Should we expect neurological symptoms in the SARS-CoV-2 epidemic?

Links between COVID-19 and Parkinson's disease/Alzheimer's disease: reciprocal impacts, medical care strategies and underlying mechanisms

The impact of coronavirus disease 2019 (COVID-19) pandemic on patients with neurodegenerative diseases and the specific neurological manifestations of COVID-19 have aroused great interest. However, there are still many issues of concern to be clarified. Therefore, we review the current literature on the complex relationship between COVID-19 and neurodegenerative diseases with an emphasis on Parkinson's disease (PD) and Alzheimer's disease (AD). We summarize the impact of COVID-19 infection on symptom severity, disease progression, and mortality rate of PD and AD, and discuss whether COVID-19 infection could trigger PD and AD. In addition, the susceptibility to and the prognosis of COVID-19 in PD patients and AD patients are also included. In order to achieve better management of PD and AD patients, modifications of care strategies, specific drug therapies, and vaccines during the pandemic are also listed. At last, mechanisms underlying the link of COVID-19 with PD and AD are reviewed.

Lactoferrin for Mental Health: Neuro-Redox Regulation and Neuroprotective Effects across the Blood-Brain Barrier with Special Reference to Neuro-COVID-19

Overall mental health depends in part on the blood-brain barrier, which regulates nutrient transfer in-and-out of the brain and its central nervous system. Lactoferrin, an innate metal-transport protein, synthesized in the substantia nigra, particularly in dopaminergic neurons and activated microglia is vital for brain physiology. Lactoferrin rapidly crosses the blood-brain barrier via receptor-mediated transcytosis and accumulates in the brain capillary endothelial cells. Lactoferrin receptors are additionally present on glioma cells, brain micro-vessels, and neurons. As a regulator of neuro-redox, microglial lactoferrin is critical for protection/repair of neurons and healthy brain function. Iron imbalance and oxidative stress are common among patients with neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease, dementia, depression, and multiple sclerosis. As an endogenous iron-chelator, lactoferrin prevents iron accumulation and dopamine depletion in Parkinson's disease patients. Oral lactoferrin supplementation could modulate the p-Akt/PTEN pathway, reduce Aβ deposition, and ameliorate cognitive decline in Alzheimer's disease. Novel lactoferrin-based nano-therapeutics have emerged as effective drug-delivery systems for clinical management of neurodegenerative disorders. Recent emergence of the Coronavirus disease-2019 (COVID-19) pandemic, initially considered a respiratory illness, demonstrated a broader virulence spectrum with the ability to cross the blood-brain barrier and inflict a plethora of neuropathological manifestations in the brain - the Neuro-COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are widely reported in Parkinson's disease, Alzheimer's disease, dementia, and multiple sclerosis patients with aggravated clinical outcomes. Lactoferrin, credited with several neuroprotective benefits in the brain could serve as a potential adjuvant in the clinical management of Neuro-COVID-19.

SARS-CoV-2 infection in multiple sclerosis patients: interaction with treatments, adjuvant therapies, and vaccines against COVID-19

The SARS-CoV-2 pandemic has raised particular concern for people with Multiple Sclerosis, as these people are believed to be at increased risk of infection, especially those being treated with disease-modifying therapies. Therefore, the objective of this review was to describe how COVID-19 affects people who suffer from Multiple Sclerosis, evaluating the risk they have of suffering an infection by this virus, according to the therapy to which they are subjected as well as the immune response of these patients both to infection and vaccines and the neurological consequences that the virus can have in the long term. The results regarding the increased risk of infection due to treatment are contradictory. B-cell depletion therapies may cause patients to have a lower probability of generating a detectable neutralizing antibody titer. However, more studies are needed to help understand how this virus works, paying special attention to long COVID and the neurological symptoms that it causes.

COVID-19 causes neuronal degeneration and reduces neurogenesis in human hippocampus

Recent investigations of COVID-19 have largely focused on the effects of this novel virus on the vital organs in order to efficiently assist individuals who have recovered from the disease. In the present study we used hippocampal tissue samples extracted from people who died after COVID-19. Utilizing histological techniques to analyze glial and neuronal cells we illuminated a massive degeneration of neuronal cells and changes in glial cells morphology in hippocampal samples. The results showed that in hippocampus of the studied brains there were morphological changes in pyramidal cells, an increase in apoptosis, a drop in neurogenesis, and change in spatial distribution of neurons in the pyramidal and granular layer. It was also demonstrated that COVID-19 alter the morphological characteristics and distribution of astrocyte and microglia cells. While the exact mechanism(s) by which the virus causes neuronal loss and morphology in the central nervous system (CNS) remains to be determined, it is necessary to monitor the effect of SARS-CoV-2 infection on CNS compartments like the hippocampus in future investigations. As a result of what happened in the hippocampus secondary to COVID-19, memory impairment may be a long-term neurological complication which can be a predisposing factor for neurodegenerative disorders through neuroinflammation and oxidative stress mechanisms.

Assessment of Neurocognitive Functions, Olfaction, Taste, Mental, and Psychosocial Health in COVID-19 in Adults: Recommendations for Harmonization of Research and Implications for Clinical Practice

OBJECTIVE

To propose a set of internationally harmonized procedures and methods for assessing neurocognitive functions, smell, taste, mental, and psychosocial health, and other factors in adults formally diagnosed with COVID-19 (confirmed as SARS-CoV-2 + WHO definition).

METHODS

We formed an international and cross-disciplinary NeuroCOVID Neuropsychology Taskforce in April 2020. Seven criteria were used to guide the selection of the recommendations' methods and procedures: (i) Relevance to all COVID-19 illness stages and longitudinal study design; (ii) Standard, cross-culturally valid or widely available instruments; (iii) Coverage of both direct and indirect causes of COVID-19-associated neurological and psychiatric symptoms; (iv) Control of factors specifically pertinent to COVID-19 that may affect neuropsychological performance; (v) Flexibility of administration (telehealth, computerized, remote/online, face to face); (vi) Harmonization for facilitating international research; (vii) Ease of translation to clinical practice.

RESULTS

The three proposed levels of harmonization include a screening strategy with telehealth option, a medium-size computerized assessment with an online/remote option, and a comprehensive evaluation with flexible administration. The context in which each harmonization level might be used is described. Issues of assessment timelines, guidance for home/remote assessment to support data fidelity and telehealth considerations, cross-cultural adequacy, norms, and impairment definitions are also described.

CONCLUSIONS

The proposed recommendations provide rationale and methodological guidance for neuropsychological research studies and clinical assessment in adults with COVID-19. We expect that the use of the recommendations will facilitate data harmonization and global research. Research implementing the recommendations will be crucial to determine their acceptability, usability, and validity.

