Letter to the Editor about the Beltrán-Corbellini et al. publication: 'Acute-onset smell and taste disorders in the context of Covid-19: a pilot multicenter PCR-based case-control study' (Eur J Neurol 2020. doi: 10.1111/ene.14273)

Cerebrospinal fluid metabolomic and proteomic characterization of neurologic post-acute sequelae of SARS-CoV-2 infection

The mechanism by which SARS-CoV-2 causes neurological post-acute sequelae of SARS-CoV-2 (neuro-PASC) remains unclear. Herein, we conducted proteomic and metabolomic analyses of cerebrospinal fluid (CSF) samples from 21 neuro-PASC patients, 45 healthy volunteers, and 26 inflammatory neurological diseases patients. Our data showed 69 differentially expressed metabolites and six differentially expressed proteins between neuro-PASC patients and healthy individuals. Elevated sphinganine and ST1A1, sphingolipid metabolism disorder, and attenuated inflammatory responses may contribute to the occurrence of neuro-PASC, whereas decreased levels of 7,8-dihydropterin and activation of steroid hormone biosynthesis may play a role in the repair process. Additionally, a biomarker cohort consisting of sphinganine, 7,8-dihydroneopterin, and ST1A1 was preliminarily demonstrated to have high value in diagnosing neuro-PASC. In summary, our study represents the first attempt to integrate the diagnostic benefits of CSF with the methodological advantages of multi-omics, thereby offering valuable insights into the pathogenesis of neuro-PASC and facilitating the work of neuroscientists in disclosing different neurological dimensions associated with COVID-19.

Alterations of Urinary Microbial Metabolites and Immune Indexes Linked With COVID-19 Infection and Prognosis

Coronavirus disease 2019 (COVID-19) has evolved into an established global pandemic. Metabolomic studies in COVID-19 patients is worth exploring for further available screening methods. In our study, we recruited a study cohort of 350 subjects comprising 248 COVID-19 patients (161 non-severe cases, 60 asymptomatic cases, and 27 severe cases) and 102 healthy controls (HCs), and herein present data with respect to their demographic features, urinary metabolome, immunological indices, and follow-up health status. We found that COVID-19 resulted in alterations of 39 urinary, mainly microbial, metabolites. Using random forest analysis, a simplified marker panel including three microbial metabolites (oxoglutaric acid, indoxyl, and phenylacetamide) was constructed (AUC=0.963, 95% CI, 0.930-0.983), which exhibited higher diagnostic performance than immune feature-based panels between COVID-19 and HC groups (P<0.0001). Meanwhile, we observed that urine metabolic markers enabled discriminating asymptomatic patients (ASY) from HCs (AUC = 0.981, 95% CI, 0.946-0.996), and predicting the incidence of high-risk sequalae in COVID-19 individuals (AUC=0.931, 95% CI, 0.877-0.966). Co-expression network analysis showed that 13 urinary microbial metabolites (e.g., oxoglutaric acid) were significantly correlated with alterations of CD4⁺, CD3⁺, and CD8⁺ T-cells, as well as IFN-γ, IL-2 and IL-4 levels, suggesting close interactions between microbial metabolites and host immune dysregulation in COVID-19. Taken together, our findings indicate that urinary metabolites may have promising potential for screening of COVID-19 in different application scenarios, and provide a new entry point to understand the microbial metabolites and related immune dysfunction in COVID-19.

Zinc deficiency as a possible risk factor for increased susceptibility and severe progression of Corona Virus Disease 19

The importance of Zn for human health becomes obvious during Zn deficiency. Even mild insufficiencies of Zn cause alterations in haematopoiesis and immune functions, resulting in a proinflammatory phenotype and a disturbed redox metabolism. Although immune system malfunction has the most obvious effect, the functions of several tissue cell types are disturbed if Zn supply is limiting. Adhesion molecules and tight junction proteins decrease, while cell death increases, generating barrier dysfunction and possibly organ failure. Taken together, Zn deficiency both weakens the resistance of the human body towards pathogens and at the same time increases the danger of an overactive immune response that may cause tissue damage. The case numbers of Corona Virus Disease 19 (COVID-19) are still increasing, which is causing enormous problems for health systems and economies. There is an urgent need to reduce both the number of severe cases and the resulting deaths. While therapeutic options are still under investigation, and first vaccines have been approved, cost-effective ways to reduce the likelihood of or even prevent infection, and the transition from mild symptoms to more serious detrimental disease, are highly desirable. Nutritional supplementation might be an effective option to achieve these aims. In this review, we discuss known Zn deficiency effects in the context of an infection with Severe Acute Respiratory Syndrome-Coronavirus-2 and its currently known pathogenic mechanisms and elaborate on how severe pre-existing Zn deficiency may pre-dispose patients to a severe progression of COVID-19. First published clinical data on the association of Zn homoeostasis with COVID-19 and registered studies in progress are listed.

Evidence of Coronavirus (CoV) Pathogenesis and Emerging Pathogen SARS-CoV-2 in the Nervous System: A Review on Neurological Impairments and Manifestations

