Association of CNS demyelination and COVID-19 infection: an updated systematic review

Persistent alterations in gray matter in COVID-19 patients experiencing sleep disturbances: a 3-month longitudinal study

JOURNAL/nrgr/04.03/01300535-202510000-00030/figure1/v/2024-11-26T163120Z/r/image-tiff Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections. Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019 (COVID-19). However, neuroimaging studies on sleep disturbances caused by COVID-19 are scarce, and existing studies have primarily focused on the long-term effects of the virus, with minimal acute phase data. As a result, little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19. To address this issue, we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection, and verified the results using 3-month follow-up data. A total of 26 COVID-19 patients with sleep disturbances (aged 51.5 ± 13.57 years, 8 women and 18 men), 27 COVID-19 patients without sleep disturbances (aged 47.33 ± 15.98 years, 9 women and 18 men), and 31 age- and gender-matched healthy controls (aged 49.19 ± 17.51 years, 9 women and 22 men) were included in this study. Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis. We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes. The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores. Additionally, we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls. The 3-month follow-up data revealed indices of altered cerebral structure (cortical thickness, cortical grey matter volume, and cortical surface area) in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances. Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection. These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19.

MOG positive primary autoimmune meningitis mimicking tuberculous meningitis: a case series

Objectives

Primary autoimmune meningitis presentation of myelin oligodendrocyte glycoprotein (MOG) IgG antibody positivity is infrequently reported. We aim to identify the patients with MOG IgG antibody positivity who were initially misdiagnosed and treated as tuberculous meningitis (TBM).

Methods

A retrospective cross-sectional study conducted in the Neuroimmunology Laboratory and Department of Neurology of Amrita Institute of Medical Sciences, Kochi, Kerala, India between June 2018 and December 2023. MOG IgG antibody positive cases were identified from the Neuroimmunology Lab Registry, and the case sheets were screened for TBM-like presentation. Cases were included on the basis of MOG IgG positivity, an initial diagnosis of tuberculosis was suspected and antitubercular therapy was initiated with minimal response.

Results

We described the clinical, microbiological, radiological and serological features of five patients with a TBM-like presentation eventually diagnosed with MOG-associated meningitis. Symptoms included headache, vomiting, visual impairment and weakness. Three patients showed normal MRIs and two patients showed MRI findings consistent with demyelination. Serum MOG antibody testing was positive only on serial testing of all five patients. The final diagnosis was MOG-associated meningitis in two patients and MOG-associated meningoencephalitis in three patients.

Discussion

This case series highlights the rare presentation of MOG antibody positive patients presenting as primary autoimmune meningitis and its diagnostic challenges, especially in regions where tuberculosis is common. The study underscores the importance of considering autoimmune aetiology as a differential diagnosis when tuberculosis treatment fails or relapses occur, advocating for MOG IgG antibody testing to ensure accurate diagnosis and effective treatment.

Neurologic manifestations of COVID-19 and viral test in cerebrospinal fluid

BACKGROUND

Neurological manifestations are present in about one-third of COVID-19 cases, ranging from mild symptoms, such as anosmia, to more severe forms like demyelinating syndromes. Although direct invasion of the CNS has been demonstrated, the immune- mediated pathway is also described and more accepted. Even in cases where viral detection in CSF is absent, it should not rule out neuroinvasion. There are few prospective studies about neurological manifestations of COVID-19, especially with viral tests in CSF; as well there are still many questions about COVID-19 associated with neurological disease. Thus, we describe clinical and CSF findings of a prospective cohort of patients with nasal positive tests for SARS-CoV-2 and neurological involvement. We also discuss the pathogenic mechanisms related to these manifestations.