Medicinal Herbs in the Relief of Neurological, Cardiovascular, and Respiratory Symptoms after COVID-19 Infection A Literature Review

COVID-19 infection causes complications, even in people who have had a mild course of the disease. The most dangerous seem to be neurological ailments: anxiety, depression, mixed anxiety–depressive (MAD) syndromes, and irreversible dementia. These conditions can negatively affect the respiratory system, circulatory system, and heart functioning. We believe that phytotherapy can be helpful in all of these conditions. Clinical trials confirm this possibility. The work presents plant materials (Valeriana officinalis, Melissa officinalis, Passiflora incarnata, Piper methysticum, Humulus lupulus, Ballota nigra, Hypericum perforatum, Rhodiola rosea, Lavandula officinalis, Paullinia cupana, Ginkgo biloba, Murraya koenigii, Crataegus monogyna and oxyacantha, Hedera helix, Polygala senega, Pelargonium sidoides, Lichen islandicus, Plantago lanceolata) and their dominant compounds (valeranon, valtrate, apigenin, citronellal, isovitexin, isoorientin, methysticin, humulone, farnesene, acteoside, hypericin, hyperforin, biapigenin, rosavidin, salidroside, linalool acetate, linalool, caffeine, ginkgolide, bilobalide, mihanimbine, epicatechin, hederacoside C,α-hederine, presegenin, umckalin, 6,7,8-trixydroxybenzopyranone disulfate, fumaroprotocetric acid, protolichesteric acid, aucubin, acteoside) responsible for their activity. It also shows the possibility of reducing post-COVID-19 neurological, respiratory, and cardiovascular complications, which can affect the functioning of the nervous system.

Melatonin and multiple sclerosis: antioxidant, anti-inflammatory and immunomodulator mechanism of action

BACKGROUND

Melatonin is an indole hormone secreted primarily by the pineal gland that showing anti-oxidant, anti-inflammatory and anti-apoptotic capacity. It can play an important role in the pathophysiological mechanisms of various diseases. In this regard, different studies have shown that there is a relationship between Melatonin and Multiple Sclerosis (MS). MS is a chronic immune-mediated disease of the Central Nervous System.

AIM

The objective of this review was to evaluate the mechanisms of action of melatonin on oxidative stress, inflammation and intestinal dysbiosis caused by MS, as well as its interaction with different hormones and factors that can influence the pathophysiology of the disease.

RESULTS

Melatonin causes a significant increase in the levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione and can counteract and inhibit the effects of the NLRP3 inflammasome, which would also be beneficial during SARS-CoV-2 infection. In addition, melatonin increases antimicrobial peptides, especially Reg3β, which could be useful in controlling the microbiota.

CONCLUSION

Melatonin could exert a beneficial effect in people suffering from MS, running as a promising candidate for the treatment of this disease. However, more research in human is needed to help understand the possible interaction between melatonin and certain sex hormones, such as estrogens, to know the potential therapeutic efficacy in both men and women.

COVID-19 and Neurodegenerative Diseases: Prion-Like Spread and Long-Term Consequences

COVID-19 emerged as a global pandemic starting from Wuhan in China and spread at a lightning speed to the rest of the world. One of the potential long-term outcomes that we speculate is the development of neurodegenerative diseases as a long-term consequence of SARS-CoV-2 especially in people that have developed severe neurological symptoms. Severe inflammatory reactions and aging are two very strong common links between neurodegenerative diseases and COVID-19. Thus, patients that have very high viral load may be at high risk of developing long-term adverse neurological consequences such as dementia. We hypothesize that people with neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and aged people are at higher risk of getting the COVID-19 than normal adults. The basis of this hypothesis is the fact that SARS-CoV-2 uses as a receptor angiotensin-converting enzyme 2 to enter the host cell and that this interaction is calcium-dependent. This could then suggest a direct relationship between neurodegenerative diseases, ACE-2 expression, and the susceptibility to COVID-19. The analysis of the available literature showed that COVID-19 virus is neurotropic and was found in the brains of patients infected with this virus. Furthermore, that the risk of having the infection increases with dementia and that infected people with severe symptoms could develop dementia as a long-term consequence. Dementia could be developed following the acceleration of the spread of prion-like proteins. In the present review we discuss current reports concerning the prevalence of COVID-19 in dementia patients, the individuals that are at high risk of suffering from dementia and the potential acceleration of prion-like proteins spread following SARS-CoV-2 infection.

Rituximab for the treatment of multiple sclerosis: a review

In the last decades, evidence suggesting the direct or indirect involvement of B cells on multiple sclerosis (MS) pathogenesis has accumulated. The increased amount of data on the efficacy and safety of B-cell-depleting therapies from several studies has suggested the addition of these drugs as treatment options to the current armamentarium of disease modifying therapies (DMTs) for MS. Particularly, rituximab (RTX), a chimeric monoclonal antibody directed at CD20 positive B lymphocytes resulting in cell-mediated apoptosis, has been demonstrated to reduce inflammatory activity, incidence of relapses and new brain lesions on magnetic resonance imaging (MRI) in patients with relapsing-remitting MS (RRMS). Additional evidence also demonstrated that patients with progressive MS (PMS) may benefit from RTX, which also showed to be well tolerated, with acceptable safety risks and favorable cost-effectiveness profile.Despite these encouraging results, RTX is currently approved for non-Hodgkin's lymphoma, chronic lymphocytic leukemia, several forms of vasculitis and rheumatoid arthritis, while it can only be administered off-label for MS treatment. Between Northern European countries exist different rules for using not licensed drug for treating MS. The Sweden MS register reports a high rate (53.5%) of off-label RTX prescriptions in relation to other annually started DMTs to treat MS patients, while Danish and Norwegian neurologists have to use other anti-CD20 drugs, as ocrelizumab, in most of the cases.In this paper, we review the pharmacokinetics, pharmacodynamics, clinical efficacy, safety profile and cost effectiveness aspects of RTX for the treatment of MS. Particularly, with the approval of new anti-CD20 DMTs, the recent worldwide COVID-19 emergency and the possible increased risk of infection with this class of drugs, this review sheds light on the use of RTX as an alternative treatment option for MS management, while commenting the gaps of knowledge regarding this drug.