The coronavirus disease 2019 (COVID-19) pandemic is an issue of global significance that has taken the lives of many across the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for its pathogenesis. The pulmonary manifestations of COVID-19 have been well described in the literature. Initially, it was thought to be limited to the respiratory system; however, we now recognize that COVID-19 also affects several other organs, including the nervous system. Two similar human coronaviruses (CoV) that cause severe acute respiratory syndrome (SARS-CoV-1) and Middle East respiratory syndrome (MERS-CoV) are also known to cause disease in the nervous system. The neurological manifestations of SARS-CoV-2 infection are growing rapidly, as evidenced by several reports. There are several mechanisms responsible for such manifestations in the nervous system. For instance, post-infectious immune-mediated processes, direct virus infection of the central nervous system (CNS), and virus-induced hyperinflammatory and hypercoagulable states are commonly involved. Guillain-Barré syndrome (GBS) and its variants, dysfunction of taste and smell, and muscle injury are numerous examples of COVID-19 PNS (peripheral nervous system) disease. Likewise, hemorrhagic and ischemic stroke, encephalitis, meningitis, encephalopathy acute disseminated encephalomyelitis, endothelialitis, and venous sinus thrombosis are some instances of COVID-19 CNS disease. Due to multifactorial and complicated pathogenic mechanisms, COVID-19 poses a large-scale threat to the whole nervous system. A complete understanding of SARS-CoV-2 neurological impairments is still lacking, but our knowledge base is rapidly expanding. Therefore, we anticipate that this comprehensive review will provide valuable insights and facilitate the work of neuroscientists in unfolding different neurological dimensions of COVID-19 and other CoV associated abnormalities.

SARS-Cov2: a meta-analysis of symptom distribution by continent in 7310 adult COVID-19 infected patients

There is recent evidence that suggests that there are multiple strains of coronavirus in different parts of the world. Moreover, scientist have noted multiple mutations and postulated that these changes might increase the infective rate of the virus. However literature on varying severity of disease based on these strains is absent. In this meta-analysis, we have made an attempt to correlate the symptoms in different continents with respect to various studied strains of virus. We searched three databases, PubMed, EMBASE and EMCARE to identify studies reporting symptoms of COVID-19. All articles published between December 2019 and May 2020 was included in this meta-analysis. A total of 56 studies consisted of 7310 patients were included in the meta-analysis. Mean age of patients varied from 22 to 69.8 years. The pooled proportion of male patients was 52%. Highest incidence of fever (76%) and cough (56%) was noted in Chinese population. Sore throat (29%) was most common in Asian population. Upper respiratory tract symptom like Rhinorrhoea, Anosmia and dysgeusia (32%, 47% and 39%) were well documented in European population as compared to the other continents. Nausea and diarrhoea were more common in European (17%, 19%) and Australian (12%, 16%) population. Dyspnoea and fatigue were consistently similar in all the continents. We postulate that different mutations in COVID-19 virus may vary its pathogenicity and screening symptoms across all the continents should be not be generalised but continent-specific.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13337-021-00699-y.

SARS-Cov2: a meta-analysis of symptom distribution by continent in 7310 adult COVID-19 infected patients

There is recent evidence that suggests that there are multiple strains of coronavirus in different parts of the world. Moreover, scientist have noted multiple mutations and postulated that these changes might increase the infective rate of the virus. However literature on varying severity of disease based on these strains is absent. In this meta-analysis, we have made an attempt to correlate the symptoms in different continents with respect to various studied strains of virus. We searched three databases, PubMed, EMBASE and EMCARE to identify studies reporting symptoms of COVID-19. All articles published between December 2019 and May 2020 was included in this meta-analysis. A total of 56 studies consisted of 7310 patients were included in the meta-analysis. Mean age of patients varied from 22 to 69.8 years. The pooled proportion of male patients was 52%. Highest incidence of fever (76%) and cough (56%) was noted in Chinese population. Sore throat (29%) was most common in Asian population. Upper respiratory tract symptom like Rhinorrhoea, Anosmia and dysgeusia (32%, 47% and 39%) were well documented in European population as compared to the other continents. Nausea and diarrhoea were more common in European (17%, 19%) and Australian (12%, 16%) population. Dyspnoea and fatigue were consistently similar in all the continents. We postulate that different mutations in COVID-19 virus may vary its pathogenicity and screening symptoms across all the continents should be not be generalised but continent-specific.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13337-021-00699-y.

COVID-19: a new emerging respiratory disease from the neurological perspective

Coronavirus disease 2019 (COVID-19) has become a challenging public health catastrophe worldwide. The newly emerged disease spread in almost all countries and infected 100 million persons worldwide. The infection is not limited to the respiratory system but involves various body systems and may lead to multiple organ failure. Tissue degenerative changes result from direct viral invasion, indirect consequences, or through an uncontrolled immune response. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads to the brain via hematogenous and neural routes accompanied with dysfunction of the blood-brain barrier. The involvement of the central nervous system is now suspected to be among the main causes of death. The present review discusses the historical background of coronaviruses, their role in previous and ongoing pandemics, the way they escape the immune system, why they are able to spread despite all undertaken measures, in addition to the neurological manifestations, long-term consequences of the disease, and various routes of viral introduction to the CNS.

Chemosensory Dysfunction in COVID-19: Prevalences, Recovery Rates, and Clinical Associations on a Large Brazilian Sample

OBJECTIVE

Our study aimed to measure the percentage of reported olfactory or taste losses and their severity, recovery time, and association with other features in a large cohort of patients with COVID-19.

STUDY DESIGN

Prospective survey.

SETTING

Quaternary medical center and online survey.

METHODS

The perceived chemosensory capacities of 655 patients with confirmed COVID-19 were assessed with 11-point category rating scales (0, no function; 10, normal function). Patients were contacted in hospital, by phone calls, or by internet regarding their ability to smell or taste, and 143 were interviewed by phone 1 to 4 months later to assess the recovery of their chemosensory abilities.

RESULTS

The prevalence of self-reported olfactory, general taste, and taste quality-specific disturbances (sweet, sour, bitter, and salty) in the patients with COVID-19 were 82.4% (95% CI, 79.5%-85.3%), 76.2% (95% CI, 72.9%-79.4%), and 52.2% (95% CI, 48.3%-56.1%), respectively. The majority reported anosmia (42.9%). The presence of chemosensory symptoms was not associated with COVID-19 severity. At a median time >2 months after the onset of symptoms, rates of total and partial olfaction recovery were 53.8% and 44.7%, while complete or partial return to previous taste function was 68.3% and 27.6%. Less than 5% of the patients reported no chemosensory function improvement at all.

