chain reaction (RT-PCR) testing.

Results: Out of 652 COVID-19 patients, 16 (2.45%) patients diagnosed with SSNHL. Out of 16 patients with

SSNHL, 11 (68.75%) were male and 5 (31.25%) were female with male to female ratio of 2.2:1. e age ranges of

the participants were 38 to 72 years with a mean age of 48.42 years. ere were 14 (87.50%) patients were presented

with unilateral and 2 (12.50%) were presented with bilateral SSNHL. ere were le sided SSNHL in 9 patients

(56.25%) and right side SSNHL in 5 patients (31.25%).

Conclusion: ere should be continuous monitoring of the SSNHL. Tracing COVID-19 infection is needed to

ensure a detailed understanding of this inner ear pathogenesis.

Keywords: COVID-19 patients; SARS-CoV-2; sudden sensorineural hearing loss (Siriraj Med J 2021; 73: 77-83)

Corresponding author: Santosh Kumar Swain

E-mail: santoshvoltaire@yahoo.co.in

Received 9 September 2020 Revised 2 November 2020 Accepted 3 November 2020

ORCID ID: http://orcid.org/0000-0001-7933-4414

http://dx.doi.org/10.33192/Smj.2021.11

INTRODUCTION

Hearing loss has a vital role in speech and communication

and can cause an invisible handicap of the aected person

and psychological solitary connement. e World health

organization (WHO) has documented that around 360

million people with disabling hearing loss in the world

which proved that more than half of the persons with a

hearing handicap can be prevented by early diagnosis

and treatment.

e association between the COVID-19

infection and sudden sensorineural hearing loss makes

intuitive sense, given the neuropathic manifestations of

the inner ear and auditory nerve. Although certain viral

infections cause hearing loss, there is still unknown whether

COVID-19 infection leads to auditory dysfunction or not.

COVID-19 infection is highly contagious and seen in the

respiratory system due to the novel virus SARS-CoV-2

(Fig 1).

ere are several causes for hearing loss in clinical

practice. Viral etiology is oen ignored during assessing

hearing loss. Viral infections like cytomegalovirus (CMV)

cause congenitally acquired hearing loss and many other

Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

viruses are also associated with congenital or acquired

hearing loss.

Typically viruses cause sensorineural

hearing loss. e viral etiology is oen proposed for

the etiology of otosclerosis.

HIV infection can cause

conductive hearing loss through fungal and bacterial

infections which are frequent aer immunosuppression

by the virus. e hearing loss by viral etiology can be

mild or severe to profound, unilateral or bilateral. In

COVID-19 infections, the development of the SSNHL is

rare and the exact etiopathology is dicult to explain in

this current pandemic. Here this study is relating to the

impact or incidence of the novel corona virus infection

on the auditory system with the manifestation of SSNHL.

MATERIALS AND METHODS

is retrospective study was conducted at a tertiary

care teaching hospital. e study was done during the

period between March 2020 to August 2020. is study

was approved by the Institutional ethical committee (IEC)

with reference number IEC/IMS/SOA/21/12.3.2020. e

COVID-19 patients with sudden sensorineural hearing

loss (SSNHL) were participated in this study. e patient

details were collected from the patient les of the hospital.

Informed consent was obtained from the patients those

participated in this study. e audiological symptoms

were searched from 652 COVID-19 patients at COVID-19

hospital. e eligible candidates were presented with

SSNHL. SSNHL was dened as a hearing loss of more than

30 decibel at three consecutive frequencies at least over

a period of less than 3 days.

Audiological assessments

were done by tuning fork test, pure tone audiometry

and tympanometry. All the COVID-19 patients those

complained of sudden hearing loss were evaluated by

otolaryngologists. ose patients discharged from the

COVID hospital with a history of SSNHL and conrmed

with investigations were also included in this study. All

the patients those participated in this study were tested

positive reverse transcription polymerase chain reaction

(RT-PCR) for SARS-CoV-2 before admission to the COVID

hospital. COVID-19 patients with a previous history of

hearing loss and any association such as a history of the

ototoxic drugs, noise exposure, age related hearing loss,

measles, mumps, rubella, meningitis, syphilis, hypertension,

thyroid diseases, diabetes mellitus and kidney diseases

were excluded from this study. COVID-19 patients with

a history of oral hydroxychloroquine taken previously

were excluded from this study. Proper history taking and

otological examinations including tuning fork tests were

done in all the participants before audiological testing.