[Ophthalmic manifestations in COVID-19-associated multiple mononeuropathy of the cranial nerves (clinical observation)]

Clinical manifestations of the new coronavirus infection can vary greatly and affect different organs and systems. Despite the lack of convincing data on the possible direct damage to the structures of the eyeball by the SARS-CoV-2 virus, indirect involvement of the organ of vision both in the acute period of the disease, during the period of convalescence, and as a part of the post-COVID syndrome is common in clinical practice. The condition of the ocular surface is not given much attention during the treatment of the main disease, especially in severe cases, which can lead to serious complications and visual acuity loss after recovery. Timely measures can prevent the loss of visual acuity. This article presents a description and discusses a rare case of multiple neuropathy of the cranial nerves associated with COVID-19, with bilateral involvement of the olfactory (I), trigeminal (V), facial (VII) and sublingual (XII) nerves, as well as the right optic nerve (II), which required staged rehabilitation.

Epidemiology, pathophysiology, and classification of the neurological symptoms of post-COVID-19 syndrome

Introduction

Post-COVID-19 syndrome is a series of chronic signs and symptoms that may appear after SARS-CoV-2 infection, including fatigue, dyspnoea, chest pain, palpitations, anxiety, depression, and joint and muscle pain. The purpose of this study was to review the controversies on post-COVID-19 syndrome, the frequency of neurological symptoms, and the potential pathophysiological mechanisms.

Methods

We present a narrative review of studies published in PubMed since the beginning of the pandemic (January 2020-July 2021).

Results

Patients with history of COVID-19 have been found to present persistent neurological symptoms, including cognitive complaints, memory and concentration problems, headache, anosmia, ageusia, vertigo, and insomnia. Post-COVID-19 syndrome is a heterogeneous disease that lacks a universally accepted definition, which may explain the great variability in the estimated prevalence (2.3%-85%) and symptom duration. The criteria differentiating post-COVID-19 syndrome from chronic fatigue syndrome or critical illness syndrome are ambiguous. Risk factors include older age, female sex, certain comorbidities, and greater number of symptoms in the acute phase. The pathophysiology of the syndrome is largely unknown, although it is probably multifactorial, including immunological mechanisms, neural network dysfunction, neurotransmitter alterations, persistent viral damage, and functional impairment.

Conclusions

Post-COVID-19 syndrome may present after mild or even asymptomatic SARS-CoV-2 infection, causing limitations in activities of daily living and in quality of life. Further research will clarify the origin and most appropriate management of these neurological alterations.

Central nervous system as a target of novel coronavirus infections: Potential routes of entry and pathogenic mechanisms

Since the COVID-19 pandemic started in December 2019, there have been several reports of patients succumbing to neurological complications. Early reports were suggestive of a possibility, while by early 2020 it was clearly evident that although SARS-CoV-2 primarily attacks the respiratory system, the brain is one of the most affected organs post-recovery. Although it may be premature to comment on the long-term effects of COVID-19 in brain, some reliable predictions can be made based on the data currently available. Further, exploring the CNS connections of SARS-CoV-2 is of keen interest for neuroscience researchers. As soon as the virus enters the nasal region, it is exposed to the olfactory nervous system which is interlinked with the visual system, and hence we explore the mechanism of entry of this virus into CNS, including brain, olfactory and retinal nervous systems. In this review, we have thoroughly reviewed reports about both SARS-CoV-1 and SARS-CoV-2 with respect to their ability to breach the blood-brain and blood-retinal barriers. We have compiled different neurological conditions resulting from COVID-19 and looked into viral infections related to COVID-19 to understand how the virus may gain control of the olfactory and visual systems. Once the dust settles on the pandemic, it would be interesting to explore the extent of viral infection in the CNS. The long-term effects of this virus in the CNS are not yet known, and several scientific research papers evolving in this field will throw light on the same.

Neurological complications and infection mechanism of SARS-COV-2

Currently, SARS-CoV-2 has caused a global pandemic and threatened many lives. Although SARS-CoV-2 mainly causes respiratory diseases, growing data indicate that SARS-CoV-2 can also invade the central nervous system (CNS) and peripheral nervous system (PNS) causing multiple neurological diseases, such as encephalitis, encephalopathy, Guillain-Barré syndrome, meningitis, and skeletal muscular symptoms. Despite the increasing incidences of clinical neurological complications of SARS-CoV-2, the precise neuroinvasion mechanisms of SARS-CoV-2 have not been fully established. In this review, we primarily describe the clinical neurological complications associated with SARS-CoV-2 and discuss the potential mechanisms through which SARS-CoV-2 invades the brain based on the current evidence. Finally, we summarize the experimental models were used to study SARS-CoV-2 neuroinvasion. These data form the basis for studies on the significance of SARS-CoV-2 infection in the brain.

Facial Diplegia-Complication or Manifestation of SARS-CoV-2 Infection? A Case Report and Systemic Literature Review

Since the outbreak of the new coronavirus, healthcare systems around the world have witnessed not only COVID-19 symptoms but also long-term complications of the aforementioned, including neurological problems. We report a clinical case of an adult patient with bilateral facial nerve palsy and progressive ascending paresis of the limbs after contracting the novel coronavirus (COVID-19). Additionally, the systematic review aimed to identify and summarize specific clinical features, outcomes and complications of the studies focusing on bilateral facial diplegia as a sequela of COVID-19 infection. The total number of analyzed patients was 15. Only one patient was diagnosed with isolated bilateral palsy; the rest had Guillain-Barré Syndrome (GBS). With one exception, all the presented cases had favorable outcomes, with facial palsy recovery from slight to almost complete. In patients with a confirmed COVID-19 diagnosis, bilateral facial palsy may be an isolated symptom as well as a variant of GBS. Symptoms of cranial nerve damage during a COVID-19 infection may explain the appearance of facial nerve damage. In order to clarify the spectrum of neurological manifestations and a causal relation between SARS-CoV-2, COVID-19 vaccination and neurological symptoms, direct attention towards the study of this virus is crucial. It seems reasonable to recognize human coronavirus as another potential GBS trigger.

The Potential Role of COVID-19 in the Pathogenesis of Multiple Sclerosis-A Preliminary Report

Coronavirus 2019 (COVID-19) is an infectious respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that mainly affects the lungs. COVID-19 symptoms include the presence of fevers, dry coughs, fatigue, sore throat, headaches, diarrhea, and a loss of taste or smell. However, it is understood that SARS-CoV-2 is neurotoxic and neuro-invasive and could enter the central nervous system (CNS) via the hematogenous route or via the peripheral nerve route and causes encephalitis, encephalopathy, and acute disseminated encephalomyelitis (ADEM) in COVID-19 patients. This review discusses the possibility of SARS-CoV-2-mediated Multiple Sclerosis (MS) development in the future, comparable to the surge in Parkinson's disease cases following the Spanish Flu in 1918. Moreover, the SARS-CoV-2 infection is associated with a cytokine storm. This review highlights the impact of these modulated cytokines on glial cell interactions within the CNS and their role in potentially prompting MS development as a secondary disease by SARS-CoV-2. SARS-CoV-2 is neurotropic and could interfere with various functions of neurons leading to MS development. The influence of neuroinflammation, microglia phagocytotic capabilities, as well as hypoxia-mediated mitochondrial dysfunction and neurodegeneration, are mechanisms that may ultimately trigger MS development.