CONCLUSION

The prevalence of self-reported chemosensory dysfunction is high among patients with COVID-19. Almost all patients seem to recover a significant part of their smell and taste abilities in the first 4 months after the onset of symptoms.

Management and Prevention of Cerebrovascular Accidents in SARS-CoV-2-Positive Patients Recovering from COVID-19: a Case Report and Review of Literature

We discuss the current understanding of COVID-19’s neurological implications, their basis, and the evolving clinical consensus with a focus on cerebrovascular stroke. We further illustrate the potential significance of these implications with the aid of an accompanying case report outlining the disease course and treatment of a COVID-19 patient suffering from ischemic stroke and pulmonary embolism. The ever-growing strain on the global healthcare system due to the spread of the novel coronavirus SARS-CoV-2 requires focused attention on urgent care of independent, coexisting, and associated comorbidities, including cerebrovascular accidents. For illustration purposes, we outline the case of a 68-year-old female presenting with COVID-19 subsequently complicated by bilateral pulmonary embolism and a right-sided cerebrovascular accident. The patient was successfully managed pharmacologically and discharged without significant neurological deficit. The evidence for a hypercoagulable state in this patient along with discussion of mechanistic bases, corroborative evidence from the literature, along with relevant guidance on screening, treatment, and prophylaxis is offered. Greater study of the pathogenesis of COVID-19-related cerebrovascular complications and revisiting current guidelines on their management including potentially heightened levels of thromboprophylaxis are warranted.

Incidence, Clinical Characteristics, and Evolution of SARS-CoV-2 Infection in Patients With Inflammatory Bowel Disease: A Single-Center Study in Madrid, Spain

BACKGROUND

There are scarce data about SARS-CoV-2 infection in patients with inflammatory bowel disease (IBD). Our aim was to analyze the incidence, clinical presentation, and severity of SARS-CoV-2 infection in patients with IBD.

METHODS

This is a cross-sectional, observational study. We contacted all the patients being treated at our IBD unit to identify those patients with suspected or confirmed SARS-CoV-2 infection, following the World Health Organization case definition. Data were obtained by patient electronical medical records and by phone interview.

RESULTS

Eighty-two of 805 patients with IBD (10.2%; 95% confidence interval [CI], 8.3-12.5) were diagnosed as having confirmed (28 patients, 3.5%; 95% CI, 2.4-5.0) or suspected (54 patients, 6.7%) infection. Patient age was 46 ± 14 years, 44 patients were female (53.7%), 17.3% were smokers, 51.2% had Crohn disease (CD), and 39.0% had comorbidities. Digestive symptoms were reported in 41 patients (50.0%), with diarrhea as the most common (42.7%). One patient (1.2%) was diagnosed with IBD flare-up during SARS-CoV-2 infection. Twenty-two patients (26.8%) temporarily withdrew from their IBD treatment because of COVID-19. Most of the patients had mild disease (79.3%), and 1 patient died (1.2%). In the multivariate analysis, the presence of dyspnea was associated with moderate to severe infection (odds ratio, 5.3; 95% CI, 1.6-17.7; P = 0.01) and myalgias (odds ratio, 4.8; 95% CI, 1.3-17.9; P = 0.02) were related to a milder clinical course. Immunosuppression was not related to severity.

CONCLUSIONS

SARS-CoV-2 infection in patients with IBD is not rare. Dyspnea is associated with a more severe infection. Therapy for IBD, including immunomodulators and biologic therapy, is not related to a greater severity of COVID-19, and SARS-CoV-2 infections do not appear to be related to IBD flare-ups.

Hyposmia and Dysgeusia in COVID-19: Indication to Swab Test and Clue of CNS Involvement

Objective

To evaluate the prevalence of hyposmia and dysgeusia in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and their temporal relationship with the onset of other symptoms.

Methods

We performed a retrospective analysis of patients admitted during the month of March 2020 to the nonintensive COVID unit of Udine University Hospital on the basis of a positive swab test and/or of clinical-radiologic signs of SARS-CoV-2 infection. Patients were interviewed with a standardized questionnaire. Clinical and laboratory data were collected. Data were analyzed with descriptive statistics, and results expressed as point estimates and 95% confidence intervals (CIs).

Results

Of 141 patients admitted, 93 were interviewed. Hyposmia and dysgeusia were present in 58 cases (62.4%). In 22.4% of them, olfactory and gustatory impairment clearly preceded systemic symptoms. The presence of active smoking was very limited in both groups: 8.6% in hyposmic vs 2.9% in normosmic patients (odds ratio 3.2; 95% CI 0.3-28.6). Moreover, total leukocytes and neutrophils count were respectively 23% (effect estimate 1.23; 95% CI 1.06-1.42) and 29% (effect estimate 1.29; 95% CI 1.07-1.54) lower in the hyposmic cohort. No difference was found for other inflammatory biomarkers.

Conclusions

Hyposmia and dysgeusia are common in SARS-CoV-2 infection and can precede systemic symptoms. They should be actively searched and prompt close monitoring and isolation until infection is confirmed or disproven. The lower number of total leukocytes and neutrophils in hyposmic patients might indicate an early-phase virus-induced cytopenia.