All the participating patients were underwent pure tone

audiometry testing, tympanometry and Otoacoustic

emissions (OAE) which were done by an audiologist

in a soundproof room. e pure tone audiometry was

performed with all safety protocols for the COVID-19

pandemic. Pure tone audiometry ndings were done

with frequency at 250, 500, 100, 2000, 4000 and 8000Hz

using Telephonics TDH39 earphones. e audiometric

assessment was conducted in a sound treated room,

using GSI 61 clinical audiometer. e average value for

the hearing threshold at 500Hz, 1000Hz and 2000Hz

was calculated. e pure tone average greater than 25

decibels was considered as hearing loss. Tympanometry

was carried out with help of the amplaid 775 middle

ear analyzer to rule out middle ear pathology. Before

performing the pure tone audiometry, tuning fork tests

were done by using 256,512 and 1024 Hz tuning forks.

Transient evoked otoacoustic emissions (TEOAEs) were

recorded in all participating patients with help of the

Madsen Capella Analyzer. e stimuli in TEOAEs were

a nonlinear click of about 80 dB peak SPL in the ear

canal. e spectrum analyzer was stimulated as 4ms

aer the presentation of the stimuli for avoiding the

ringing of the input stimuli and the temporal window

was set at 20ms. Magnetic resonance imaging (MRI) of

the brain was done in all the cases with SSNHL to nd

out the status of the inner ear. In this study, all the data

were recorded and analyzed by using Statistical Package

for Social Science (SPSS) soware, v20.

RESULTS

In this study, 652 COVID-19 patients were evaluated

to nd out hearing loss. Out of 652 patients, 16 (2.45%)

patients were diagnosed with SSNHL. ese 16 patients

underwent an audiological assessment at the otolaryngology

Fig 1. Structure of the COVID-19 virus (Red arrow is spike protein

over lipid membrane, yellow arrow indicates RNA).

Swain et al.

Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

Original Article

SMJ

department. All the sixteen patients presented with

SSNHL aer conrmation with pure tone audiometry.

ere were 11 (68.75%) were male and 5 (31.25%) were

females with male to female ratio of 2.2:1. e age ranges

of the participating patients were 38 years to 72 years

of age with a mean age of the study patients was 48.42

years. ere were 7 patients (43.75%) in the age range of

38 to 50 years and 9 patients (56.25%) in the age range

of 51 to 72 years (Table 1). All of these patients were

positive with RT-PCR for SARS-CoV-2. ere were 9

patients (46.42%) with SSNHL in the le ear, 5 patients

(31.25%) with SSNHL in the right ear and 2 patients

(12.50%) had bilateral sudden SSNHL. All these patients

were presented with symptoms of sudden hearing loss

and heaviness in the aected ear. Out of 16 patients, 5

(31.25%) presented with tinnitus and 3 (18.75%) presented

with vertigo (Table 1). In this study, 13 patients (81.25%)

presented with SSNHL along with respiratory symptoms

such fever, cough, throat pain, rhinorrhea, loss of smell,

dysgeusia and hearing loss whereas 3 patients(18.75%)

were presented with only hearing loss and heaviness in

the ear during stay at the COVID hospital. ere were

no respiratory symptoms among 3 patients (Table 1).

Tuning fork tests were performed in all cases. In tuning

fork test with 512 Hz tuning fork, the Weber test showed

lateralization towards the right side with patients with

le sided hearing loss and towards the le side in case of

right sided hearing loss. e tympanometry test revealed a

type-A tympanogram in 13 patients (81.25%), indicating

normal middle ear whereas the type-C tympanogram was

found in 3 patients (18.75%) which indicates eustachian

tube dysfunction. In this study, 14 (87.50%) showed

unilateral SSNHL and 2 (12.50%) showed bilateral SSNHL.

