Update on Viral Infections Involving the Central Nervous System in Pediatric Patients.

Infections of the central nervous system (CNS) are mainly caused by viruses, and these infections can be life-threatening in pediatric patients. Although the prognosis of CNS infections is often favorable, mortality and long-term sequelae can occur. The aims of this narrative review were to describe the specific microbiological and clinical features of the most frequent pathogens and to provide an update on the diagnostic approaches and treatment strategies for viral CNS infections in children. A literature analysis showed that the most common pathogens worldwide are enteroviruses, arboviruses, parechoviruses, and herpesviruses, with variable prevalence rates in different countries. Lumbar puncture (LP) should be performed as soon as possible when CNS infection is suspected, and cerebrospinal fluid (CSF) samples should always be sent for polymerase chain reaction (PCR) analysis. Due to the lack of specific therapies, the management of viral CNS infections is mainly based on supportive care, and empiric treatment against herpes simplex virus (HSV) infection should be started as soon as possible. Some researchers have questioned the role of acyclovir as an empiric antiviral in older children due to the low incidence of HSV infection in this population and observed that HSV encephalitis may be clinically recognizable beyond neonatal age. However, the real benefit-risk ratio of selective approaches is unclear, and further studies are needed to define appropriate indications for empiric acyclovir. Research is needed to find specific therapies for emerging pathogens. Moreover, the appropriate timing of monitoring neurological development, performing neuroimaging evaluations and investigating the effectiveness of rehabilitation during follow-up should be evaluated with long-term studies.

Towards Neuro-CoViD-19.

CoViD-19 is the current pandemic caused by the Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2). Infection by SARS-CoV-2 occurs via the binding of its S protein to the angiotensin-converting enzyme-2 receptor (ACE2-R). S binding to ACE2-R leads to a drop in ACE2, a homolog of angiotensin converting enzyme (ACE). In the central nervous system (CNS), ACE mediates neuroinflammation, neurodegeneration and neurotoxicity responsible for several CNS disorders. ACE2 counteracts the damaging effects of ACE on CNS neurons. SARS-CoV-2 can directly access the CNS via the circulation or via cranial nerve I and the olfactory bulb. Inactivation of ACE2 following binding of SARS-CoV-2 S protein to ACE2-R in situ might blunt ACE2-moderating effects upon ACE CNS neurotoxicity and neurodegeneration. Here, we propose a neurobiological mechanism directly involving SARS-CoV-2 binding to ACE2-R in the etiology of putative Neuro-CoViD-19.

COVID-19 and the central nervous system: What is the interplay?

Since the outbreak of COVID-19 in 2019-2020, the highly contiguous disease caused by coronavirus 2 (SARS-CoV-2) spread worldwide in a short life span causing a disastrous effect and nearly 5.8 million deaths until February 2022. This global health crisis caused concerns about the disease's aetiology, epidemiology, and management. Understanding the virus's long-and short-term consequences on diverse human body organs and systems was one of the scientist's concerns despite the virus' respiratory system principal effect. Thus, after reporting neurological symptoms in approximately one-third of hospitalised patients with COVID-19, demonstrating how COVID-19 infects the central nervous system (CNS), causing neurodegenerative diseases in various patients and how the virus affects CNS function became quintessential. There are various mechanisms for COVID-19 pathophysiology, some implicating the potential virus invasion of the blood-brain barrier (BBB). Trans-synaptic and hematogenous routes are the main routes for the virus to pass through the barrier. Binding to the BBB endothelial cells is causing significant alterations in the permeability and integrity properties of the barrier, which cause an elevation of the incidence rate of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis among COVI-19 patients. COVID-19 patients developed neurological manifestations ranging from mild symptoms to severe diseases such as headache and loss of smell, encephalitis and CNS-mediated respiratory distress. However, encephalitis is not a common complication, and it has a significant mortality rate in severely ill patients due to the hyperactivation of the host immune response. Although more investigations are needed, severe COVID-19 patients are considered at a high risk of neurodegenerative disorder as a long-term consequence of SARS-CoV-2 infection. © 2022, Neurotak Publishing. All rights reserved.

Case report: Lympho-histiocytic meningoencephalitis with central nervous system vasculitis of unknown origin in three dogs.