Smell and Taste in Severe CoViD-19: Self-Reported vs. Testing

One of the most striking reported symptoms in CoViD-19 is loss of smell and taste. The frequency of these impairments and their specificity as a potential central nervous system function biomarker are of great interest as a diagnostic clue for CoViD-19 infection as opposed to other similar symptomatologic diseases and because of their implication in viral pathogenesis. Here severe CoViD-19 was investigated by comparing self-report vs. testing of smell and taste, thus the objective severity of olfactory impairment and their possible correlation with other symptoms. Because a significant discrepancy between smell and taste testing vs. self-report results (p < 0.001) emerges in our result, we performed a statistical analysis highlighting disagreement among normosmia (p < 0.05), hyposmia, severe hyposmia, and anosmia (p < 0.001) and, in hypogeusia and severe hypogeusia, while no differences are observed in normogeusia and ageusia. Therefore, we analyzed the olfactory threshold by an objective test revealing the distribution of hyposmic (34%), severe hyposmic (48%), and anosmic (13%) patients in severe CoViD-19. In severe CoViD-19 patients, taste is lost in 4.3% of normosmic individuals, 31.9% of hyposmic individuals, 46.8% of severe hyposmic individuals, and 17% of anosmic individuals. Moreover, 95% of 100 CoViD-19 patients objectively tested were affected by smell dysfunction, while 47% were affected by taste dysfunction. Furthermore, analysis by objective testing also highlighted that the severity of smell dysfunction in CoViD-19 subjects did not correlate with age and sex. In conclusion, we report by objective testing that the majority of CoViD-19 patients report severe anosmia, that most of the subjects have olfactory impairment rather than taste impairment, and, finally, that the olfactory impairment correlate with symptom onset and hospitalization (p < 0.05). Patients who exhibit severe olfactory impairment had been hospitalized for about a week from symptom onset; double time has taken place in subjects with normosmia. Our results may be limited by the relatively small number of study participants, but these suggest by objective testing that hyposmia, severe hyposmia, and anosmia may relate directly to infection severity and neurological damage. The smell test assessment could be a potential screening symptom that might contribute to the decision to test suspected cases or guide quarantine instructions, further therapeutic approach, and evaluation of neurological damage.

Neurological Complications and Noninvasive Multimodal Neuromonitoring in Critically Ill Mechanically Ventilated COVID-19 Patients

Purpose: The incidence and the clinical presentation of neurological manifestations of coronavirus disease-2019 (COVID-19) remain unclear. No data regarding the use of neuromonitoring tools in this group of patients are available. Methods: This is a retrospective study of prospectively collected data. The primary aim was to assess the incidence and the type of neurological complications in critically ill COVID-19 patients and their effect on survival as well as on hospital and intensive care unit (ICU) length of stay. The secondary aim was to describe cerebral hemodynamic changes detected by noninvasive neuromonitoring modalities such as transcranial Doppler, optic nerve sheath diameter (ONSD), and automated pupillometry. Results: Ninety-four patients with COVID-19 admitted to an ICU from February 28 to June 30, 2020, were included in this study. Fifty-three patients underwent noninvasive neuromonitoring. Neurological complications were detected in 50% of patients, with delirium as the most common manifestation. Patients with neurological complications, compared to those without, had longer hospital (36.8 ± 25.1 vs. 19.4 ± 16.9 days, p < 0.001) and ICU (31.5 ± 22.6 vs. 11.5±10.1 days, p < 0.001) stay. The duration of mechanical ventilation was independently associated with the risk of developing neurological complications (odds ratio 1.100, 95% CI 1.046-1.175, p = 0.001). Patients with increased intracranial pressure measured by ONSD (19% of the overall population) had longer ICU stay. Conclusions: Neurological complications are common in critically ill patients with COVID-19 receiving invasive mechanical ventilation and are associated with prolonged ICU length of stay. Multimodal noninvasive neuromonitoring systems are useful tools for the early detection of variations in cerebrovascular parameters in COVID-19.

Headache: A striking prodromal and persistent symptom, predictive of COVID-19 clinical evolution

OBJECTIVE

To define headache characteristics and evolution in relation to COVID-19 and its inflammatory response.

METHODS

This is a prospective study, comparing clinical data and inflammatory biomarkers of COVID-19 patients with and without headache, recruited at the Emergency Room. We compared baseline with 6-week follow-up to evaluate disease evolution.

RESULTS

Of 130 patients, 74.6% (97/130) had headache. In all, 24.7% (24/97) of patients had severe pain with migraine-like features. Patients with headache had more anosmia/ageusia (54.6% vs. 18.2%; p < 0.0001). Clinical duration of COVID-19 was shorter in the headache group (23.9 ± 11.6 vs. 31.2 ± 12.0 days; p = 0.028). In the headache group, IL-6 levels were lower at the ER (22.9 (57.5) vs. 57.0 (78.6) pg/mL; p = 0.036) and more stable during hospitalisation. After 6 weeks, of 74 followed-up patients with headache, 37.8% (28/74) had ongoing headache. Of these, 50% (14/28) had no previous headache history. Headache was the prodromal symptom of COVID-19 in 21.4% (6/28) of patients with persistent headache (p = 0.010).

CONCLUSIONS

Headache associated with COVID-19 is a frequent symptom, predictive of a shorter COVID-19 clinical course. Disabling headache can persist after COVID-19 resolution. Pathophysiologically, its migraine-like features may reflect an activation of the trigeminovascular system by inflammation or direct involvement of SARS-CoV-2, a hypothesis supported by concomitant anosmia.

Loss of smell in COVID-19 patients: a critical review with emphasis on the use of olfactory tests

Since December 2019, an outbreak of a newly isolated coronavirus (SARS-CoV-2) appeared in Wuhan, China, and then spread worldwide. Recently, it has emerged that a number of patients may present with sudden hyposmia, sometimes without other symptoms of the disease. We performed a critical review on the methods used to date to investigate the olfactory function in COVID-19 patients in order to establish which should be considered the most appropriate to use during this pandemic. Literature analysis showed that the diagnosis of hyposmia in COVID-19 patients was mainly made through subjective symptomatology collected by questionnaires and/or interview. Psychophysical tests were carried out in a few studies showing significant discrepancies between the self-reported sense of smell and test results. To date the methods used by authors to investigate smell impairment in COVID-19 patients have been very heterogeneous and predominantly based on self-reported questionnaires leading to confusing and inconclusive results. We suggest that simple validated self-administered psychophysical olfactory tests could be a valuable instrument to investigate isolated/quarantined or hospitalised COVID-19 patients referring smell impairment in order to confirm olfactory dysfunction.