In this study, 11 patients (68.75%) showed high frequency

hearing loss in pure tone audiometry whereas the rest

5 (31.25%) showed low frequency hearing loss. Out of

the 16 patients, 15 (93.75%) showed reduced amplitude

of the TEOAEs (Table 2). In 10 patients (62.50%) with

SSNHL, MRI with contrast showed enhancement of the

cochlea on the aected side (Fig 2). All the diagnosed

cases of SSNHL were treated with oral prednisolone

1mg/kg/day in the tapering dose for 3 weeks. Along

with oral prednisolone, oral vitamin-B with folic acid

complex and with proton pump inhibitor was taken by

patients daily. As all these patients were at the COVID

hospital and isolation in the home, proper evaluation and

follow up were not done properly. e hearing status of

the patients was obtained by a telephonic conversation

with the patient. ere was the recovery of the hearing

in 9 patients (56.25%) aer appropriate and prompt

treatment. e recovery of hearing loss to normal was

conrmed by pure tone audiometry.

DISCUSSION

COVID-19 is an infection of the respiratory tract

caused by a novel virus called severe acute respiratory

syndrome corona virus 2 (SARS-CoV-2).

Corona viruses

causing COVID-19 are encapsulated or enveloped positive

strand RNA virus which can be classied into four genera

such as alpha, beta, delta and gamma. Out of these four

types, alpha and beta are known to infect human beings.

e rst case of COVID-19 infection was reported in

Wuhan, China in late December 2019 which now covered

all over the world.

By 27

February 2020, more than

82,000 COVID-19 positive cases with death more than

2800 have been reported of which approximately 95%

the positive cases and 97% of deaths were in China.

By March 26

, 2020, there were 462,684 patients with

COVID-19 infections reported in 199 countries.

By the

August 2020, over 1.8 million new cases of COVID-19

and 39000 new death were reported by WHO and this

gives the cumulative total to 21.2 million conrmed

cases of COVID-19 including 761000 deaths.

e novel

SARS-CoV-2 virus is transmitted from one person to

Fig 2. MRI with coronal view in T1 post-

contrast sequence showing increased contrast

enhancement of the right side cochlea (thick

red arrow) and the le side cochlea (thin

red arrow) showing normal enhancement.

Meninges at the base of the temporal lobe

at the right side showing linear enhancement

(yellow arrows).

Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

Swain et al.

Characteristics n=16 Percentage (%)

Gender

Male 11 68.75

Female 5 31.25

Age group

38-50 7 43.75

51-72 9 56.25

Sudden sensorineural hearing loss (SSNHL) 16 100

SSNHL in right ear 5 31.25

SSNHL in left ear 9 56.25

SSNHL in both ear 2 12.5

Tinnitus 5 31.25

Vertigo 3 18.75

Sudden hearing loss with respiratory infections 13 81.25

(Fever, cough, throat pain, throat pain, cough,

rhinorrhea, loss of smell and dysgeusia )

No respiratory symptoms but with hearing loss 3 18.75

and heaviness in the ear

TABLE 1. Outcomes of RAI therapy at the 6 to 9-month follow-up.

TABLE 2. Audiological prole of the COVID-19 patients.

Parameters Number of the patients (n=16) Percentage (%)

Pure tone audiometry

Unilateral SNHL 14 87.50

Bilateral SNHL 2 12.50

Tympanogram

Type A 13 81.25

Type C 3 18.75

TEOAE

Reduced amplitude 15 93.75

Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

Original Article

SMJ

another by respiratory droplets or contact with an infected

person. e symptoms of the COVID-19 infection may

appear aer 2 to 14 days following the exposure (based

on the incubation period of COVID-19 virus). The

clinical presentations of the COVID-19 patients are fever,

cough, fatigue, gastrointestinal symptoms, sore throat,

headache, olfactory and taste dysfunctions.

