A.J. Fasunla1, Y. Thairu2, H. Salami3 and T.S. Ibekwe4
- Department of Otorhinolaryngology, University College Hospital and College of Medicine, University of Ibadan, Ibadan, Nigeria.
- Dept. of Microbiology, University of Abuja, and University of Abuja Teaching Hospital, Abuja, Nigeria.
- Department of Nursing, University of Abuja Teaching Hospital, Gwagwalada, Abuja, Nigeria.
- Department of Otorhinolaryngology, University of Abuja and University of Abuja Teaching Hospital, Abuja, Nigeria.
Introduction: The pathophysiology of COVID-19 is evolving. We investigated self-reported sudden loss of sense of smell and taste, and otologic disorders among COVID-19 patients.
Methods: This was a case-control olfaction, gustation and otology study of COVID-19 RT-PCR tested adults. The study took place at the isolation centres for COVID-19 positive individuals in Abuja and Ibadan, among the epicentres of the disease in Nigeria. The participants were 46 COVID-19 positive adults and 46 COVID-19 negative adults. They responded to a validated online questionnaire-based on olfactory, gustatory and auditory loss. Chi-square tests and correlation analysis was done. Level of significance was at P<0.05.
Results: Among cases, sudden loss of smell, taste and hearing were reported by 14 (30.4%), 8 (17.4%) and 5 (10.9%) cases respectively during the COVID19 infection. First symptom was loss of smell in 7 (15.2%) and loss of taste in 2 (4.3%) cases. The controls did not present with any of the symptoms. There was no significant correlation between loss of smell and age (r = 0.023, p=0.879); sex (r = -0.132, p=0.382) and co-morbidities (r = -0.028, p = 0.857). Similarly, there was no significant correlation between loss of taste and age (r = 0.052, p = 0.732); sex (0.040, p = 0.792) and co-morbidities (r = -0.014, p = 0.925).
Conclusion: Sudden loss of smell and taste are commoner among COVID – 19 positive adults than those without the infection in Nigeria. There is evidence of associated reduction in hearing acuity but further study with objective audiometric testing is recommended.
Keywords: Anosmia, Ageusia, Coronavirus, Chemosensory dysfunction, Hearing loss, Otology, COVID-19 pandemic, SARS-CoV-2
Prof. T.S. Ibekwe
Department of Otorhinolaryngology,
University of Abuja and
University of Abuja Teaching Hospital,
Corona virus disease-2019 (COVID-19) is an RNAviral syncytial respiratory disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). COVID-19 was first reported in Wuhan, China at the twilight of 2019 and declared a pandemic by the World Health Organisation (WHO) in March 2020. The epidemiology and management of this illness is still evolving resulting in the recent recognition of smell and taste disorders as “minor” clinical presentations in COVID-19 patients by the WHO, Centres for Disease Control and Prevention (CDC) and other global health organizations.1
Coronavirus is a highly virulent and contagious organism with an incubation period of about 2 weeks within which asymptomatic patients can transmit the disease. It is difficult to identify carriers and asymptomatic patients during the incubation period hence the prescribed stringent measures such as social distancing, hand washing, wearing of face masks, etc., to prevent, control, and contain its spread.2
Common symptoms of COVID-19 were fever, difficulty with breathing and cough. Early presentations with loss of smell (anosmia) and/or taste (ageusia) in mild and moderate cases of COVID-19 could be a red-flag and veritable tool for early diagnosis.3 It is true that several diseases caused by viruses such as Herpes Simplex, Rhinoviruses, Measles, Epstein-Barr, Chicken pox and other Coronaviruses present with varying degrees of anosmia, rhinorrhoea and nasal blockage.4,5 Sometimes these triad is associated with ageusia. However, the anosmia and ageusia associated with COVID-19 is typically without rhinorrhoea or nasal blockage.6 In addition, patients with COVID-19 have more than 10-fold chance of developing ageusia and anosmia compared to other flu-like diseases.7 Variable reports on anosmia and ageusia in COVID19 patients were documented in different parts of the world with the exception of Africa.3,5-9
SARS-CoV-2 infects human through the nasal cavity, oral cavity and conjunctiva. The respiratory epithelium and its supporting olfactory cells are rich in Angiotensin Converting Enzyme-2 (ACE2). This feature makes them serve as reservoir for the replication of the SARSCOV-2 virus because the spike (S) proteins on their cell walls called protease transaminase protease serine2 (TMPRSS2) have strong affinity for ACE2.3 This interaction initiates an inflammatory process in the olfactory and respiratory epithelium. Contiguous anatomical relationship and similarity in the epithelial cells of the nasal cavities/nasopharynx, the Eustachian tube and the middle ear strongly suggest a middle ear cleft susceptibility to COVID-19. Above all, SARSCOV-2 has been isolated in the middle ear spaces and mastoid cavities of COVID-19 patients.10 The exact pathophysiology of loss of smell and taste in COVID19 is not known. However, nasal mucosa inflammation, damage to olfactory receptors and infection of the olfactory bulb, nerve and smell centre in the brain have been suggested as the possible mechanisms.11-13 Any or all of these three mechanisms may be possible for loss of smell and by extension taste in the COVID-19 though subject to further investigation. To the best of our knowledge, there has not been any clinical report on otologic manifestations
of COVID-19 at the time of design of this research. To this end, we set out to explore the features of selfreported anosmia, ageusia and otological disorders among COVID-19 patients.