Smell and taste changes are early indicators of the COVID-19 pandemic and political decision effectiveness

In response to the COVID-19 pandemic, many governments have taken drastic measures to avoid an overflow of intensive care units. Accurate metrics of disease spread are critical for the reopening strategies. Here, we show that self-reports of smell/taste changes are more closely associated with hospital overload and are earlier markers of the spread of infection of SARS-CoV-2 than current governmental indicators. We also report a decrease in self-reports of new onset smell/taste changes as early as 5 days after lockdown enforcement. Cross-country comparisons demonstrate that countries that adopted the most stringent lockdown measures had faster declines in new reports of smell/taste changes following lockdown than a country that adopted less stringent lockdown measures. We propose that an increase in the incidence of sudden smell and taste change in the general population may be used as an indicator of COVID-19 spread in the population.

Emerging Neurology of COVID-19

The virus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the current pandemic known as coronavirus disease 2019 (COVID-19) with severe respiratory illness as the predominant manifestation. Neurologic complications from COVID-19 were reported in the early stages of the pandemic and are now increasingly recognized. These include various symptoms like headache and anosmia as well as neurologic complications of severe COVID-19 like encephalopathy, seizures, and stroke. There are few reports of direct involvement of the central nervous system with SARS-CoV-2 causing meningoencephalitis. There is concern for higher incidence and severity of COVID-19 in patients with chronic neurologic conditions. Here, we review the emerging literature along with our anecdotal experience in regard to these neurologic manifestations in patients with COVID-19 and detail the putative pathophysiologic mechanisms for the same.

Neurological manifestations of coronavirus infections - a systematic review

To optimize diagnostic workup of the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, we systematically reviewed neurological and neuroradiological manifestations of SARS-CoV-2 and all other known human coronavirus species (HCoV). Which lessons can we learn? We identified relevant publications (until 26 July 2020) using systematic searches in PubMed, Web of Science, and Ovid EMBASE with predefined search strings. A total of 4571 unique publications were retrieved, out of which 378 publications were selected for in-depth analysis by two raters, including a total of 17549 (out of which were 14418 SARS-CoV-2) patients. Neurological complications and associated neuroradiological manifestations are prevalent for all HCoVs (HCoV-229E, HKU1, NL63, OC43, Middle East respiratory syndrome (MERS)-CoV, SARS-CoV-1, and SARS-CoV-2). Moreover there are similarities in symptomatology across different HCoVs, particularly between SARS-CoV-1 and SARS-CoV-2. Common neurological manifestations include fatigue, headache, and smell/taste disorders. Additionally, clinicians need to be attentive for at least five classes of neurological complications: (1) Cerebrovascular disorders including ischemic stroke and macro/micro-hemorrhages, (2) encephalopathies, (3) para-/postinfectious immune-mediated complications such as Guillain-Barré syndrome and acute disseminated encephalomyelitis, (4) (meningo-)encephalitis, potentially with concomitant seizures, and (5) neuropsychiatric complications such as psychosis and mood disorders. Our systematic review highlights the need for vigilance regarding neurological complications in patients infected by SARS-CoV-2 and other HCoVs, especially since some complications may result in chronic disability. Neuroimaging protocols should be designed to specifically screen for these complications. Therefore, we propose practical imaging guidelines to facilitate the diagnostic workup and monitoring of patients infected with HCoVs.

Neuropsychiatric aspects of COVID-19 pandemic: A selective review

Corona virus disease (COVID-19) has been declared as a controllable pandemic by the World Health Organization (WHO). COVID-19 though is a predominantly respiratory illness; it can also affect brain and other organs like kidneys, heart and liver. Neuropsychiatric manifestations are common during viral pandemics but are not effectively addressed. Fever and cough are common symptoms only in infected individuals but headache and sleep disturbances are common even in uninfected general public. In this selective review, the authors report the available evidence of neuropsychiatric morbidity during the current COVID-19 crisis. The authors also discuss the postulated neuronal mechanisms of the corona virus infection sequelae.

Gustatory Dysfunction: A Highly Specific and Smell-Independent Symptom of COVID-19

Chemosensitive dysfunctions are now considered as frequent and early symptoms of coronavirus disease 2019 (COVID-19). In the last few weeks, researchers' greatest efforts have been focusing mainly on the analysis of olfactory disorders, neglecting taste dysfunctions. According to our psychophysical evaluations, it can be inferred that the pathogenesis of taste disorders in COVID-19 patients is largely smell-independent. Moreover, isolated gustatory disorders are highly specific of SARS-CoV-2 infection. For these reasons, it is essential that gustatory dysfunctions, like olfactory disorders, are included in the COVID-19 guidelines.

COVID-19 and anosmia: A review based on up-to-date knowledge

The pandemic of Coronavirus Disease 2019 (COVID-19) has caused a vast disaster throughout the world. There is increasing evidence that olfactory dysfunction can present in COVID-19 patients. Anosmia can occur alone or can be accompanied by other symptoms of COVID-19, such as a dry cough. However, the pathogenic mechanism of olfactory dysfunction and its clinical characteristics in patients with COVID-19 remains unclear. Multiple cross-sectional studies have demonstrated that the incidence rate of olfactory dysfunction in COVID-19 patients varies from 33.9–68% with female dominance. Anosmia and dysgeusia are often comorbid in COVID-19 patients. Otolaryngologists should be mindful of the symptom of anosmia in outpatients so as not to delay the diagnosis of COVID-19. In this paper, we have reviewed the relevant knowledge based on up-to-date literature.