In this

study, 13 patients (81.25%) presented with SSNHL with

respiratory symptoms such as fever, cough, throat pain,

cough, rhinorrhea, loss of smell and dysgeusia whereas

3 patients (18.75%) were presented with only hearing

loss and heaviness in the ear without any respiratory

symptoms. e elderly patients and the persons with co-

morbid conditions or immunocompromised conditions

are prone to serious outcomes such as acute respiratory

syndrome (ARDS) and cytokine storm.

e neurological

manifestations associated with SARS-CoV-2 infections are

nonspecic symptoms such as loss of smell, loss of taste,

dizziness, ataxia and peripheral nerve involvement. e

etiopathology for SSNHL includes neuritis of the cochlear

nerve by the virus, inammation of the cochlea by viral

infection and the perilymphatic tissues. e evidence of

sensorineural hearing loss (SNHL) was also documented

with infections of certain viruses such as herpes simplex

virus, measles virus, hepatitis virus, rubella virus, mumps

virus, human immunodeciency virus (HIV), Lassa virus

and enteroviruses.

Incidence of SNHL is 12 to 19%

cases in rubella infections, up to 33% in infections with

herpes simplex virus, 0.1 to 3.4% in measles, 0.005 to 4%

in mumps,6 to 23% (asymptomatic patients) to 22- 65%

(symptomatic patients in cytomegalovirus infections and

27.5 to 33.5% in HIV infections.

Certain viruses like

rubella and cytomegalovirus infections cause congenital

SNHL which are not documented in case of COVID-19

infections. ere are three mechanisms associated with the

incidence of SSNHL in viral infections such as: (1) neuritis

caused by viral infection of auditory nerves or cochlea; (2)

viral involvement of the perilymphatic tissues; (3) Stress

response occurred by cross reactions of the antigens of

the inner ear.

Study on the animal was showing viral

infections causing hearing loss through directly aecting

labyrinth or indirectly through cerebrospinal uid.

15,16

any patients develop the SSNHL and seek consultations

at the outpatient department of Otorhinolaryngology,

they should require RT-PCR testing to rule out SARS-

CoV-2 infection. ere are several reports regarding the

neurological involvement by the SARS-CoV-2 infection

but not much report with SSNHL. One study reported

with non-specic neurological symptoms ataxia, dizziness,

olfactory or gustatory dysfunctions and neuralgia due

to peripheral nerve involvement by SARS-CoV-2.

is study tried to nd out the specic SSNHL among

the COVID-19 patients. e better way to study the

etiology is autopsy which seems to provide denite

evidence towards a better understanding of the nerve

involvement by the virus. In past SARS-CoV and Middle

East respiratory syndrome corona virus (MERS-CoV)

outbreak, cerebrospinal uid studies revealed the presence

of the nucleic acid and neural involvement in an autopsy

study.

18,19

Autopsy studies of the patients with SARS-

CoV-2 had shown the hyperemic and edematous brain

tissue along with degeneration of the nerves.

e SARS-CoV-2 enters the airways and invade the

cell by penetrating the angiotensin-converting enzyme

2 (ACE2) receptors at the lungs. Once the cytosolic

pH decreases, the binding of the ACE 2 to the virus

will be easier.

As the cytosolic pH decreases with the

increase of age, the virus can lead to easy and heavy

infections in elderly persons.

e SARS-CoV-2 can

attach to the hemoglobin and penetrate the red blood

cell/erythrocyte.

en this virus can be transported

with erythrocyte or vascular endothelium and aect all

the tissues with ACE2. ere are abundant ACE2 at the

brain and medulla oblongata.

e auditory center is

situated at the temporal lobe of the brain where ACE2

is present. Over expression of ACE2 in the brain except

at the medulla oblongata has a positive eect like anti-

oxidant and anti-inammatory and regulator of the blood

pressure.

But, if the cytosolic pH is less, raised ACE2

leads to an increase in the viral load.

