الفهرس 
ANATOMY OF OLFACTORY SYSTEMOnly 14 pages are availabe for public view
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Abstract
B
ecause of the rapid spreading of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the Coronavirus disease 2019 (COVID-19) outbreak was characterized as a pandemic by the WHO on March 11, 2020. Olfactory and gustatory dysfunction have recently been reported to be higher in home-quarantined, young, and female patients. Screening for loss of taste or smell in otherwise asymptomatic individuals may be an effective strategy to stop transmission early in the disease. Additionally, the presence of anosmia and/or ageusia in a patient presenting with nonspecific respiratory symptoms could help to rule out infection with influenza in the upcoming flu season. we conducted a systematic review and meta-analysis to estimate the prevalence of OGDs among patients infected with COVID-19.
Following the PRISMA statement guidelines, we conducted this systematic review and meta-analysis according to the Cochrane handbook of systematic reviews of intervention. We searched PubMed, Scopus, Cochrane, and Web of Science, Embase, and Science Direct till December 2021 with relevant keywords. We included the whole clinical studies assessing olfactory and/or gustatory dysfunctions (OGD) in patients with COVID-19, studies including patients with a confirmed diagnosis of COVID-19 by a positive result of RT-PCR were included, studies that assessed the OGD by either subjective evaluation were also included, studies written in English languages only, all of the studies must have been written in English as a full-text manuscript, double or single-arm designs. The risk of bias was evaluated following the modified Newcastle-Ottawa Scale (NOS) for non-randomized studies adapted for cross-sectional studies. We obtained data from text, tables, figures (using graph grabber version 2.0), and supplementary data. Finally, we conducted this meta-analysis by using Open Meta Analyst (OMA) (Computer program).
A total of 12 studies were finally included for the final qualitative and quantitative analysis illustrating the association and the relationship between COVID-19 infection and olfactory and gustatory functions. The mean age of the participants was 49.12 years. The pooled analysis of the included studies showed a significant association of positive results between OGD and COVID-19 infection. Also, the analysis showed a significant association of positive results between either isolated olfactory or gustatory dysfunction and COVID-19 infection.
Regarding the association between gustatory dysfunction in COVID-19 patients versus (Acute respiratory infection) ARI patients with no detectable virus, the analysis showed a significant difference between COVID-19 patients and ARI patients with no detectable virus regarding the gustatory dysfunction meaning there is a high association between gustatory dysfunction and COVID-19 patients other than ARI patients with no detectable virus. Finally, the pooled analysis of the included studies showed a significant difference between COVID-19 patients and ARI patients with other respiratory viruses (ORV) in terms of OGD.
OGDs have a high prevalence among COVID-19 patients and may represent early symptoms. Although the prevalence rates are variable, olfactory and gustatory dysfunction are commonly reported in patients with COVID-19 and noted as significant symptoms. consideration of OGDs as part of the screening and diagnostic approaches for COVID-19 could help improve case detection. Increased awareness of this fact may encourage earlier diagnosis and treatment of COVID-19, as well as limit the viral spread. Patients presenting with an acute respiratory infection (ARI) should be assessed for olfactory and gustatory functions. Finally, based on the available evidence, there are regional and chronological differences in the prevalence rates of olfactory and gustatory dysfunction. Future studies, particularly those that document the temporal relationship in the onset of these 2 symptoms, are needed.