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Molecular Neurobiology Feb 2021COVID-19 is a highly infectious viral disease caused by the novel coronavirus SARS-CoV-2. While it was initially regarded as a strictly respiratory illness, the impact... (Review)
Review
COVID-19 is a highly infectious viral disease caused by the novel coronavirus SARS-CoV-2. While it was initially regarded as a strictly respiratory illness, the impact of COVID-19 on multiple organs is increasingly recognized. The brain is among the targets of COVID-19, and it can be impacted in multiple ways, both directly and indirectly. Direct brain infection by SARS-CoV-2 may occur via axonal transport via the olfactory nerve, eventually infecting the olfactory cortex and other structures in the temporal lobe, and potentially the brain stem. A hematogenous route, which involves viral crossing of blood-brain barrier, is also possible. Secondary mechanisms involve hypoxia due to respiratory failure, as well as aberrant immune response leading to various forms of encephalopathy, white matter damage, and abnormal blood clotting resulting in stroke. Multiple neurological symptoms of COVID-19 have been described. These involve anosmia/ageusia, headaches, seizures, mental confusion and delirium, and coma. There is a growing concern that in a number of patients, long-term or perhaps even permanent cognitive impairment will persist well after the recovery from acute illness. Furthermore, COVID-19 survivors may be at increased risk for developing neurodegenerative diseases years or decades later. Since COVID-19 is a new disease, it will take months or even years to characterize the exact nature, scope, and temporal extent of its long-term neurocognitive sequelae. To that end, rigorous and systematic longitudinal follow-up will be required. For this effort to succeed, appropriate protocols and patient registries should be developed and put in place without delay now.
Topics: Anosmia; Blood-Brain Barrier; Brain; COVID-19; Coma; Delirium; Headache; Humans; Seizures
PubMed: 32990925
DOI: 10.1007/s12035-020-02152-5 -
Ear, Nose, & Throat Journal May 2024The pandemic has affected over 182 million coronavirus disease 2019 (COVID-19) cases worldwide. Accumulated evidence indicates that anosmia is one of the significant... (Review)
Review
OBJECTIVES
The pandemic has affected over 182 million coronavirus disease 2019 (COVID-19) cases worldwide. Accumulated evidence indicates that anosmia is one of the significant characteristics of COVID-19 with a high prevalence. However, many aspects of COVID-19-induced anosmia are still far from being fully understood. The purpose of this review is to summarize recent developments in COVID-19-induced anosmia to increase awareness of the condition.
METHODS
A literature search was carried out using the PubMed, Embase, Web of Science, and Scopus. We reviewed the latest literature on COVID-19-induced anosmia, including mechanisms of pathogenesis, olfactory testing, anosmia as predictive tool, pathological examinations, imaging findings, affected factors, co-existing diseases, treatments, prognosis, hypothesis theories, and future directions.
RESULTS
The possible pathogenesis of COVID-19-induced anosmia may involve inflammation of the olfactory clefts and damage to the olfactory epithelium or olfactory central nervous system by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The D614G spike variant may also play a role in the increased number of anosmia patients. Anosmia may also be an essential indicator of COVID-19 spread and an early indicator of the effectiveness of political decisions. The occurrence and development of COVID-19-induced anosmia may be influenced by smoking behaviors and underlying diseases such as type 2 diabetes, gastroesophageal disorders, and rhinitis. Most patients with COVID-19-induced anosmia can fully or partially recover their olfactory function for varying durations. COVID-19-induced anosmia can be treated with various approaches such as glucocorticoids and olfactory training.
CONCLUSION
Anosmia is one of the main features of COVID-19 and the underlying disease of the patient may also influence its occurrence and development. The possible pathogenesis of COVID-19-induced anosmia is very complicated, which may involve inflammation of the olfactory clefts and damage to the olfactory epithelium or olfactory central nervous system.
Topics: COVID-19; Humans; Anosmia; SARS-CoV-2; Olfactory Mucosa; Olfaction Disorders
PubMed: 34587819
DOI: 10.1177/01455613211048998 -
Pediatric Allergy and Immunology :... Jan 2022More than a year and a half after the beginning of the coronavirus disease 2019 (COVID-19) pandemic, symptoms, such as loss of smell and taste (anosmia and ageusia,...