So, the SARS-

CoV-2 infection may progress to more severity. e

virus release excess cytokines at the auditory center of the

brain and its surroundings. So, it can cause permanent

damage to the auditory center of the brain by raising

oxidative damage. If there is excessive activation of the

virus at the auditory center, can cause it hypoxic and

lead to damage. e virus has also nature to cause an

increase in thrombosis risk. SARS-Cov-2 can infect the

veins which drain the auditory center so can make a clot

of these vessels. is clot blocks the blood vessels and

aects the hearing center, leading to ischemic damage.

Because of the impaired vascularity and susceptibility

for thrombosis in elderly age people, hearing problems

may happen by this above mechanism. ere may be

associated with inner ear symptoms like tinnitus and

vertigo may be found. In this study, 5 patients (31.25%)

presented with tinnitus and 3 patients (18.75%) presented

with vertigo.

Tuning fork tests, pure tone audiometry, tympanometry

and Otoacoustic emissions (OAE) were done to evaluate

the SSNHL in our study patients with COVID-19 infection.

e type and degree of hearing loss were assessed by

Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

the tuning fork test and pure tone audiometry. In this

study majority of the cases of SSNHL (68.75%) show

high frequency hearing loss in pure tone audiometry. In

this study, 87.50% patients showed unilateral SSNHL

and 12.50% cases showed bilateral SSNHL. In this study,

11(68.75%) showed high frequency hearing loss in pure

tone audiometry. Tympanometry was done to assess the

middle ear pathology. In this study, 13 patients (81.25%)

showed type-A tympanogram and 3 patients (18.75%)

showed type-C tympanogram. Type-A tympanogram

indicates normal middle ear whereas type-C indicates

eustachian tube dysfunction. e airway infections in

COVID-19 patients specically infections or inammations

at the nasopharynx cause Eustachian dysfunction and

responsible for type-C tympanogram. Otoacoustic emissions

represent a form of energy produced from the outer

hair cells of the cochlea. Otoacoustic emissions can be

spontaneous (SOAEs), evoked by transient stimuli like

clicks or tone bursts (TEOAEs). TEOAEs are not invasive

and can be easily performed. For performing TEOAEs,

the time is short, low cost and high sensitivity.

In this

study, 15 patients (93.75%) showed reduced amplitude

in TEOAE which indicates subtle deterioration of the

outer hair cell functions of the cochlea. e magnetic

resonance imaging (MRI) with the contrast of the brain

and inner ear may show the inammatory changes at the

cochlea and auditory center. Even cochlear ossication

may be found because of the inammation. In this study,

62.50% of patients showed signs of inammation at the

cochlea in MRI. orough investigations should be done

to nd out the exact etiology of the SSNHL and using

other treatment options in COVID-19 positive patients

can prevent such undesirable complications.

It is challenging for a clinician to identify the etiology

as COVID-19 infections for SSNHL and start appropriate

treatment to get maximum clinical recovery with minimal

side eects and complications. Corticosteroid is an important

rst line drug for the treatment of the SSNHL.

In this

study, all the diagnosed cases of SSNHL were treated with

oral prednisolone in the tapering dose and vitamin-B

with folic acid complex and with proton pump inhibitor

daily. However, the use of the corticosteroids in the

SARS-CoV-2 infections as in other viral infections,

can lead to increased severity of the infection and cause

delayed clearance of the viral infections.

In this study 9

patients (56.25%) showed complete resolution of hearing

loss/normal hearing and became normal with treatment

by corticosteroids. In non-COVID patients, the rate of

recovery from SSNHL aer treatment in the rst week

of disease onset, within 2 weeks and beyond 3 months

is 87%,52% and <10% respectively.

27,28

CONCLUSION

Patients with COVID-19 infections have a chance of

hearing loss specically sudden sensorineural hearing loss.