Preexisting Mental Disorders Increase the Risk of COVID-19 Infection and Associated Mortality

Coronavirus disease 2019 (COVID-19), a respiratory disease of unknown origin, has a high rate of morbidity and mortality. Individuals with mental disorders may have a higher risk of infection and worse clinical outcomes because of a variety of factors such as poorer general resilience and lower immune function. However, there have been no studies to date specifically investigating the risk of COVID-19 and associated mortality in these patients. This was addressed in the present study by analyzing the data of 473,958 subjects included in the UK Biobank, 14,877 of whom tested positive for COVID-19 infection. Logistic regression analysis was performed to evaluate the associations between mental disorders and risks of COVID-19 infection and associated mortality. The results showed that subjects who were diagnosed with a mental disorder had a significantly higher risk of developing COVID-19 and a worse outcome as evidenced by higher rates of COVID-19-related mortality, with the strongest effects observed for dementia. Among dementia subtypes, Alzheimer disease patients had the highest risks of COVID-19 infection (7.39-fold increase) and associated mortality (2.13-fold increase). Late-life anxiety only increased the risk of developing COVID-19 while late-life depression not only was associated with a higher risk of infection but also a worse outcome. These findings highlight the need to prioritize patients with mental disorders-especially those who experience these disorders later in life-when implementing preventive strategies such as vaccinations.

Nervous System Involvement in COVID-19: a Review of the Current Knowledge

The current pandemic of the new human coronavirus (CoV), i.e., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has created an urgent global condition. The disease, termed coronavirus disease 2019 (COVID-19), is primarily known as a respiratory tract infection. Although SARS-CoV-2 directly invades the lungs, COVID-19 is a complex multi-system disease with varying degrees of severity and affects several human systems including the cardiovascular, respiratory, gastrointestinal, neurological, hematopoietic, and immune systems. From the existing data, most COVID-19 cases develop a mild disease typically presented with fever and respiratory illness. However, in some patients, clinical evidence suggests that COVID-19 might progress to acute respiratory distress syndrome (ARDS), multi-organ dysfunction, and septic shock resulting in a critical condition. Likewise, specific organ dysfunction seems to be related to the disease complication, worsens the condition, and increases the lethality of COVID-19. The neurological manifestations in association with disease severity and mortality have been reported in COVID-19 patients. Despite the continuously increasing reports of the neurological symptoms of SARS-CoV-2, our knowledge about the possible routes of nervous system involvement associated with COVID-19 is limited. Herein, we will primarily describe the critical aspects and clinical features of SARS-CoV-2 related to nervous system impairment and then discuss possible routes of SARS-CoV-2 nervous system involvement based on the current evidence.

High Levels of IL-8 and MCP-1 in Cerebrospinal Fluid of COVID-19 Patients with Cerebrovascular Disease

The coronavirus family has tropism for the Central Nervous System (CNS), however, there is no solid evidence demonstrating that the neurological effects of COVID-19 result from direct viral infection or systemic inflammation. The goals of this study were to examine the cytokine profile and the presence of SARS-CoV-2 messenger ribonucleic acid (mRNA) in cerebrospinal fluids (CSF) from two patients with cerebrovascular disease and COVID-19. Although the SARS-CoV-2 mRNA was not detected in CSF of both patients, we found abnormally high levels of numerous proinflammatory cytokines and chemokines, especially IL-8 and MCP-1. Since these chemokines mediate activation and recruitment of neutrophils, monocytes, and macrophages, it is feasible that cerebrovascular disease related-neuroinflammation found in both patients results from an exacerbated inflammatory response instead of SARS-CoV-2 direct invasion to CNS. These results suggest that neuroinflammation plays a key role in cerebrovascular disease and COVID-19.

Central and peripheral nervous system involvement by COVID-19: a systematic review of the pathophysiology, clinical manifestations, neuropathology, neuroimaging, electrophysiology, and cerebrospinal fluid findings

BACKGROUND

SARS-CoV-2 can affect the human brain and other neurological structures. An increasing number of publications report neurological manifestations in patients with COVID-19. However, no studies have comprehensively reviewed the clinical and paraclinical characteristics of the central and peripheral nervous system's involvement in these patients. This study aimed to describe the features of the central and peripheral nervous system involvement by COVID-19 in terms of pathophysiology, clinical manifestations, neuropathology, neuroimaging, electrophysiology, and cerebrospinal fluid findings.

METHODS

We conducted a comprehensive systematic review of all the original studies reporting patients with neurological involvement by COVID-19, from December 2019 to June 2020, without language restriction. We excluded studies with animal subjects, studies not related to the nervous system, and opinion articles. Data analysis combined descriptive measures, frequency measures, central tendency measures, and dispersion measures for all studies reporting neurological conditions and abnormal ancillary tests in patients with confirmed COVID-19.

RESULTS

A total of 143 observational and descriptive studies reported central and peripheral nervous system involvement by COVID-19 in 10,723 patients. Fifty-one studies described pathophysiologic mechanisms of neurological involvement by COVID-19, 119 focused on clinical manifestations, 4 described neuropathology findings, 62 described neuroimaging findings, 28 electrophysiology findings, and 60 studies reported cerebrospinal fluid results. The reviewed studies reflect a significant prevalence of the nervous system's involvement in patients with COVID-19, ranging from 22.5 to 36.4% among different studies, without mortality rates explicitly associated with neurological involvement by SARS-CoV-2. We thoroughly describe the clinical and paraclinical characteristics of neurological involvement in these patients.

CONCLUSIONS

Our evidence synthesis led to a categorical analysis of the central and peripheral neurological involvement by COVID-19 and provided a comprehensive explanation of the reported pathophysiological mechanisms by which SARS-CoV-2 infection may cause neurological impairment. International collaborative efforts and exhaustive neurological registries will enhance the translational knowledge of COVID-19's central and peripheral neurological involvement and generate therapeutic decision-making strategies.

REGISTRATION

This review was registered in PROSPERO 2020 CRD42020193140 Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020193140.