METHODS AND FINDINGS

This is a prospective cohort study; 27 patients were evaluated according to clinical presentation, the time interval between COVID-19 diagnosis and onset of neurological alterations, syndromic diagnosis, imaging and CSF findings. Real time polymerase chain reaction for SARS-CoV-2 genome was performed in all CSF samples. 2 RT-PCR in spinal cord fluid resulted positive in 9 (33.3%) cases, five of them had a positive swab nasal test concomitant to neurologic disease. Respiratory signs were described in 12 out 27 patients, five of them with viral detection in CSF. White cell counts in CSF were normal range in the majority of cases, except for 3 occurrences: two patients had elevated CSF WBC counts and viral detection in CSF (10 and 36 cells/mm3) and one also had elevated CSF WBC count but viral detection in CSF was negative (21cells/mm3). The observed neurological signs encompassed a diverse neurologic spectrum, including seizures, paresis, gait abnormalities, headaches, alteration in consciousness and memory or cognitive impairment. Both imaging and CSF alterations exhibited non-specific characteristics. Syndromic diagnoses included stroke, dementia or cognitive impairments, Guillain-Barré Syndrome, encephalitis, encephalomyelitis, acute flaccid palsy and optical neuritis.

CONCLUSIONS

The patients in the present study had COVID-19 and neurologic involvement including a wide range of clinical manifestations. SARS-CoV-2 was detected in one-third of CSF samples, regardless of time interval between COVID-19 diagnosis and the onset of neurological signs. These conditions encompass various pathogenic pathways and the neuroinvasion potential of SARS-CoV-2 should be more studied.

The vagus nerve-dependent lung-brain axis mediates brain demyelination following acute lung injury

Patients with acute lung injury (ALI) often experience psychiatric and neurological symptoms; however, the precise underlying mechanisms remain unclear. Given that white matter loss (demyelination) contributes to these symptoms, we investigated whether lipopolysaccharide (LPS)-induced ALI leads to brain demyelination via a vagus nerve-dependent lung-brain axis. A single intratracheal injection of LPS caused severe lung injury and demyelination in the corpus callosum (CC) of mouse brains. Subdiaphragmatic vagotomy did not affect LPS-induced lung injury or demyelination in the CC. Interestingly, cervical vagotomy significantly attenuated LPS-induced hypo-locomotion, plasma interleukin-6 levels, and demyelination in the CC of ALI mice without influencing lung injury. These findings demonstrate that ALI can induce demyelination in the CC of the mouse brain via a cervical vagus nerve-dependent lung-brain axis, highlighting the critical role of this pathway in the psychiatric and neurological symptoms observed in ALI patients.

Clinical characteristics of optic neuritis following COVID-19 during Omicron outbreak in China

PURPOSE

To investigate the clinical characteristics of early-onset optic neuritis (ON) following the corona virus disease 2019 (COVID-19) Omicron variant and explore the possible pathophysiological mechanisms.

METHODS

This was a retrospective, observational study. All enrolled patients with ON following the COVID-19 Omicron variant were followed for at least 6 weeks to observe their clinical characteristics and prognostic factors and to analyze the factors influencing earlier or later occurrence of ON following the COVID-19 Omicron variant.

RESULTS

A total of 47 eyes from 47 patients (22 males [46.8%] and 25 females [53.2%]) were enrolled in this study and divided into late- and early-onset groups. Compared to the late-onset group, the early-onset group had a higher dual-seronegative antibody status (21.43% vs. 63.16%, P = 0.004) and a higher CD8 + /lymphocyte percentage (23.3% [20.1%, 28.3%] vs. 31.0% [29.8%, 34.2%], P = 0.008). Furthermore, Pearson's partial correlation analysis showed that dual-seronegative antibody status (adjusted r = 0.800, adjusted P = 0.001) and CD8 + /lymphocyte percentage (adjusted r = 0.747, adjusted P = 0.002) were independently associated with early-onset ON following the COVID-19 Omicron variant. Further partial correlation analysis also showed that a swollen optic disc (r = -0.347, P = 0.035) was the only factor independently associated with final best-corrected visual acuity (BCVA).

CONCLUSIONS

Earlier onset of ON following COVID-19 Omicron variant indicated a higher CD8 + /lymphocyte percentage in the serum and a greater possibility of dual-seronegative antibody status. Whether ON following the COVID-19 Omicron variant occurred earlier or later did not independently affect final BCVA, and the only independent factor predicting better final BCVA was a swollen optic disc.