In our study, the incidence of SSNHL among COVID-19

patients was 2.45%, where the majority of them were

associated with respiratory symptoms. e exact role of

the pathogenesis of the SSNHL in COVID-19 infections

is not well dened. We would like to recommend routine

screening of all the COVID-19 positive cases with pure

tone audiometry, tympanometry and otoacoustic

emission for early diagnosis of the SSNHL and prompt

treatment or rehabilitation. In our study, 56.25% patients

with SSNHL recovered with prompt and appropriate

treatment. Awareness regarding SSNHL in COVID-19

patients is oen crucial in the current pandemic. Early

identication of the COVID-19 patients with isolation

and early initiation of the targeted treatment for the

patients helps to reduce the incidence of the SNHL. A

high level of vigilance and assessment of the sudden

sensorineural hearing loss in COVID-19 patients require

urgent treatment for the revival of hearing. e sudden

SNHL may be the only symptom in COVID-19 patients.

Awareness of this presentation in COVID-19 patients

is oen crucial in this current pandemic. Isolation ad

early treatment for COVID-19 patients may give a good

outcome. is study surely brings awareness among

the clinicians and researchers to look for SARS-CoV-2

infections in patients with SSNHL.

Study limitation

is study has a relatively small sample size due to

the rarity of the clinical outcome (sudden sensorineural

hearing loss) in COVID-19 infections which may limit

the outcome of the above interpretation. Although the

sample size is small, the result of this study is an important

message for the public health point of view to isolate

the SSNHL with COVID-19 patients. However, the

development of the SSNHL in COVID-19 patients in

this study will surely encourage further research.

Conict of interest: NIL

REFERENCES

1. World Health Organization fact sheet. Deafness and hearing loss.

In: World Health Fact Sheets. Geneva: World Health Organization;

1 March 2020. Available from: https://www.who.int/news-room/

fact-sheets/detail/deafness-and-hearing-loss

2. Wang W, Tang J, Wei F. Updated understanding of the outbreak

of 2019 novel corona virus (2019-nCoV) in Wuhan, China. J

Med Virol 2020;92:441-47.

3. Swain SK, Das A, Sahu MC, Das R. Neonatal hearing screening:

Our experiences at a tertiary care teaching hospital of eastern

India. Pediatric Polska 2017;92:711-5.

Swain et al.

Volume 73, No.2: 2021 Siriraj Medical Journal

https://he02.tci-thaijo.org/index.php/sirirajmedj/index

Original Article

SMJ

4. Leung AK, Hon KL, Leong KF, Sergi CM. Measles: a disease

oen forgotten but not gone. Hong Kong Med J 2018;24:512-

20.

5. Weiss D, Böcker AJ, Koopmann M, Savvas E, Borowski M,

Rudack C. Predictors of hearing recovery in patients with

severe sudden sensorineural hearing loss. J Otolaryngol Head

Neck Surg 2017;46:27.

6. de Wilde AH, Snijder EJ, Kikkert M, van Hemert MJ. Host

factors in corona virus replication. Curr Top Microbiol Immunol

2018;419:1-42.

7. Swain SK, Das S, Padhy RN. Performing tracheostomy in

intensive care unit-A challenge during COVID-19 pandemic.

Siriraj Med J 2020;72:436-42.

8. Wu A, Mc Googan JM. Characteristics of and important lessons

from the corona virus disease 2019 (COVID-19) outbreak in

China: summery of a report 72,314 cases from Chinese Center

for Disease Control and Prevention. JAMA 2020;323:1239-42.

9. Corona virus disease 2019 (COVID-19) situation report-66. World

Health Organization. March 26, 2020. Available from: https://www.

who.int/docs/defaultsource/coronavirus/situation-reports/

20200326-sitrep-66-covid-19

10. World Health Organization. Corona virus disease (COVID-19):

weekly epidemiological, update 1.2020.

11. Yan-Rong Guo,Qing-Dong Cao,Zhong-Si Hong,Yuan-Yang

Tan,Shou-Deng Chen,Hong-Jun Jin,et al. e origin, transmission

and clinical therapies on corona virus disease 2019 (COVID-19)

outbreak – an update on the status. Mil Med Res 2020;7:11.

12. Mateer EJ, Huang C, Shehu NY, Paessler S. Lassa fever-induced

sensorineural hearing loss: a neglected public health and social

burden. PLoS Negl Trop Dis 2018;12: e0006187.