Geographical Variations in Host Predisposition to COVID-19 Related Anosmia, Ageusia, and Neurological Syndromes

The novel coronavirus disease (COVID-19), has become the most critical global health challenge in recent history. With SARS-CoV-2 infection, there was an unexpectedly high and specific prevalence of olfactory and taste disorders (OTDs). These high rates of hyposmia and hypogeusia, initially reported as up to 89% in European case series, led to the global inclusion of loss of taste and/or smell as a distinctive feature of COVID-19. However, there is emerging evidence that there are striking differences in the rates of OTDs in East Asian countries where the disease first emerged, as compared to Western countries (15.8 vs. 60.9%, p-value < 0.01). This may be driven by either variations in SARS-CoV-2 subtypes presenting to different global populations or genotypic differences in hosts which alter the predisposition of these different populations to the neuroinvasiveness of SARS-CoV-2. We also found that rates of OTDs were significantly higher in objective testing for OTDs as compared to subjective testing (73.6 vs. 60.8%, p-value = 0.03), which is the methodology employed by most studies. Concurrently, it has also become evident that racial minorities across geographically disparate world populations suffer from disproportionately higher rates of COVID-19 infection and mortality. In this mini review, we aim to delineate and explore the varying rates of olfactory and taste disorders amongst COVID-19 patients, by focusing on their underlying geographical, testing, ethnic and socioeconomic differences. We examine the current literature for evidence of differences in the olfactory and gustatory manifestations of COVID-19 and discuss current pathophysiological hypotheses for such differences.

COVID-19 anosmia and gustatory symptoms as a prognosis factor: a subanalysis of the HOPE COVID-19 (Health Outcome Predictive Evaluation for COVID-19) registry

Olfactory and gustatory dysfunctions (OGD) are a frequent symptom of coronavirus disease 2019 (COVID-19). It has been proposed that the neuroinvasive potential of the novel SARS-CoV-2 could be due to olfactory bulb invasion, conversely studies suggest it could be a good prognostic factor. The aim of the current study was to investigate the prognosis value of OGD in COVID-19. These symptoms were recorded on admission from a cohort study of 5868 patients with confirmed or highly suspected COVID-19 infection included in the multicenter international HOPE Registry (NCT04334291). There was statistical relation in multivariate analysis for OGD in gender, more frequent in female 12.41% vs 8.67% in male, related to age, more frequent under 65 years, presence of hypertension, dyslipidemia, diabetes, smoke, renal insufficiency, lung, heart, cancer and neurological disease. We did not find statistical differences in pregnant (p = 0.505), patient suffering cognitive (p = 0.484), liver (p = 0.1) or immune disease (p = 0.32). There was inverse relation (protective) between OGD and prone positioning (0.005) and death (< 0.0001), but no with ICU (0.165) or mechanical ventilation (0.292). On univariable logistic regression, OGD was found to be inversely related to death in COVID-19 patients. The odds ratio was 0.26 (0.15-0.44) (p < 0.001) and Z was - 5.05. The presence of anosmia is fundamental in the diagnosis of SARS.CoV-2 infection, but also could be important in classifying patients and in therapeutic decisions. Even more knowing that it is an early symptom of the disease. Knowing that other situations as being Afro-American or Latino-American, hypertension, renal insufficiency, or increase of C-reactive protein (CRP) imply a worse prognosis we can make a clinical score to estimate the vital prognosis of the patient. The exact pathogenesis of SARS-CoV-2 that causes olfactory and gustative disorders remains unknown but seems related to the prognosis. This point is fundamental, insomuch as could be a plausible way to find a treatment.

Stroke in patients infected by the novel coronavirus and its causal mechanisms: A narrative review

OBJECTIVE

The current study aimed to evaluate the mechanisms of stroke development during the coronavirus disease 2019 (COVID-19) pandemic and analyze the related characteristics, such as etiology, age group, associated comorbidities, and prognosis.

METHODS

A narrative was performed using the descriptors ["novel coronavirus"] AND ["stroke"] in the PubMed, Science Direct, Google Scholar, Lilacs, and Biblioteca Virtual em Saúde (BVS) databases, including studies published between December 1, 2019, and April 28, 2020.

RESULTS

A total of 142 articles were identified, with 89 of them in the PubMed database, 46 in Science Direct, and 7 in Google Scholar. No articles were found using the defined keywords in the Lilacs and BVS databases. A total of 22 articles were included for final evaluation. We observed that infection by the novel coronavirus caused a greater risk of the occurrence of stroke, with several studies suggesting etiological mechanisms, such as the involvement of angiotensin-converting enzyme 2, viral invasion, and hypoxia as well as the increase in D-dimer and the reduction in platelets, which had been commonly observed in COVID-19 cases. The most common complication of stroke was found among the elderly with preexisting comorbidities, mainly cardiovascular disease. We detected reports of strokes among young people with no preexisting risk factors for thromboembolic events, in which the mechanism related to the viral infection was the most probable cause. In this review, we confirmed that stroke is part of the spectrum of clinical manifestations resulting from COVID-19 and is associated with a worse prognosis. Cerebrovascular lesions resulting from complications of the infection by the novel coronavirus occurred as a result of ischemic, hemorrhagic, and/or thromboembolic etiologies.

CONCLUSION

The occurrence of stroke during the pandemic as a result of the novel coronavirus has a multifactorial character, and emergency physicians should focus on systematic measures for its screening and accurate diagnosis as well as on appropriate interventions based on early decisionmaking that may have a favorable impact on reducing damage and saving lives.

Infection Mechanism of SARS-COV-2 and Its Implication on the Nervous System

In late December 2019, multiple atypical pneumonia cases resulted in severe acute respiratory syndrome caused by a pathogen identified as a novel coronavirus SARS-CoV-2. The most common coronavirus disease 2019 (COVID-19) symptoms are pneumonia, fever, dry cough, and fatigue. However, some neurological complications following SARS-CoV-2 infection include confusion, cerebrovascular diseases, ataxia, hypogeusia, hyposmia, neuralgia, and seizures. Indeed, a growing literature demonstrates that neurotropism is a common feature of coronaviruses; therefore, the infection mechanisms already described in other coronaviruses may also be applicable for SARS-CoV-2. Understanding the underlying pathogenetic mechanisms in the nervous system infection and the neurological involvement is essential to assess possible long-term neurological alteration of COVID-19. Here, we provide an overview of associated literature regarding possible routes of COVID-19 neuroinvasion, such as the trans-synapse-connected route in the olfactory pathway and peripheral nerve terminals and its neurological implications in the central nervous system.

The neuropathological impact of COVID-19: a review

BACKGROUND

The Coronavirus disease 2019 (COVID-19) outbreak has become a challenging global issue after its emergence in December 2019. Due to the high adaptation of the virus, COVID-19 demonstrated a high transmission and infectivity potentials. Several studies demonstrated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induce deleterious neurological manifestations through interacting with the central nervous system (CNS).