Neurologic manifestations in hospitalized patients with COVID-19: The ALBACOVID registry

OBJECTIVE

The coronavirus disease 2019 (COVID-19) has spread worldwide since December 2019. Neurologic symptoms have been reported as part of the clinical spectrum of the disease. We aimed to determine whether neurologic manifestations are common in hospitalized patients with COVID-19 and to describe their main characteristics.

METHODS

We systematically reviewed all patients diagnosed with COVID-19 admitted to the hospital in a Spanish population during March 2020. Demographic characteristics, systemic and neurologic clinical manifestations, and complementary tests were analyzed.

RESULTS

Of 841 patients hospitalized with COVID-19 (mean age 66.4 years, 56.2% men), 57.4% developed some form of neurologic symptom. Nonspecific symptoms such as myalgias (17.2%), headache (14.1%), and dizziness (6.1%) were present mostly in the early stages of infection. Anosmia (4.9%) and dysgeusia (6.2%) tended to occur early (60% as the first clinical manifestation) and were more frequent in less severe cases. Disorders of consciousness occurred commonly (19.6%), mostly in older patients and in severe and advanced COVID-19 stages. Myopathy (3.1%), dysautonomia (2.5%), cerebrovascular diseases (1.7%), seizures (0.7%), movement disorders (0.7%), encephalitis (n = 1), Guillain-Barré syndrome (n = 1), and optic neuritis (n = 1) were also reported, but less frequent. Neurologic complications were the main cause of death in 4.1% of all deceased study participants.

CONCLUSIONS

Neurologic manifestations are common in hospitalized patients with COVID-19. In our series, more than half of patients presented some form of neurologic symptom. Clinicians need to maintain close neurologic surveillance for prompt recognition of these complications. The mechanisms and consequences of severe acute respiratory syndrome coronavirus type 2 neurologic involvement require further studies.

One-Seventh of Patients with COVID-19 Had Olfactory and Gustatory Abnormalities as Their Initial Symptoms: A Systematic Review and Meta-Analysis

Coronavirus disease 2019 (COVID-19) patients exhibited protean clinical manifestations. Olfactory and gustatory abnormalities (anosmia and ageusia) were observed in COVID-19 patients, but the reported prevalence varied. In this systematic review, the prevalence of olfactory and gustatory abnormalities (OGA) was evaluated in laboratory-confirmed COVID-19 patients. On 8 May 2020, 14,506 articles were screened, while 12 of them were enrolled. A total of 1739 COVID-19 patients were analyzed, with a wide range of prevalence observed (5.6-94%). The pooled prevalence was 48.5% with high heterogeneity (I², 98.8%; p < 0.0001). In total, 15.5% had OGA as their first symptom (I², 22.6%; p = 0.27) among the patients analyzed. Contradictory to COVID-19 negative controls, patients with COVID-19 had a higher risk of OGA (odds ratio, 5.3; I², 66.5%; p = 0.03). In conclusion, approximately half of COVID-19 patients had OGA, and one-seventh of them had OGA as their initial symptoms. OGA were cardinal symptoms of COVID-19, which may serve as clues for early diagnosis. Diagnostic testing for SARS-CoV-2 was suggested in patients with OGA during the COVID-19 pandemic to ensure timely diagnosis and appropriate quarantine.

Neurological Manifestations of Severe SARS-CoV-2 Infection: Potential Mechanisms and Implications of Individualized Mechanical Ventilation Settings

In December 2019, an outbreak of illness caused by a novel coronavirus (2019-nCoV, subsequently renamed SARS-CoV-2) was reported in Wuhan, China. Coronavirus disease 2019 (COVID-19) quickly spread worldwide to become a pandemic. Typical manifestations of COVID-19 include fever, dry cough, fatigue, and respiratory distress. In addition, both the central and peripheral nervous system can be affected by SARS-CoV-2 infection. These neurological changes may be caused by viral neurotropism, by a hyperinflammatory and hypercoagulative state, or even by mechanical ventilation-associated impairment. Hypoxia, endothelial cell damage, and the different impacts of different ventilatory strategies may all lead to increased stress and strain, potentially exacerbating the inflammatory response and leading to a complex interaction between the lungs and the brain. To date, no studies have taken into consideration the possible secondary effect of mechanical ventilation on brain recovery and outcomes. The aim of our review is to provide an updated overview of the potential pathogenic mechanisms of neurological manifestations in COVID-19, discuss the physiological issues related to brain-lung interactions, and propose strategies for optimization of respiratory support in critically ill patients with SARS-CoV-2 pneumonia.

Review of practical recommendations for otolaryngologists and head and neck surgeons during the COVID-19 pandemic

INTRODUCTION

Otolaryngologists are at very high risk of COVID-19 infection while performing examination or surgery. Strict guidelines for these specialists have not already been provided, while currently available recommendations could presumably change in course of COVID-19 pandemic as the new data increases.

OBJECTIVES

This study aimed to synthesize evidence concerning otolaryngology during COVID-19 pandemic. It presents a review of currently existing guidelines and recommendations concerning otolaryngological procedures and surgeries during COVID-19 pandemic, and provides a collective summary of all crucial information for otolaryngologists. It summarizes data concerning COVID-19 transmission, diagnosis, and clinical presentation highlighting the information significant for otolaryngologists.

METHODS

The Medline and Web of Science databases were searched without time limit using terms ''COVID-19", "SARS-CoV-2" in conjunction with "head and neck surgery", "otorhinolaryngological manifestations".

RESULTS

Patients in stable condition should be consulted using telemedicine options. Only emergency consultations and procedures should be performed during COVID-19 pandemic. Mucosa-involving otolaryngologic procedures are considered high risk procedures and should be performed using enhanced PPE (N95 respirator and full face shield or powered air-purifying respirator, disposable gloves, surgical cap, gown, shoe covers). Urgent surgeries for which there is not enough time for SARS-CoV-2 screening are also considered high risk procedures. These operations should be performed in a negative pressure operating room with high-efficiency particulate air filtration. Less urgent cases should be tested for COVID-19 twice, 48 h preoperatively in 24 h interval.