Neurological complications caused by SARS-CoV-2

SUMMARYSARS-CoV-2 can not only cause respiratory symptoms but also lead to neurological complications. Research has shown that more than 30% of SARS-CoV-2 patients present neurologic symptoms during COVID-19 (A. Pezzini and A. Padovani, Nat Rev Neurol 16:636-644, 2020, https://doi.org/10.1038/s41582-020-0398-3). Increasing evidence suggests that SARS-CoV-2 can invade both the central nervous system (CNS) (M.S. Xydakis, M.W. Albers, E.H. Holbrook, et al. Lancet Neurol 20: 753-761, 2021 https://doi.org/10.1016/S1474-4422(21)00182-4 ) and the peripheral nervous system (PNS) (M.N. Soares, M. Eggelbusch, E. Naddaf, et al. J Cachexia Sarcopenia Muscle 13:11-22, 2022, https://doi.org/10.1002/jcsm.12896), resulting in a variety of neurological disorders. This review summarized the CNS complications caused by SARS-CoV-2 infection, including encephalopathy, neurodegenerative diseases, and delirium. Additionally, some PNS disorders such as skeletal muscle damage and inflammation, anosmia, smell or taste impairment, myasthenia gravis, Guillain-Barré syndrome, ICU-acquired weakness, and post-acute sequelae of COVID-19 were described. Furthermore, the mechanisms underlying SARS-CoV-2-induced neurological disorders were also discussed, including entering the brain through retrograde neuronal or hematogenous routes, disrupting the normal function of the CNS through cytokine storms, inducing cerebral ischemia or hypoxia, thus leading to neurological complications. Moreover, an overview of long-COVID-19 symptoms is provided, along with some recommendations for care and therapeutic approaches of COVID-19 patients experiencing neurological complications.

SARS-CoV-2 infection and risk of subsequent demyelinating diseases: national register-based cohort study

Demyelinating diseases including multiple sclerosis are associated with prior infectious exposures, so we assessed whether SARS-CoV-2 infection is associated with subsequent diagnoses of non-multiple sclerosis demyelinating diseases and multiple sclerosis. All residents of Sweden aged 3-100 years were followed between 1 January 2020 and 30 November 2022, excluding those with demyelinating disease prior to 2020, comprising 9 959 818 individuals divided into uninfected and those who were infected were categorized into those with and without hospital admission for the infection as a marker of infection severity. Cox regression assessed the risk of two separate outcomes: hospital diagnosed non-multiple sclerosis demyelinating diseases of the CNS and multiple sclerosis. The exposures were modelled as time-varying covariates (uninfected, infection without hospital admission and infected with hospital admission). Hospital admission for COVID-19 was associated with raised risk of subsequent non-multiple sclerosis demyelinating disease, but only 12 individuals had this outcome among the exposed, and of those, 7 has an unspecified demyelinating disease diagnosis. Rates per 100 000 person-years (and 95% confidence intervals) were 3.8 (3.6-4.1) among those without a COVID-19 diagnosis and 9.0 (5.1-15.9) among those admitted to hospital for COVID-19, with an adjusted hazard ratio and (and 95% confidence interval) of 2.35 (1.32-4.18, P = 0.004). Equivalent associations with multiple sclerosis (28 individuals had this outcome among the exposed) were rates of 9.5 (9.1-9.9) and 21.0 (14.5-30.5) and an adjusted hazard ratio of 2.48 (1.70-3.61, P < 0.001). Only a small number of non-multiple sclerosis demyelinating disease diagnoses were associated with hospital admission for COVID-19, and while the number with multiple sclerosis was somewhat higher, longer duration of follow-up will assist in identifying whether the associations are causal or due to shared susceptibility or surveillance bias, as these diseases can have long asymptomatic and prodromal phases.

