Post-COVID Syndrome in Otorhinolaryngology: A Systematic Review

Abstract

Background: The novel virus SARS-CoV-2 which is the cause for coronavirus-19 disease (widely known as COVID-19), has shifted health and healthcare worldwide. With the majority of COVID-19 cases having mild to moderate symptoms, and with improvement in treatment and survival of severe disease, there has been a rise in the number of patients presenting with prolonged, recurrent or new symptoms long after the time frame of active disease. This phenomenon has been given various terms which include post-COVID syndrome. Post-COVID syndrome like acute disease has various clinical presentations that involve multiple systems in the body which include the ear, nose and throat. Due to the substantial increase in this population of patients with ongoing COVID-19 symptoms, the current focus is towards identifying and managing these patients early so as to improve outcomes and quality of life. Objectives: The aim of this systematic review was to bring awareness to post-COVID syndrome in the context of otorhinolaryngology with a description of the demographics, clinical manifestations and identifiable predisposing factors. The secondary objectives were to describe special investigations used for diagnosis and management of patients with post-COVID syndrome in otorhinolaryngology. Methods: A systematic review of all the available published literature (systematic reviews, cohort studies, case series and case studies) was conducted. The databases searched were PubMed, The Cochrane Database of Systematic Reviews, EMBASE, and Google Scholar. The search terms used were “post-COVID syndrome” OR ‘’post-acute COVID-19’’ OR ‘’long COVID’’ AND “chemoreceptor dysfunction” OR “Otology” OR “Rhinology” OR “Laryngology”. The search included articles from January the 1st 2020 to the 31st of July 2021. A total number of 13 561 articles were found of which 25 articles met the inclusion criteria. The systematic review was a retrospective study of information already available in the public domain. Ethics clearance was received from the University of the Witwatersrand Human Research Ethics Committee (medical). Results: A total of 25 studies were included in the systematic review with a total of 1041 patients presenting with otorhinolaryngological symptoms associated with COVID-19. Patients who presented with symptoms in the post-acute COVID-19 period (more than 4 weeks) were 383 in total. The vast majority presented with chemosensory dysfunction (olfactory +/- gustatory) accounting for 82,5% (n=316). Patients with audiovestibular symptoms (sensorineural hearing loss, tinnitus and/or vertigo) accounted for 7,6% (n=29) and patients with dysphonia 9,9% (n=38). Fifteen percent of cases (152/1041) presented with otorhinolaryngological symptoms beyond 12 weeks (post-COVID syndrome). Chemosensory dysfunction still accounted for most cases in this group with 80,9% (n=123), 8,6% (n=13) had persistent or residual audiovestibular symptoms (sensorineural hearing loss, tinnitus, vertigo) and 10,5% (n=16) had persistent dysphonia. The limitations of the systematic review were the lack of high-quality data due to the novelty of COVID-19, the risk of bias of individual studies and the heterogenous findings and outcomes. Conclusion: Post-COVID syndrome like acute COVID-19 manifests in multiple systems in the body which include the ear, nose and throat. Otorhinolaryngological symptoms that this population presents with include chemosensory dysfunction, audiovestibular dysfunction and dysphonia. Olfactory dysfunction is the dominant presentation with more data available in the literature as it presents more commonly. There is need for larger and more detailed future studies with focus on identification of specific risk factors that predispose individuals to post-COVID syndrome with the goal of improving outcomes and preventing long-term disability.