CONCLUSIONS

This review serves as a collection of current recommendations for otolaryngologists for how to deal with their patients during COVID-19 pandemic.

The diagnostic value of detecting sudden smell loss among asymptomatic COVID-19 patients in early stage: The possible early sign of COVID-19

IMPORTANCE

The newly emerged coronavirus disease 19 (COVID-19), is threatening the world. Olfactory or gustatory dysfunction is reported as one of the symptoms worldwide. As reported so far, different clinical features have been reported according to outbreak sites and gender; most of the patients, who complained of anosmia or hyposmia, were Europeans. We had a fast review for novel articles about COVID-19 infection and olfactory function.

OBSERVATIONS

Rapid reviews for COVID-19 or other viral infection and olfactory and/or gustatory dysfunctions were done in this review. Up to date, a lot of reports have shown that olfactory dysfunction is related to viral infections but no exact mechanism, clinical course, and definite treatment have been discovered, which is also same in COVID-19. In general, intranasal steroid (INS) and oral steroid for short time help improve the recovery of the olfactory function in case of olfactory dysfunction after virus infection. Considering severe respiratory complications and immunocompromised state of COVID-19, the use of steroid should be limited and cautious because we do not have enough data to support the usage of steroid to treat olfactory dysfunction in the clinical course of COVID-19.

CONCLUSIONS AND RELEVANCE

In the days of pandemic COVID-19, we should keep in mind that olfactory dysfunctions, even without other upper respiratory infection or otolaryngologic symptoms, might be the early signs of COVID-19.

Coronaviruses and the central nervous system

Seven coronavirus (CoV) species are known human pathogens: the epidemic viruses SARS-CoV, SARS-CoV-2, and MERS-CoV and those continuously circulating in human populations since initial isolation: HCoV-OC43, HCoV-229E, HCoV-HKU1, and HCoV-NL63. All have associations with human central nervous system (CNS) dysfunction. In infants and young children, the most common CNS phenomena are febrile seizures; in adults, non-focal abnormalities that may be either neurologic or constitutional. Neurotropism and neurovirulence are dependent in part on CNS expression of cell surface receptors mediating viral entry, and host immune response. In adults, CNS receptors for epidemic viruses are largely expressed on brain vasculature, whereas receptors for less pathogenic viruses are present in vasculature, brain parenchyma, and olfactory neuroepithelium, dependent upon viral species. Human coronaviruses can infect circulating mononuclear cells, but meningoencephalitis is rare. Well-documented human neuropathologies are infrequent and, for SARS, MERS, and COVID-19, can entail cerebrovascular accidents originating extrinsically to brain. There is evidence of neuronal infection in the absence of inflammatory infiltrates with SARS-CoV, and CSF studies of rare patients with seizures have demonstrated virus but no pleocytosis. In contrast to human disease, animal models of neuropathogenesis are well developed, and pathologies including demyelination, neuronal necrosis, and meningoencephalitis are seen with both native CoVs as well as human CoVs inoculated into nasal cavities or brain. This review covers basic CoV biology pertinent to CNS disease; the spectrum of clinical abnormalities encountered in infants, children, and adults; and the evidence for CoV infection of human brain, with reference to pertinent animal models of neuropathogenesis.

Dizziness can be an early sole clinical manifestation for COVID-19 infection: A case report

SARS‐CoV‐2 is a novel strain of coronavirus that was first identified in Wuhan, China; it has since spread rapidly throughout the world. Most of the patients with COVID‐19 present with respiratory symptoms, including cough, nasal symptoms, fever, and shortness of breath. However, several groups have reported that SARS‐CoV‐2 can infect the central nervous system via the olfactory bulb followed by spread throughout the brain and peripheral nervous system. This brief report illustrated a 78‐year‐old man who presented to the emergency department (ED) on March 22, 2020, with chief complaints of dizziness and unsteadiness while walking. He had no symptoms suggestive of COVID‐19 on arrival. SARS‐CoV‐2 nasopharyngeal swab test performed at that time due to his atypical presentation and lymphocytopenia was positive for virus nucleic acids. The neurological symptoms associated with COVID‐19 are frequently non‐specific and may emerge several days before the respiratory symptoms; as such, identification of patients presenting with these subtle and seemingly unremarkable COVID‐19 symptoms will be quite difficult. Added to this, numerous countries still limit testing for SARS‐COV‐2 to patients presenting with fever or respiratory symptoms. Frontline physicians should be aware of early, non‐specific symptoms associated with SARS‐CoV‐2 infection.

Neurological Manifestations of COVID-19: A systematic review and current update

The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), was first identified in December of 2019 in the city of Wuhan, China. Since the outbreak, various reports detail its symptoms and outcomes, primarily focusing on respiratory complications. However, reports are emerging of the virus’ effects systemically, including that of the nervous system. A review of all current published literature was conducted, and we report that headache and anosmia were common neurological manifestations of SARS‐CoV‐2. Less common symptoms include seizure, stroke and isolated cases of Guillain‐Barre syndrome. Further research is now warranted to precisely determine the relationship between those patients developing neurological sequelae, their clinical state and any subsequent morbidity and mortality.

Neurosensory dysfunction: A diagnostic marker of early COVID-19

OBJECTIVE

To describe neurosensory dysfunctions, including hyposmia, hypogeusia, and tinnitus, in patients with COVID-19.

METHODS

Clinical characteristics and oropharyngeal swabs were obtained from 86 patients with COVID-19 hospitalized in Guangzhou Eighth People's Hospital. The chronological analysis method was used to detail neurosensory dysfunction. The cycle threshold (Ct) values were used to approximately indicate viral load.