Meningoencephalitis of unknown origin (MUO) is an umbrella term for a variety of subtypes of meningoencephalitis of dogs and cats with no identifiable infectious agent. In dogs, granulomatous meningoencephalitis (GME), necrotizing meningoencephalitis (NME), and necrotizing leukoencephalitis (NLE) are the most commonly reported subtypes. However, sporadically there are reports about other subtypes such as greyhound encephalitis or eosinophilic meningoencephalitis. The following case series presents three dogs with peracute to acute progressive signs of encephalopathy. The magnetic resonance imaging (MRI) of two dogs (post mortem n = 1/2) showed severe, diffuse swelling of the cortical gray matter with increased signal intensity in T2weighted (w) and fluid-attenuated inversion recovery (FLAIR) and decreased signal intensity in T1w. Additionally, focal to multifocal areas with signal void in both dogs and caudal transforaminal herniation of the cerebellum in one dog was observed. Post mortem histopathological examination revealed lympho-histiocytic encephalitis and central nervous system (CNS) vasculitis in all dogs. No infectious agents were detectable by histopathology (hematoxylin and eosin stain), periodic acid-Schiff reaction (PAS), Ziehl-Neelsen stain and immunohistochemistry for Canine adenovirus-1, Parvovirus, Listeria monocytogenes, Parainfluenzavirus, Toxoplasma gondii, Herpes-suis virus, Pan-Morbillivirus, Tick born encephalitis virus, Severe acute respiratory syndrome coronavirus (SARS-CoV) 2. Furthermore, two dogs were tested negative for rabies virus. To the best of the authors' knowledge, this is the first report of a lympho-histiocytic encephalitis with CNS vasculitis with no identifiable infectious agent. It is suggested to consider this as an additional subtype of MUO with severe clinical signs.

A Systematic Review of Neurological Manifestations of COVID-19.

The coronavirus can infect the upper respiratory tract, sinuses, and nose, and its severity manifests in its respiratory symptoms and neurological and psychological consequences. The majority of people who have COVID-19 present with moderate flu-like illness, and patients who are elderly with comorbid conditions, such as hypertension and diabetes, are more prone to experience severe illness and death. However, in the ongoing COVID-19 pandemic, neurological consequences have become a substantial source of morbidity and mortality. COVID-19 poses a global hazard to the nervous system because of its widespread dispersion and multiple pathogenic pathways. This review offers a critical assessment of the acute and long-term neurological effects of the COVID-19 virus. Some neurological problems include headache, dizziness, myalgia/fatigue, meningitis, ischemic/hemorrhagic stroke, and myelitis. Other people who have contracted COVID-19 also exhibit neurological features such as loss of taste and smell, reduced consciousness, and Guillain-Barré syndrome. This study seeks to help neurologists comprehend the wide range of neurologic aspects of COVID-19, as understanding neurological symptoms may help with the management and enhance the patient's outcomes.

Tangled quest of post-COVID-19 infection-caused neuropathology and what 3P nano-bio-medicine can solve?

COVID-19-caused neurological problems are the important post-CoV-2 infection complications, which are recorded in ~ 40% of critically ill COVID-19 patients. Neurodegeneration (ND) is one of the most serious complications. It is necessary to understand its molecular mechanism(s), define research gaps to direct research to, hopefully, design new treatment modalities, for predictive diagnosis, patient stratification, targeted prevention, prognostic assessment, and personalized medical services for this type of complication. Individualized nano-bio-medicine combines nano-medicine (NM) with clinical and molecular biomarkers based on omics data to improve during- and post-illness management or post-infection prognosis, in addition to personalized dosage profiling and drug selection for maximum treatment efficacy, safety with least side-effects. This review will enumerate proteins, receptors, and enzymes involved in CoV-2 entrance into the central nervous system (CNS) via the blood-brain barrier (BBB), and list the repercussions after that entry, ranging from neuroinflammation to neurological symptoms disruption mechanism. Moreover, molecular mechanisms that mediate the host effect or viral detrimental effect on the host are discussed here, including autophagy, non-coding RNAs, inflammasome, and other molecular mechanisms of CoV-2 infection neuro-affection that are defined here as hallmarks of neuropathology related to COVID-19 infection. Thus, a couple of questions are raised; for example, "What are the hallmarks of neurodegeneration during COVID-19 infection?" and "Are epigenetics promising solution against post-COVID-19 neurodegeneration?" In addition, nano-formulas might be a better novel treatment for COVID-19 neurological complications, which raises one more question, "What are the challenges of nano-bio-based nanocarriers pre- or post-COVID-19 infection?" especially in the light of omics-based changes/challenges, research, and clinical practice in the framework of predictive preventive personalized medicine (PPPM / 3P medicine).

Screening for Viral Nucleic Acids in the Cerebrospinal Fluid of Dogs With Central Nervous System Inflammation.

Central nervous system (CNS) inflammation is a common cause of neurological dysfunction in dogs. Most dogs with CNS inflammation are diagnosed with presumptive autoimmune disease. A smaller number are diagnosed with an infectious etiology. Additionally, at necropsy, a subset of dogs with CNS inflammation do not fit previously described patterns of autoimmune disease and an infectious cause is not readily identifiable. Because viral infection is a common cause of meningoencephalitis in people, we hypothesize that a subset of dogs presented with CNS inflammation have an occult viral infection either as a direct cause of CNS inflammation or a trigger for autoimmunity. The goal of this research was to screen cerebrospinal fluid from a large number dogs with CNS inflammation for occult viral infection. One hundred seventy-two dogs with neurological dysfunction and cerebrospinal fluid (CSF) pleocytosis were identified. Of these, 42 had meningoencephalitis of unknown origin, six had steroid-responsive meningitis-arteritis, one had eosinophilic meningoencephalitis, five had documented infection, 21 had and undetermined diagnosis, and 97 had a diagnosis not consistent with primary inflammatory disease of the CNS (e.g., neoplasia). CSF samples were subsequently screened with broadly reactive PCR for eight viral groups: adenovirus, bunyavirus, coronavirus, enterovirus, flavivirus, herpesvirus, paramyxovirus, and parechovirus. No viral nucleic acids were detected from 168 cases screened for eight viral groups, which does not support occult viral infection as a cause of CNS inflammation in dogs. La Crosse virus (LACV) nucleic acids were detected from four cases in Georgia. Subclinical infection was supported in two of these cases but LACV could not be ruled-out as a cause of infection in the other two cases, suggesting further research is warranted to determine if LACV is an occult cause of CNS inflammation in dogs.