13. BCohen BE, Durstenfeld A, Roehm PC. Viral Causes of Hearing

Loss: A Review for Hearing Health Professionals. Trends in

Hearing 2014;18:1-17.

14. Wilson WR. e relationship of the herpes virus family to

sudden hearing loss: a prospective clinical study and literature

review. Laryngoscope 1989;96:870-7.

15. Esaki S, Goshima F, Kimura H, Ikeda S, Katsumi S, Kabaya K,

et al. Auditory and vestibular defects induced by experimental

labyrinthitis following herpes simplex virus in mice. Acta

Otolaryngol 2011;131:684-91.

16. Cashman KA, Wilkinson ER, Zeng X, Cardile AP, Facemire PR,

Bell TM, et al. Immune-mediated systemic vasculitis as the

proposed cause of sudden-onset sensorineural hearing loss

following lassa virus exposure in cynomolgus macaques. MBio

2018;9:1896-918.

17. Mao L, Jin H, Wang M, Hu Y, Chen S, He Q, Chang J, Hong C,

Zhou Y, Wang D, Miao X. Neurologic manifestations of

hospitalized patients with Coronavirus Disease 2019 in Wuhan,

China. JAMA Neurol 2020;77:683-90.

18. Arabi YM, Balkhy HH, Hayden FG, Bouchama A, Luke T,

Baillie JK, et al. Middle East respiratory syndrome. N Engl J

Med 2017;37:584-94.

19. Desforges M, Favreau DJ, Brison E, Desjardins J, Meessen-

Pinard M, Jacomy H, et al. Human corona virus: respiratory

pathogens revisited as infectious neuro-invasive, neurotropic,

and neurovirulent agents. CRC Press, 2013.p.93-122.

20. National Health Commission & National Administration of

Traditional Chinese Medicine on March 2, 2020. Diagnosis and

Treatment Protocol for Novel Coronavirus Pneumonia (Trial

Version 7). Chinese Medical Journal 2020;133:1087-95. [Cited

03 March 2020]. Available from: https://journals.lww.com/cmj/

fulltext/2020/05050/diagnosis_and_treatment_protocol_for_

novel.13.aspx

21. Cure E, Cure CM. Comment on “Organ protective eect of

angiotensin-converting enzyme 2 and its eect on the prognosis

of COVID-19”. J Med Virol 2020;10.1002/jmv.25848. doi:10.1002/

jmv.25848. Online ahead of print.

22. Liu W, Li H. COVID-19: Attacks the 1-Beta Chain of Hemoglobin

and Captures the Porphyrin to Inhibit Human Heme Metabolism.

Chem Rxiv 2020;10:1-23.

23. Krasniqi S, Daci A. Role of the angiotensin pathway and its

target therapy in epilepsy management. Int J Mol Sci 2019;20:726.

24. Paludetti G, Ottaviani F, Fetoni AR, Zuppa AA, Tortorolo G.

Transient evoked Otoacoustic emissions(TEOAEs) in newborns:

normative data. Int J Pediatr Otorhinolaryngol 1999;47:235-41.

25. Hara JH, Zhang JA, Gandhi KR, Flaherty A, Barber W, Leung

MA, et al. Oral and intratympanic steroid therapy for idiopathic

sudden sensorineural hearing loss. Laryngoscope Investig

Otolaryngol 2018;3:73-77.

26. World Health Organization. Clinical management of severe acute

respiratory infection (SARI) when COVID-19 disease is suspected:

interim guidance, 13 March 2020. World Health Organization.

Available from: https://apps.who.int/iris/handle/10665/331446?

search-result=true&query=10665%2F331446&scope=&rpp=

10&sort_by=score&order=desc

27. Zadeh MH, Storper IS, Spitzer JB. Diagnosis and treatment

of suddenonset sensorineural hearing loss: a study of 51 patients.

Otolaryngol Head Neck Surg 2003;128:92-98.

28. Nosrati-Zarenoe R, Hultcrantz E. Corticosteroid treatment of

idiopathic sudden sensorineural hearing loss: randomized

triple-blind placebo-controlled trial. Otol Neurotol 2012;33:

523-31.