Neuropsychiatric Burden of SARS-CoV-2: A Review of Its Physiopathology, Underlying Mechanisms, and Management Strategies

The COVID-19 outbreak, caused by the SARS-CoV-2 virus, was linked to significant neurological and psychiatric manifestations. This review examines the physiopathological mechanisms underlying these neuropsychiatric outcomes and discusses current management strategies. Primarily a respiratory disease, COVID-19 frequently leads to neurological issues, including cephalalgia and migraines, loss of sensory perception, cerebrovascular accidents, and neurological impairment such as encephalopathy. Lasting neuropsychological effects have also been recorded in individuals following SARS-CoV-2 infection. These include anxiety, depression, and cognitive dysfunction, suggesting a lasting impact on mental health. The neuroinvasive potential of the virus, inflammatory responses, and the role of angiotensin-converting enzyme 2 (ACE2) in neuroinflammation are critical factors in neuropsychiatric COVID-19 manifestations. In addition, the review highlights the importance of monitoring biomarkers to assess Central Nervous System (CNS) involvement. Management strategies for these neuropsychiatric conditions include supportive therapy, antiepileptic drugs, antithrombotic therapy, and psychotropic drugs, emphasizing the need for a multidisciplinary approach. Understanding the long-term neuropsychiatric implications of COVID-19 is essential for developing effective treatment protocols and improving patient outcomes.

Suspected intracranial hypertension in COVID-19 patients with severe respiratory failure

BACKGROUND

COVID-19 patients may exhibit neurological symptoms due to direct viral damage, systemic inflammatory syndrome, or treatment side effects. Mechanical ventilation in patients with severe respiratory failure often requires sedation and neuromuscular blockade, hindering thorough clinical examinations. This study aimed to investigate neurological involvement through clinical and noninvasive techniques and to detect signs of intracranial hypertension in these patients.

METHOD

We conducted a prospective observational study on mechanically ventilated COVID-19 adult patients admitted to our ICU, following standard of care protocols for ventilation and permissive hypercapnia. Data were collected at three time points: admission day (T1), day seven (T7), and day fourteen (T14). At each time point, patients underwent multimodal noninvasive neurological monitoring, including clinical examination, pupillary reactivity, transcranial color doppler of the middle cerebral artery (MCA), and optic nerve sheath diameter (ONSD) assessed via ultrasound (US). Head computer tomography (CT) was performed at T1 and T14. A limited subset of patients had a follow-up examination six months after ICU discharge.

RESULTS

Seventy-nine patients were recruited; most were under deep sedation and neuromuscular blockade at T1. Pupillary size, symmetry, and reactivity were normal, as was the MCA mean velocity. However, ONSD, assessed by both US and CT, appeared enlarged, suggesting raised intracranial pressure (ICP). In a subgroup of 12 patients, increased minute ventilation was associated with a significant decrease in US-ONSD, corresponding to a drop in paCO2. At follow-up, twelve patients showed no long-term neurological sequelae, and US-ONSD was decreased in all of them.

DISCUSSION AND CONCLUSIONS

In this cohort, enlarged ONSD was detected during non-invasive neurological monitoring, suggesting a raised ICP, with hypercapnia playing a prominent role. Further studies are needed to explore ONSD behavior in other samples of mechanically ventilated, hypercapnic patients.

Case report: Concurrent MOG antibody-associated disease and latent infections in two patients

Objectives

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is frequently preceded by infections. The underlying pathomechanism, however, remains poorly understood. Here, we present the clinical data of two MOGAD patients with concurrent syphilis infection and investigate the reactivity of patient-derived antibodies to MOG and Treponema pallidum (T. pallidum).

Methods

Longitudinal serum samples and soluble immunoglobulins in single B cell supernatants were measured for MOG reactivity by a live cell-based assay. Reactivity against T. pallidum was assessed by enzyme-linked immunosorbent assay.

Results

The two patients presented MOGAD and concurrent latent syphilis infection, manifesting as cervical myelitis and unilateral optic neuritis, respectively. The first patient had been living with HIV on antiretroviral therapy, and the second was concomitantly diagnosed with chronic hepatitis B infection. Upon screening of B cell supernatants, we identified reactivity to MOG or T. pallidum. Notably, one B cell showed reactivity to both antigens.