MAIN BODY

The neuroinvasive potential of SARS-CoV-2 might contribute to its fatal behavior. Understanding the underlying mechanisms of this novel neuropathogen might contribute to the development of effective therapeutic strategies. The manifestations of neural damage in COVID-19 patients ranged from headache to severe encephalopathy and progression of preexisting neural disorders, it is speculated that neuroinvasion is strongly linked to the fatal respiratory dysfunction. The underlying neuropathological impact of emerging pneumonia (COVID-19) is still unclear.

CONCLUSION

This review demonstrated the urgent need to understand the neuropathology of COVID-19, to manage the current borderless viral outbreak of SARS-CoV-2 and its comorbidities. Moreover, SARS-CoV-2 could be regarded as an opportunistic neuropathogen that affects several vital functions in the human body.

Genetic Diversity of SARS-CoV2 and Environmental Settings: Possible Association with Neurological Disorders

The new coronavirus (CoV), called novel coronavirus disease 2019 (COVID-19), belongs to the Coronaviridae family which was originated from the sea market in Wuhan city in China, at the end of the year 2019. COVID-19 and severe acute respiratory syndrome (SARS) are belonging to the same family (Coronaviridae). The current outbreak of COVID-19 creates public concern and threats all over the world and now it spreads out to more than 250 countries and territories. The researchers and scientists from all over the world are trying to find out the therapeutic strategies to abate the morbidity and mortality rate of the COVID-19 pandemic. The replication, spreading, and severity of SARS-CoV2 depend on environmental settings. Noteworthy, meteorological parameters are considered as crucial factors that affect respiratory infectious disorders, although the controversial effect of the meteorological parameter is exposed against COVID-19. Besides, COVID-19 accelerates the pathogenesis of the neurological disorders. However, the pathogenic mechanisms between COVID-19 and neurological disorders are still unclear. Hence, this review is focused on the genomics and ecology of SARS-CoV2 and elucidated the effects of climatic factors on the progression of COVID-19. This review also critically finds out the vulnerability between COVID-19 and neurological disorders based on the latest research data.

Combating COVID-19 with tissue engineering: a review

The ongoing COVID-19 pandemic triggered by SARS-CoV-2 emerged from Wuhan, China, firstly in December 2019, as well spread to almost all around the world rapidly. The main reason why this disease spreads so many people in a short time is that the virus could be transmitted from an infected person to another by infected droplets. The new emergence of diseases usually may affect multiple organs; moreover, this disease is such an example. Numerous reported studies focus on acute or chronic organ damage caused by the virus. At this point, tissue engineering (TE) strategies can be used to treat the damages with its interdisciplinary approaches. Tissue engineers could design drug delivery systems, scaffolds, and especially biomaterials for the damaged tissue and organs. In this review, brief information about SARS-CoV-2, COVID-19, and epidemiology of the disease will be given at first. After that, the symptoms, the tissue damages in specific organs, and cytokine effect caused by COVID-19 will be described in detail. Finally, it will be attempted to summarize and suggest the appropriate treatments with suitable biomaterials for the damages via TE approaches. The aim of this review is to serve as a summary of currently available tissue damage treatments after COVID-19.

Viral infections and their relationship to neurological disorders

The chronic dysfunction of neuronal cells, both central and peripheral, a characteristic of neurological disorders, may be caused by irreversible damage and cell death. In 2016, more than 276 million cases of neurological disorders were reported worldwide. Moreover, neurological disorders are the second leading cause of death. Generally, the etiology of neurological diseases is not fully understood. Recent studies have related the onset of neurological disorders to viral infections, which may cause neurological symptoms or lead to immune responses that trigger these pathological signs. Currently, this relationship is mostly based on epidemiological data on infections and seroprevalence of patients who present with neurological disorders. The number of studies aiming to elucidate the mechanism of action by which viral infections may directly or indirectly contribute to the development of neurological disorders has been increasing over the years but these studies are still scarce. Comprehending the pathogenesis of these diseases and exploring novel theories may favor the development of new strategies for diagnosis and therapy in the future. Therefore, the objective of the present study was to review the main pieces of evidence for the relationship between viral infection and neurological disorders such as Alzheimer's disease, Parkinson's disease, Guillain-Barré syndrome, multiple sclerosis, and epilepsy. Viruses belonging to the families Herpesviridae, Orthomyxoviridae, Flaviviridae, and Retroviridae have been reported to be involved in one or more of these conditions. Also, neurological symptoms and the future impact of infection with SARS-CoV-2, a member of the family Coronaviridae that is responsible for the COVID-19 pandemic that started in late 2019, are reported and discussed.

Prevalence of neurological manifestations in COVID-19 and their association with mortality

Introduction

Articles published in the literature report neurological manifestations or "complications" of SARS-CoV-2 infection and conclude that the different neurological manifestations are relatively similar, but with different frequencies. This study aimed to determine the frequency of neurological manifestations of COVID-19 and to identify which are associated with mortality.

Methods

We performed a retrospective study of all patients diagnosed with SARS-CoV-2 infection by RT-PCR at Hospital 1° de Octubre, in Mexico, from the beginning of the pandemic to 22 December 2020. A total of 561 patients were identified, 370 of whom presented neurological manifestations.

Results

The global mortality rate was 37.8% (140/370), increasing to 92.4% among intubated patients (135/146). Of the 370 patients included, approximately 20% of neurological symptoms (headache, neurological impairment, anosmia, ageusia) accounted for 80% of cases of neurological manifestations.

Conclusions

At our hospital, 80% of the patients with neurological manifestations of COVID-19 presented headache, neurological impairment, ageusia, and/or anosmia. Neurological impairment at admission or before arriving at hospital was identified as a risk factor for mortality.

Neurological and neurocognitive alterations by COVID-19

Letters to the editor

Can the coronavirus infection penetrates the brain resulting in sudden anosmia followed by severe neurological disorders?

Serious of unpredictable drawbacks of Coronavirus 2019 (COVID-19) infectious disease caused by SARS-COV-2 on the nervous system, have been widely noticed among the huge number of infected people. It was found that this type of newly revolving pandemic infection mainly infects the human respiratory tract causing mild to moderate symptoms, however, the hidden door side of COVID-19 is via penetrating the brain, revealing a huge threat especially to elderly people who are more susceptible to its severe side effects and even death to more extent. Almost 80% of COVID-19 patients suffer from severe neurological manifestations including dizziness, headache, unconscious, irritability, dysfunction in smell, and taste accompanied by muscle fatigue. Herein, we are trying to address the direct neuroinvasive pathway of COVID-19 into human brain cells which is mainly through the olfactory route leading to long-term neurological complications. In addition to highlighting the ability of COVID-19 infection to intensify a pre-existing AD to a more prominent severe stage. The other thing to emphasize is whether AD patients with a highly prominent activation of local immune responses are more or less exposed to getting infected with COVID-19. Along with underlying the hypothesis that the susceptibility to COVID-19 infection may lead to a future risk for neurodegenerative diseases including Alzheimer's disease (AD).