More than a year and a half after the beginning of the coronavirus disease 2019 (COVID-19) pandemic, symptoms, such as loss of smell and taste (anosmia and ageusia, respectively), remain difficult to characterize and quantify, especially in children, since no validated tests to assess these disorders are available. However, these symptoms can also be seen in children, although less frequently than observed in the adult population. In this article, we present the results of a national survey that collected the responses of 267 Italian pediatricians on the presence of anosmia and ageusia in children affected by COVID-19. These data were then compared with existing literature.
Topics: Adult; Ageusia; Anosmia; COVID-19; Child; Humans; Pandemics; SARS-CoV-2
PubMed: 35080301
DOI: 10.1111/pai.13644 -
Multiple Sclerosis (Houndmills,... Dec 2020
Topics: Anosmia; Aquaporin 4; Autoantibodies; Humans; Neuromyelitis Optica
PubMed: 32228208
DOI: 10.1177/1352458520912380 -
MMW Fortschritte Der Medizin May 2022
Topics: Anosmia; COVID-19; Dermatologic Agents; Glucocorticoids; Humans; Olfaction Disorders; Smell
PubMed: 35513640
DOI: 10.1007/s15006-022-1124-4 -
Frontiers in Bioscience (Landmark... Sep 2022Coronavirus disease 2019 (COVID-19) is a respiratory illness that started and rapidly became the pandemic of the century, as the number of people infected with it... (Review)
Review
Coronavirus disease 2019 (COVID-19) is a respiratory illness that started and rapidly became the pandemic of the century, as the number of people infected with it globally exceeded 253.4 million. Since the beginning of the pandemic of COVID-19, over two years have passed. During this hard period, several defies have been coped by the scientific society to know this novel disease, evaluate it, and treat affected patients. All these efforts are done to push back the spread of the virus. This article provides a comprehensive review to learn about the COVID-19 virus and its entry mechanism, its main repercussions on many organs and tissues of the body, identify its symptoms in the short and long terms, in addition to recognize the role of diagnosis imaging in COVID-19. Principally, the quick evolution of active vaccines act an exceptional accomplishment where leaded to decrease rate of death worldwide. However, some hurdels still have to be overcome. Many proof referrers that infection with CoV-19 causes neurological dis function in a substantial ratio of influenced patients, where these symptoms appear severely during the infection and still less is known about the potential long term consequences for the brain, where Loss of smell is a neurological sign and rudimentary symptom of COVID-19. Hence, we review the causes of olfactory bulb dysfunction and Anosmia associated with COVID-19, the latest appropriate therapeutic strategies for the COVID-19 treatment (e.g., the ACE2 strategy and the Ang II receptor), and the tests through the follow-up phases. Additionally, we discuss the long-term complications of the virus and thus the possibility of improving therapeutic strategies. Moreover, the main steps of artificial intelligence that have been used to foretell and early diagnose COVID-19 are presented, where Artificial intelligence, especially machine learning is emerging as an effective approach for diagnostic image analysis with performance in the discriminate diagnosis of injuries of COVID-19 on multiple organs, comparable to that of human practitioners. The followed methodology to prepare the current survey is to search the related work concerning the mentioned topic from different journals, such as Springer, Wiley, and Elsevier. Additionally, different studies have been compared, the results are collected and then reported as shown. The articles are selected based on the year (i.e., the last three years). Also, different keywords were checked (e.g., COVID-19, COVID-19 Treatment, COVID-19 Symptoms, and COVID-19 and Anosmia).
Topics: Angiotensin-Converting Enzyme 2; Anosmia; Artificial Intelligence; COVID-19; Humans; Vaccines; COVID-19 Drug Treatment
PubMed: 36224026
DOI: 10.31083/j.fbl2709276 -
Journal of Medical Virology Apr 2021Various new clinical signs and symptoms, such as dysfunction of smell (anosmia) and taste (dysgeusia) have emerged ever since the coronavirus disease 2019 (COVID-19)...