RESULTS

Forty-four (51.2%) patients had neurosensory dysfunction: hyposmia (34, 39.5%), hypogeusia (33, 38.4%), and tinnitus (three, 3.5%). Neurosensory dysfunction was significantly more common in patients under 40 years old (p = 0.001) and women (p = 0.006). Hyposmia and hypogeusia coexisted in 23 (26.7%) patients. The interval between onset of hyposmia and hypogeusia was 0.7 ± 1.46 days. The interval from onset of hyposmia and hypogeusia to typical COVID-19 symptoms was 0.22 ± 4.57 and 0.75 ± 6.77 days; the interval from onset of hyposmia and hypogeusia to admission was 6.06 ± 6.68 and 5.76 ± 7.68 days; and the duration of hyposmia and hypogeusia was 9.09 ± 5.74 and 7.12 ± 4.66 days, respectively. The viral load was high following symptoms onset, peaked within the first week, and gradually declined.

CONCLUSIONS

Neurosensory dysfunction tends to occur in the early stage of COVID-19, and it could be used as a marker for the early diagnosis of COVID-19.

[Smell disorders at COVID-19 - the current level of knowledge]

Nachdem anfängliche Berichte über die SARS-CoV-2-Infektion Riech- und Schmeckstörungen kaum erwähnten, haben mittlerweile mehrere Studien, insbesondere aus Europa und den USA, diese Symptome als Merkmal von COVID-19 bestätigt. Gut 2 Drittel der Erkrankten scheinen im Verlauf der Erkrankung eine Riech- und Schmeckminderung zu erleiden, wobei die meisten der bislang veröffentlichten Studien auf Fragebögen und anamnestischen Daten basieren. Validierte Riechtests wurden bislang nur in wenigen Studien eingesetzt. Eine Unterscheidung zwischen Schmeck- und Geschmacksstörungen, also eine Abgrenzung des retronasalen Aromaschmeckens über das olfaktorische System von der Dysfunktion von Geschmackspapillen und der weiterführenden Hirnnerven, erfolgte in den bisher verfügbaren Studien zumeist nicht. Einige Berichte assoziieren die Riechstörungen mit einem milderen klinischen Krankheitsverlauf. Gleichzeitig stellt das Riechsystem über den Bulbus olfactorius eine Eintrittspforte in das zentrale Nervensystem dar, und eine Riechstörung könnte ein prädisponierender Faktor für zentral-neurologische Symptome sein. Die klinische Bedeutung von Riech- und Schmeckstörungen bei COVID-19-Patienten ist aktuell noch unklar. Weitere offene Fragen betreffen die genaue Prävalenz und die Prognose, sodass insgesamt höherwertige Studien mit validierten Riechtests und größeren Patientenzahlen zu fordern sind.

The influenza virus, SARS-CoV-2, and the airways: Clarification for the otorhinolaryngologist

The influenza virus and SARS-CoV-2 cause trivial upper and severe lower respiratory infections (Influenza virus 290,000 to 650,000 deaths/year). These viruses come into contact with the airways either by direct projection, by secondary inhalation of airborne droplets, or by handling (fomites). The objective of this article is to clarify the mechanisms of production and penetration of droplets of secretions emitted during all expiratory phenomena likely to transport these viruses and come into contact with the respiratory mucosa. The droplets>5μm follow the laws of ballistics, those<5μm follow Brownian motion and remain suspended in the air. The aerosols of droplets are very heterogeneous whether the subject is healthy or sick. During an infectious period, not all droplets contain viral RNA. If these RNAs are detectable around patients, on surfaces, and in the ambient air at variable distances according to the studies (from 0.5m to beyond the patient's room), this is without prejudice to the infectious nature (viability) of the virus and the minimum infectious dose. There is a time lag between the patient's infectious period and that of RNA detection for both viruses. Subsequently, the inhaled particles must meet the laws of fluid dynamics (filtration) to settle in the respiratory tree. All of this partly explains the contagiousness and the clinical expression of these two viruses from the olfactory cleft to the alveoli.

Anosmia and dysgeusia associated with SARS-CoV-2 infection: an age-matched case-control study

BACKGROUND

Anosmia and dysgeusia have been reported as potential symptoms of coronavirus disease 2019. This study aimed to confirm whether anosmia and dysgeusia are specific symptoms among those who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

We conducted an age-matched case-control study in the Eastern Townships region of Quebec between Mar. 10 and Mar. 23, 2020. We included adults (age ≥ 18 yr) who tested positive for SARS-CoV-2 by reverse transcription polymerase chain reaction. Cases were matched (1:1) according to 5-year age groups with control patents selected randomly from among all patients who tested negative for SARS-CoV-2 during the same period. Demographic and laboratory information was collected from medical records. Clinical symptoms and comorbidities associated with anosmia and dysgeusia were obtained by telephone interview with a standardized questionnaire.

RESULTS

Among 2883 people tested for SARS-CoV-2, we identified 134 positive cases (70 women [52.2%] and 64 men [47.8%]; median age 57.1 [interquartile range 41.2-64.5] yr). The symptoms independently associated with SARS-CoV-2 positivity in conditional logistic regression were anosmia or dysgeusia or both (adjusted odds ratio [OR] 62.9, 95% confidence interval [CI] 11.0-359.7), presence of myalgia (adjusted OR 7.6, 95% CI 1.9-29.9), blurred vision (adjusted OR 0.1, 95% CI 0.0-0.8) and chest pain (adjusted OR 0.1, 95% CI 0.0-0.6).

INTERPRETATION

We found a strong association between olfactory and gustatory symptoms and SARS-CoV-2 positivity. These symptoms should be considered as common and distinctive features of SARS-CoV-2 infection and should serve as an indication for testing and possible retesting of people whose first test result is negative.