A 30-year-old male with COVID-19 presenting with seizures and leukoencephalopathy

First reported in Wuhan, China, Novel Coronavirus Disease-19 rapidly spread causing an outbreak of viral pneumonia and became a pandemic in early 2020. It was later discovered to be caused by Severe Acute Respiratory Syndrome Coronavirus 2, a novel coronavirus. Although the vast majority of cases have primarily involved the respiratory system, some serious cases have started to emerge with central and peripheral nervous system complications. We present the case of a 30-year-old morbidly obese male who initially presented to the emergency department with seizures, altered mental status, and COVID-19 pneumonia. After a 21-day hospital course including 14 days of intensive care unit management, he was stabilized and discharged to a rehabilitation facility. He returned 1 day later with worsening respiratory distress and was found to have acute pulmonary embolism requiring placement of an inferior vena cava filter. After an additional 6 days in the hospital, he was discharged back to the outpatient facility. He returned for a third time with altered mental status, visual and auditory hallucinations, and confabulation. This report provides critical information in revealing a peculiar neurological sequela of COVID-19 induced leukoencephalopathy and its disease course. We hope to shed light on this sequence of events by providing possible mechanisms to aid clinicians in the identification and management of this complication.

Dyspneic and non-dyspneic (silent) hypoxemia in COVID-19: Possible neurological mechanism

SARS-CoV-2 mainly invades respiratory epithelial cells by adhesion to angiotensin-converting enzyme 2 (ACE-2) and thus, infected patients may develop mild to severe inflammatory responses and acute lung injury. Afferent impulses that result from the stimulation of pulmonary mechano-chemoreceptors, peripheral and central chemoreceptors by inflammatory cytokines are conducted to the brainstem. Integration and processing of these input signals occur within the central nervous system, especially in the limbic system and sensorimotor cortex, and importantly feedback regulation exists between O₂, CO_2, and blood pH. Despite the intensity of hypoxemia in COVID-19, the intensity of dyspnea sensation is inappropriate to the degree of hypoxemia in some patients (silent hypoxemia). We hypothesize that SARS-CoV-2 may cause neuronal damage in the corticolimbic network and subsequently alter the perception of dyspnea and the control of respiration. SARS-CoV-2 neuronal infection may change the secretion of numerous endogenous neuropeptides or neurotransmitters that distribute through large areas of the nervous system to produce cellular and perceptual effects. SARS-CoV-2 mainly enter to CNS via direct (neuronal and hematologic route) and indirect route. We theorize that SARS-CoV-2 infection-induced neuronal cell damage and may change the balance of endogenous neuropeptides or neurotransmitters that distribute through large areas of the nervous system to produce cellular and perceptual effects. Thus, SARS-CoV-2-associated neuronal damage may influence the control of respiration by interacting in neuromodulation. This would open up possible lines of study for the progress in the central mechanism of COVID-19-induced hypoxia. Future research is desirable to confirm or disprove such a hypothesis.

[Smell and taste disorders in Spanish patients with mild COVID-19]

Introduction

Coronavirus disease 2019 (COVID-19) has spread rapidly throughout the world. Smell and/or taste disorders have emerged as a very frequent symptom as the disease has spread in Europe. Spain is one of the European countries with the highest number of infections.

Objective

This study aimed to investigate the clinical progression of smell and taste disorders in Spanish patients with mild COVID-19.

Methods

An online survey was used to conduct a cross-sectional study of patients who presented sudden smell and/or taste disorders during the 2 months of total lockdown due to COVID-19 in Spain.

Results

In our sample, 91.18% of respondents with impaired smell and/or taste and who were able to undergo PCR testing were positive for SARS-CoV-2 infection. Anosmia and ageusia presented in isolation in 6.5% of participants. The remaining 93.5% presented other mild symptoms: headache (51.6%), cough (51.6%), myalgia (45.2%), asthaenia (38.7%), nasal congestion or rhinorrhoea (35.5%), fever (41.9%), low-grade fever (29.0%), odynophagia (25.8%), or diarrhoea (6.5%). The mean duration of anosmia was 8.33 days, with patients subsequently manifesting hyposmia; complete resolution occurred after a mean of 17.79 days. In 22.6% of respondents, olfactory deficits persisted. All participants recovered their sense of taste.

Conclusions

Olfactory and gustatory disorders are prevalent symptoms in mild COVID-19. Most patients do not present associated nasal congestion or rhinorrhoea and a small group of patients present these alterations in isolation.

Smell and taste disorders in Spanish patients with mild COVID-19

Introduction

Coronavirus disease 2019 (COVID-19) has spread rapidly throughout the world. Smell and/or taste disorders have emerged as a very frequent symptom as the disease has spread in Europe. Spain is one of the European countries with the highest number of infections.

Objective

This study aimed to investigate the clinical progression of smell and taste disorders in Spanish patients with mild COVID-19.

Methods

An online survey was used to conduct a cross-sectional study of patients who presented sudden smell and/or taste disorders during the 2 months of total lockdown due to COVID-19 in Spain.

Results

In our sample, 91.18% of respondents with impaired smell and/or taste and who were able to undergo PCR testing were positive for SARS-CoV-2 infection. Anosmia and ageusia presented in isolation in 6.5% of participants. The remaining 93.5% presented other mild symptoms: headache (51.6%), cough (51.6%), myalgia (45.2%), asthaenia (38.7%), nasal congestion or rhinorrhoea (35.5%), fever (41.9%), low-grade fever (29.0%), odynophagia (25.8%), or diarrhoea (6.5%). The mean duration of anosmia was 8.33 days, with patients subsequently manifesting hyposmia; complete resolution occurred after a mean of 17.79 days. In 22.6% of respondents, olfactory deficits persisted. All participants recovered their sense of taste.

Conclusions

Olfactory and gustatory disorders are prevalent symptoms in mild COVID-19. Most patients do not present associated nasal congestion or rhinorrhoea and a small group of patients present these alterations in isolation.

Brain and COVID-19 Crosstalk: Pathophysiological and Psychological Manifestations

The world is experiencing one of the major viral outbreaks of this millennium, caused by a plus sense single-stranded RNA virus belonging to the Coronaviridae family, COVID-19, declared as pandemic by WHO. The clinical manifestations vary from asymptomatic to mild symptoms like fever, dry cough, and diarrhea, with further increase in severity leading to the development of acute respiratory distress syndrome. Though primary manifestations are respiratory and cardiac, various studies have shown the neuroinvasive capability of this virus resulting in neurological complications, which sometimes can precede common typical symptoms like fever and cough. Common neurological symptoms are headache, dizziness, anosmia, dysgeusia, confusion, and muscle weakening, progressing toward severe complications like cerebrovascular disease, seizures, or paralysis. Older adults and critically ill people are in the high risk group and have shown severe neurological symptoms upon infection. COVID-19 also has a profound impact on the mental health of people across the world. In this review, we briefly discuss the neurological pathologies and psychological impact due to COVID-19, which has not only stressed the physical health of people but has also created social and economic problems resulting in mental health issues.