Discussion

The coexistence of MOGAD diagnoses and latent syphilis, alongside the identification of antibody reactivity to MOG and T. pallidum, underscores the potential pathomechanistic link between syphilis infection and subsequent autoimmune neuroinflammation. Cross-reactivity between MOG and T. pallidum antibodies remains to be validated on a molecular level, and further characterization of infectious triggers associated with MOGAD is needed.

Ocular manifestations of COVID-19

There is an increasing body of knowledge regarding how COVID-19 may be associated with ocular disease of varying severity and duration. This article discusses the literature on the ocular manifestations associated with COVID-19, including appraisal of the current evidence, suggested mechanisms of action, associated comorbidities and risk factors, timing from initial infection to diagnosis and clinical red flags. The current literature primarily comprises case reports and case series which inevitably lack control groups and evidence to support causality. However, these early data have prompted the development of larger population-based and laboratory studies that are emerging. As new data become available, a better appraisal of the true effects of COVID-19 on the eye will be possible. While the COVID-19 pandemic was officially declared no longer a "global health emergency" by the World Health Organization (WHO) in May 2023, case numbers continue to rise. Reinfection with different variants is predicted to lead to a growing cumulative burden of disease, particularly as more chronic, multi-organ sequelae become apparent with potentially significant ocular implications. COVID-19 ocular manifestations are postulated to be due to three main mechanisms: firstly, there is a dysregulated immune response to the initial infection linked to inflammatory eye disease; secondly, patients with COVID-19 have a greater tendency towards a hypercoagulable state, leading to prothrombotic events; thirdly, patients with severe COVID-19 requiring hospitalisation and are immunosuppressed due to administered corticosteroids or comorbidities such as diabetes mellitus are at an increased risk of secondary infections, including endophthalmitis and rhino-orbital-mucormycosis. Reported ophthalmic associations with COVID-19, therefore, include a range of conditions such as conjunctivitis, scleritis, uveitis, endogenous endophthalmitis, corneal graft rejection, retinal artery and vein occlusion, non-arteritic ischaemic optic neuropathy, glaucoma, neurological and orbital sequelae. With the need to consider telemedicine consultation in view of COVID-19's infectivity, understanding the range of ocular conditions that may present during or following infection is essential to ensure patients are appropriately triaged, with prompt in-person ocular examination for management of potentially sight-threatening and life-threatening diseases.

Demyelination in Patients with POST-COVID Depression

Background: Depression is one of the most severe sequelae of COVID-19, with major depressive disorder often characterized by disruption in white matter (WM) connectivity stemming from changes in brain myelination. This study aimed to quantitatively assess brain myelination in clinically diagnosed post-COVID depression (PCD) using the recently proposed MRI method, macromolecular proton fraction (MPF) mapping. Methods: The study involved 63 recovered COVID-19 patients (52 mild, 11 moderate, and 2 severe) at 13.5 ± 10.0 months post-recovery, with matched controls without prior COVID-19 history (n = 19). A post-COVID depression group (PCD, n = 25) was identified based on psychiatric diagnosis, while a comparison group (noPCD, n = 38) included participants with neurological COVID-19 complications, excluding clinical depression. Results: Fast MPF mapping revealed extensive demyelination in PCD patients, particularly in juxtacortical WM (predominantly occipital lobe and medial surface), WM tracts (inferior fronto-occipital fasciculus (IFOF), posterior thalamic radiation, external capsule, sagittal stratum, tapetum), and grey matter (GM) structures (hippocampus, putamen, globus pallidus, and amygdala). The noPCD group also displayed notable demyelination, but with less magnitude and propagation. Multiple regression analysis highlighted IFOF demyelination as the primary predictor of Hamilton scores, PCD presence, and severity. The number of post-COVID symptoms was a significant predictor of PCD presence, while the number of acute symptoms was a significant predictor of PCD severity. Conclusions: This study, for the first time, reveals extensive demyelination in numerous WM and GM structures in PCD, outlining IFOF demyelination as a key biomarker.