Various new clinical signs and symptoms, such as dysfunction of smell (anosmia) and taste (dysgeusia) have emerged ever since the coronavirus disease 2019 (COVID-19) pandemic begun. The objective of this study was to identify the clinical presentation and factors associated with 'new loss/change of smell (anosmia) or taste (dysgeusia)' at admission in patients positive by real time polymerase chain reaction for SARS-CoV-2 infection. All adult COVID-19 patients with new onset anosmia or dysgeusia at admission were included in study group. Equal number of age and gender matched COVID-19 patients without anosmia or dysgeusia at admission were included in the control group. A total of 261 COVID-19 patients were admitted during the study period of which 55 (21%) had anosmia and or dysgeusia. The mean (SD) age was 36 (13) years and majority were males (58%, n = 32). Comorbidity was present in 38% of cases (n = 21). Anosmia and dysgeusia were noted in more than 1/5th of the cases. Anosmia (96%, n = 53) was more common than dysgeusia (75%, n = 41). Presence of both ansomia and dysgeusia was noted in 71% of patients (n = 39). On comparing the cases with the controls, on univariate analysis, fever (higher in cases), rhinitis (lower in cases), thrombocytopenia, elevated creatinine and bilirubin (all higher in cases) were significantly associated with anosmia or dysgeusia. On multivariate analysis, only rhinitis (odds ratio [OR]: 0.28; 95% confidence interval [CI]: 0.09-0.83; p = .02) thrombocytopenia (OR: 0.99; 95% CI: 0.99-0.99; p = .01) and elevated creatinine (OR: 7.6; 95% CI: 1.5-37.6; p = .01) remained significant. In this retrospective study of COVID-19 patients, we found anosmia and dysgeusia in more than 1/5th of the cases. Absence of rhinitis, low platelet counts and elevated creatinine were associated with anosmia or dysgeusia in these patients.
Topics: Adult; Anosmia; COVID-19; Case-Control Studies; Dysgeusia; Female; Humans; India; Male; Middle Aged; Multivariate Analysis; Odds Ratio; Pandemics; Platelet Count; Real-Time Polymerase Chain Reaction; Retrospective Studies; Rhinitis; SARS-CoV-2; Thrombocytopenia
PubMed: 33417259
DOI: 10.1002/jmv.26784 -
The Journal of Laryngology and Otology Mar 2022
Topics: Anosmia; COVID-19; Cholesteatoma, Middle Ear; Female; Humans; Maxillary Sinus; Neoplasms; Otosclerosis; Pregnancy; Therapeutic Irrigation
PubMed: 35285793
DOI: 10.1017/S0022215122000688 -
MMW Fortschritte Der Medizin May 2023
Topics: Humans; Anosmia; Frailty
PubMed: 37202677
DOI: 10.1007/s15006-023-2669-6 -
Brain and Behavior Mar 2021Olfactory and taste disorders were reported in up to 30%-80% of COVID-19 patients. The purpose of our study was to objectively assess smell impairment in COVID-19...
BACKGROUND
Olfactory and taste disorders were reported in up to 30%-80% of COVID-19 patients. The purpose of our study was to objectively assess smell impairment in COVID-19 patients and to correlate olfactory function with viral recovery.
METHODS
Between 15 and 30 April 2020, hospitalized patients with confirmed SARS-CoV-2 infection underwent an objective assessment of olfactory function with the Smell Identification subtest of the Sniffin' Sticks Test (SI-SST). Association between viral recovery and SI-SST performance was evaluated.
RESULTS
51 patients were enrolled (49% males, mean age 66.2 ± 14.6 years). At the time of test administration, 45% were clinically recovered and 39% were virus-free. Objective hyposmia/anosmia was found in 45% of the patients. Subjective olfactory disorders showed no association with the clinical or viral recovery status of the patients. On the contrary, none of the patients with anosmia and the 5% of hyposmic patients at test had viral recovery. The relative risk for hyposmic patients to be still positive at swab test was 10.323 (95% CI 1.483-71.869, p < .0001). Logistic regression analysis showed an independent and significant correlation between viral clearance and SI-SST scores (OR = 2.242; 95% CI 1.322-3.802, p < .003). ROC curve analysis confirmed that a SI-SST > 10.5 predicts viral clearance with 79% sensitivity and 87% specificity (AUC = 0.883).
CONCLUSION
Hyposmia is part of COVID-19 symptoms; however, only objectively assessed olfactory function is associated with viral recovery. SI-SST is an easy and safe instrument, and further large multicentric studies should assess its value to predict infection and recovery.
Topics: Adult; Aged; Aged, 80 and over; Anosmia; COVID-19; Female; Humans; Male; Middle Aged; Olfaction Disorders; SARS-CoV-2; Smell
PubMed: 33465295
DOI: 10.1002/brb3.2006