Neuroinvasion and Viral Reservoir in COVID-19

The new coronavirus disease 2019 (COVID-19) has a remarkably high transmissibility potential and sometimes invades the central nervous system (CNS). The study of the involvement of the nervous system in the pathogenesis of the disease is especially interesting. Currently, there are only three main theories about it: direct neuroinvasion; blood-brain barrier (BBB) crossing and nicotinic hypothesis. Because of the rapid expansion of a virus that until now was unknown, it is necessary to know the mechanisms by which severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2) generates the disease. The study of the involvement of the nervous system in the pathogenesis of the disease is especially interesting, since it is the least studied question with more innovative theories that could explain not only neurological complications, but also the primary infection and the involvement of the various organs and systems.

Manifestaciones neurológicas de COVID-19: Una revisión de la literatura

La COVID-19 es la infección causada por un nuevo coronavirus (SARS-CoV-2) y se ha extendido rápidamente por todo el mundo desde que se reportaron los primeros casos en China en diciembre de 2019.

Los pacientes con COVID-19 tienen un amplio espectro de manifestaciones clínicas, desde formas asintomáticas hasta cuadros muy graves de distrés respiratorio y falla multiorgánica. Las manifestaciones neurológicas se han reportado hasta en el 36,4% de pacientes con COVID-19 e incluyen cefalea, mareos, alteración de la conciencia y convulsiones. Así mismo, se han reportado casos de encefalitis, accidente cerebrovascular y síndrome de Guillain-Barré asociado a COVID-19.

Las manifestaciones neurológicas de COVID-19 pueden deberse a varios mecanismos, como la invasión directa (por las propiedades neurotrópicas del virus) y a mecanismos indirectos (derivados del estado proinflamatorio, de las alteraciones metabólicas o de la desregulación del sistema inmune). Se realizó una revisión de la literatura de los aspectos clínicos neurológicos de COVID-19 y sus manifestaciones neurológicas.

Chronic neurological diseases and COVID-19: Associations and considerations

The 2019 novel coronavirus pandemic, severe acute respiratory syndrome CoV-2 (COVID-19), has been a worldwide urgent public health threat, resulting in six-hundred seventy thousand deaths to date. The COVID-19 pandemic has led to a series of public health challenges. One such challenge is the management of diseases such as chronic neurological diseases during an epidemic event. COVID-19 affects all kinds of people, including older people with chronic underlying diseases, who are particularly at risk of severe infection or even death. Chronic neurological diseases such as epilepsy, dementia, Parkinson's disease (PD), and multiple sclerosis (MS) are frequently associated with comorbidities; thus, these patients are in the high-risk category. Therefore, in this article, we review associations and challenges the people with epilepsy, dementia, PD, and MS faces during the COVID-19 pandemic and suggest approaches to provide consensus recommendations on how to provide the best possible care.

Coronaviruses: a challenge of today and a call for extended human postmortem brain analyses

While there is abounding literature on virus-induced pathology in general and coronavirus in particular, recent evidence accumulates showing distinct and deleterious brain affection. As the respiratory tract connects to the brain without protection of the blood-brain barrier, SARS-CoV-2 might in the early invasive phase attack the cardiorespiratory centres located in the medulla/pons areas, giving rise to disturbances of respiration and cardiac problems. Furthermore, brainstem regions are at risk to lose their functional integrity. Therefore, long-term neurological as well as psychiatric symptomatology and eventual respective disorders cannot be excluded as evidenced from influenza-A triggered post-encephalitic Parkinsonism and HIV-1 triggered AIDS-dementia complex. From the available evidences for coronavirus-induced brain pathology, this review concludes a number of unmet needs for further research strategies like human postmortem brain analyses. SARS-CoV-2 mirroring experimental animal brain studies, characterization of time-dependent and region-dependent spreading behaviours of coronaviruses, enlightening of pathological mechanisms after coronavirus infection using long-term animal models and clinical observations of patients having had COVID-19 infection are calling to develop both protective strategies and drug discoveries to avoid early and late coronavirus-induced functional brain disturbances, symptoms and eventually disorders. To fight SARS-CoV-2, it is an urgent need to enforce clinical, molecular biological, neurochemical and genetic research including brain-related studies on a worldwide harmonized basis.

Experimental Models for the Study of Central Nervous System Infection by SARS-CoV-2

INTRODUCTION

The response to the SARS-CoV-2 coronavirus epidemic requires increased research efforts to expand our knowledge of the disease. Questions related to infection rates and mechanisms, the possibility of reinfection, and potential therapeutic approaches require us not only to use the experimental models previously employed for the SARS-CoV and MERS-CoV coronaviruses but also to generate new models to respond to urgent questions.

DEVELOPMENT

We reviewed the different experimental models used in the study of central nervous system (CNS) involvement in COVID-19 both in different cell lines that have enabled identification of the virus' action mechanisms and in animal models (mice, rats, hamsters, ferrets, and primates) inoculated with the virus. Specifically, we reviewed models used to assess the presence and effects of SARS-CoV-2 on the CNS, including neural cell lines, animal models such as mouse hepatitis virus CoV (especially the 59 strain), and the use of brain organoids.

CONCLUSION

Given the clear need to increase our understanding of SARS-CoV-2, as well as its potential effects on the CNS, we must endeavor to obtain new information with cellular or animal models, with an appropriate resemblance between models and human patients.

Reorganization of multiple sclerosis health care system in Clinical Centre of Montenegro during the COVID-19 pandemic

The COVID-19 epidemic has brought a number of changes to health systems, including the provision of health services to patients with multiple sclerosis (MS). Work in the Clinic for Neurology of the Clinical Center of Montenegro (CN-CCM) with MS patients continued as much as possible during the epidemic. The administration of the already started disease-modifying therapy (DMT) continued, and the introduction of the new one was postponed until the moment when the epidemic started to slow down. During the epidemic period, plasmapheresis treatment was performed in CN-CCM without any complications. New ways of communications (special e-mail address and phone line) with MS patients during epidemic were realized. During epidemic, smaller number of relapses were reported compared to same period in 2019. There were not MS patients in Montenegro suffering from SARS-Cov2 virus infection.