Pathophysiological relationship between COVID-19 and olfactory dysfunction: A systematic review

Lima, Mateus Henrique de Las Casas; Cavalcante, Ana Luiza Brusiquesi; Leão, Sydney Correia

doi:10.1016/j.bjorl.2021.04.001

Cited by 28 publications

(23 citation statements)

References 40 publications

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“…ACE-2 is widely distributed in the cell membranes of many organs and there is a high density of ACE-2 in the nasal and oral mucosa. The link between the spike protein and ACE-2 receptors is aided by a protease present in the surface of the target cell called TMPRSS2 [35].…”

Section: Discussionmentioning

confidence: 99%

“…One suggested hypothesis on the pathophysiology of anosmia and/or dysgeusia regards the direct damage SARS-CoV-2 may cause to the olfactory receptors present in the nasal mucosa and the gustatory receptors present in the tongue [35,36]. Olfactory and gustatory receptors bind the smell and taste molecules.…”

Section: Discussionmentioning

confidence: 99%

“…Recent data provided by experiments on mice have shown that the virus does not cause direct damage to the neurons, as they do not express ACE-2 receptors. Instead, the virus most likely alters the function of the olfactory epithelium by damaging the sustentacular cells and Bowman cells [35]. The olfactory epithelium contains the cells which provide metabolic support to olfactory neurons and present similar levels of ACE-2 receptors to those of the respiratory tract.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Olfactory Dysfunction in COVID-19 Patients Who Do Not Report Olfactory Symptoms: A Pilot Study with Some Suggestions for Dentists

Favero

Hajrulla

Bordin

et al. 2022

IJERPH

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Background: Smell and taste dysfunction are frequently reported by SARS-CoV-2 positive patients. The degree of olfactory and gustatory dysfunction varies from a very mild reduction to their complete loss. Several studies have been performed to determine their prevalence in COVID-19 patients, mostly using subjective measurement methods. The literature lacks long-term studies regarding duration and recovery. Methods: We assessed olfactory performance, using the Sniffin’ Sticks olfactory test, in a group of patients who had not reported olfactory dysfunction, around 131 days after their COVID-19 diagnosis. Results: 11 out of 20 subjects showed no olfactory reduction (65%), while 9 subjects showed reduced TDI score (45%). A total of 13 subjects (65%) scored above the cutoff point for Threshold, 16 subjects (80%) scored above the cutoff point for discrimination and 13 subjects (65%) scored above the cutoff point for identification. Conclusion: Objective measurement methods of olfactory performance show a higher prevalence of olfactory reduction compared to patients’ self-reported questionnaires. Olfactory dysfunction can last even months after its onset and because of its high prevalence, it could be a screening symptom for suspect COVID-19 cases.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Olfactory Dysfunction in COVID-19 Patients Who Do Not Report Olfactory Symptoms: A Pilot Study with Some Suggestions for Dentists

Favero

Hajrulla

Bordin

et al. 2022

IJERPH

View full text Add to dashboard Cite

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“…The leading mechanism involved in the development of anosmia is through damage of the olfactory epithelium, affecting mainly non-neuronal cells. Nonetheless, neuronal cells can also be involved, worsening the olfactory function 32 .…”

Section: Discussionmentioning

confidence: 99%

How COVID-19 brought smell disorders in the spotlight

Neagu

Sarafoleanu

2021

Romanian Journal of Rhinology

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The rapid spread of the COVID-19 infection required prompt recognition and immediate isolation of patients. In the evolution of the disease various symptoms were indicated as suggestive of a SARS-CoV-2 infection, among them being also described anosmia and ageusia. In order to review how olfactory disorders are related to COVID-19 disease, we carried out an analysis by searching PubMed, Science Direct, Springer, and LILACS. The research was made using MeSH descriptors and the Boolean operator, “AND”, for the terms “olfactory disorders” or “olfactory dysfunction” or “anosmia” or “neurologic manifestations” or “ENT symptoms” AND “COVID-19” or “SARS-CoV-2” or “coronavirus infections”, with a filter on the publication date set for 01.01.2020 – 18.06.2021. A total of 956 articles were found in the databases, out of which 14 were included in the study. The statistics suggest that alterations of the chemosensory function are strongly correlated with COVID-19, although the exact pathophysiologic mechanism is not well established. Symptomatology suggestive of chemosensory dys-function (smell primarily and then taste alterations) elevate the degree of suspicion of a SARS-CoV-2 infection and they commend prompt isolation and surveillance measurements.

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“…In practice SARS-CoV-2 enters the airways and accumulates in the olfactory support cells, in particular in the sustentacular cells which, in contrast with neurons, abundantly express ACE2. These support cells are metabolically and functionally associated with olfactory neurons and with the transmission of the odour signal [ 71 ]. Therefore, when their function is interrupted, olfaction is seriously compromised.…”

Section: Host-related Pathogenetic Factorsmentioning

confidence: 99%

SARS-CoV-2 Infection and Taste Alteration: An Overview

Scotto

Fazio

Muzio

et al. 2022

Life

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Since the worldwide spread of SARS-CoV-2 infection, the management of COVID-19 has been a challenge for healthcare professionals. Although the respiratory system has primarily been affected with symptoms ranging from mild pneumonia to acute respiratory distress syndrome, other organs or systems have also been targets of the virus. The mouth represents an important route of entry for SARS-CoV-2. Cells in the oral epithelium, taste buds, and minor and major salivary glands express cellular entry factors for the virus, such as ACE2, TMPRSS2 and Furin. This leads to symptoms such as deterioration of taste, salivary dysfunction, mucosal ulcers, before systemic manifestation of the disease. In this review we report and discuss the prevalence and socio-demographics of taste disturbances in COVID-19 patients, analysing the current international data. Importantly, we also take stock of the various hypothesized pathogenetic mechanisms and their impact on the reported symptoms. The literature indicated that COVID-19 patients frequently present with gustatory dysfunction, whose prevalence varies by country, age and sex. Furthermore, this dysfunction also has a variable duration in relation to the severity of the disease. The pathogenetic action is intricately linked to viral action which can be expressed in several ways. However, in many cases these are only hypotheses that need further confirmation.

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Pathophysiological relationship between COVID-19 and olfactory dysfunction: A systematic review

Cited by 28 publications

References 40 publications

Olfactory Dysfunction in COVID-19 Patients Who Do Not Report Olfactory Symptoms: A Pilot Study with Some Suggestions for Dentists

Olfactory Dysfunction in COVID-19 Patients Who Do Not Report Olfactory Symptoms: A Pilot Study with Some Suggestions for Dentists

How COVID-19 brought smell disorders in the spotlight

SARS-CoV-2 Infection and Taste Alteration: An Overview

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