Nutraceuticals in HIV and COVID-19-Related Neurological Complications: Opportunity to Use Extracellular Vesicles as Drug Delivery Modality.

People living with HIV/AIDS (PLWHA) are at an increased risk of severe and critical COVID-19 infection. There is a steady increase in neurological complications associated with COVID-19 infection, exacerbating HIV-associated neurocognitive disorders (HAND) in PLWHA. Nutraceuticals, such as phytochemicals from medicinal plants and dietary supplements, have been used as adjunct therapies for many disease conditions, including viral infections. Appropriate use of these adjunct therapies with antiviral proprieties may be beneficial in treating and/or prophylaxis of neurological complications associated with these co-infections. However, most of these nutraceuticals have poor bioavailability and cannot cross the blood-brain barrier (BBB). To overcome this challenge, extracellular vesicles (EVs), biological nanovesicles, can be used. Due to their intrinsic features of biocompatibility, stability, and their ability to cross BBB, as well as inherent homing capabilities, EVs hold immense promise for therapeutic drug delivery to the brain. Therefore, in this review, we summarize the potential role of different nutraceuticals in reducing HIV- and COVID-19-associated neurological complications and the use of EVs as nutraceutical/drug delivery vehicles to treat HIV, COVID-19, and other brain disorders.

Acute disseminated encephalomyelitis and COVID-19: A systematic synthesis of worldwide cases.

Acute disseminated encephalomyelitis (ADEM) has been reported after coronavirus disease 2019 (COVID-19). In this review, we systematically included worldwide reported cases on this association. We included 30 case reports (pediatric and adults) and explored epidemiological and clinical evidence. We described time to diagnosis, clinical, imaging, and laboratory features, response to treatment regimens, and differences regarding severity. Also, an original case report was presented. Neurologists must be alert to the occurrence of multifocal neurological symptoms with or without encephalopathy in patients recovered from COVID-19. Timely MRI studies should be performed to establish the diagnosis and to consider early corticosteroid-based treatment.

COVID-19 Pandemic and Neurological Disease: A Critical Review of the Existing Literature.

Most of what we know about the coronavirus disease 2019 (COVID-19) is limited to what we know about severe acute respiratory syndrome (SARS) and COVID-19's epidemiology, fatality, and acute care. However, infection with COVID-19 may also involve the central nervous system (CNS), which may or may not be due to a multi-organ injury. Our aim in this paper is to briefly summarize the main aspects of the growing literature on neurological manifestations of the COVID-19 infection. As such, after mentioning some general background on the economic and medical implications of the pandemic on individuals, the healthcare system, and the society, we summarize some common aspects of the published literature on neurological manifestations of the COVID-19 infection. We also highlight the existing gaps in the literature, which requires additional work. The most common neurological manifestation of COVID-19 infection is an olfactory deficit. However, it is still unknown if it is inflammatory or degenerative in nature. Still, the incidence of neurological complications, and also their mechanisms and treatments are unknown. This literature is predominantly composed of opinions and reviews rather than original articles, so the patients' data are not used for a majority of the studies. Multi-center studies that not only conduct chest CT or MRI but also brain CT or MRI are needed. Randomized trials are still required on the management of acute and chronic neurological conditions due to COVID-19 infection. Cohort studies may also determine the natural history of the conditions and factors that are prognostic. Furthermore, while disparities in COVID-19 infections are known, inequalities in neurological manifestations are unknown. Besides this, the efficacy of specific treatments on CNS involvement is still unknown. We will discuss the health care needs of patients with chronic neurological conditions. We Included a few recommendations for practice and further research at the end of this paper.

The involvement of the central nervous system in patients with COVID-19.

Coronaviruses disease (COVID-19) has caused major outbreaks. A novel variant, SARS-CoV-2, is responsible for COVID-19 pandemic. Clinical presentations and pathological mechanisms of COVID-19 are broad. The respiratory aspect of the disease has been extensively researched. Emerging studies point out the possibility of the central nervous system (CNS) involvement by COVID-19. Here, we discuss the current evidence for CNS involvement in COVID-19 and highlight that the high pathogenicity of SARS-CoV-2 might be due to its neuroinvasive potential.