Fifteen acute retrobulbar optic neuritis associated with COVID-19: A case report and review of literature

BACKGROUND

A subtype of the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is suggested to be responsible for the outbreak in Northern China since the quarantine was lifted in December 2022. The coronavirus disease 2019 virus is primarily responsible for the development of respiratory illnesses, however, it can present a plethora of symptoms affecting a myriad of body organs. This virus has been theorized to be linked to demyelinating lesions of the peripheral and central nervous system including transverse myelitis and acute retrobulbar optic neuritis (ARON). For example, magnetic resonance imaging (MRI) of the orbit and brain showed enlargement of the retrobulbar intraorbital segments of the optic nerve with high T2 signal, and no abnormalities were seen in the brain tissue. In this case series, we analyzed the connection between SARS-CoV-2 infection and the onset of ARON.

CASE SUMMARY

Fifteen patients, and a teenage boy who did not have any pre-existing ocular or demyelinating diseases suddenly experienced a loss of vision after SARS-CoV-2 infection. The patients expressed a central scotoma and a fever as the primary concern. The results of the fundus photography were found to be normal. However, the automated perimetry and MRI scans showed evidence of some typical signs. Out of the 15 patients diagnosed with ARON after SARS-CoV-2 infection, only one individual tested positive for the aquaporin-4 antibody.

CONCLUSION

Direct viral invasion of the central nervous system and an immune-related process are the two primary causes of SARS-CoV-2-related ARON.

COVID-19: Unveiling the Neuropsychiatric Maze-From Acute to Long-Term Manifestations

The SARS-CoV-2 virus has spread rapidly despite implementing strategies to reduce its transmission. The disease caused by this virus has been associated with a diverse range of symptoms, including common neurological manifestations such as dysgeusia, anosmia, and myalgias. Additionally, numerous cases of severe neurological complications associated with this disease have been reported, including encephalitis, stroke, seizures, and Guillain-Barré syndrome, among others. Given the high prevalence of neurological manifestations in this disease, the objective of this review is to analyze the mechanisms by which this virus can affect the nervous system, from its direct invasion to aberrant activation of the immune system and other mechanisms involved in the symptoms, including neuropsychiatric manifestations, to gain a better understanding of the disease and thus facilitate the search for effective therapeutic strategies.

The Neurological Implications of COVID-19: A Comprehensive Narrative Review

The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 revealed a huge number of problems as well as discoveries in medicine, notably, regarding the effects of the virus on the central nervous system (CNS) and peripheral nervous system (PNS). This paper is a narrative review that takes a deep dive into the complex interactions between COVID-19 and the NS. Therefore, this paper explains the broad range of neurological manifestations and neurodegenerative diseases caused by the virus. It carefully considers the routes through which SARS-CoV-2 reaches the NS, including the olfactory system and of course, the hematogenous route, which are also covered when discussing the virus's direct and indirect mechanisms of neuropathogenesis. Besides neurological pathologies such as stroke, encephalitis, Guillain-Barré syndrome, Parkinson's disease, and multiple sclerosis, the focus area is also given to the challenges of making diagnosis, treatment, and management of these conditions during the pandemic. The review also examines the strategic and interventional approaches utilized to prevent these disorders, as well as the ACE2 receptors implicated in the mediation of neurological effects caused by COVID-19. This detailed overview, which combines research outputs with case data, is directed at tackling this pandemic challenge, with a view toward better patient care and outcomes in the future.

Bilateral optic neuritis and encephalopathy as the atypical presentations of multiple sclerosis following severe acute respiratory syndrome coronavirus 2 infection

Numerous evidence suggests coronavirus disease 2019 (COVID-19) potentially triggers demyelinating diseases, inclusive of multiple sclerosis (MS), and acute disseminated encephalomyelitis (ADEM), and various mechanisms have been proposed. We report a 42-year-old male presented with bilateral optic neuritis and encephalopathy, 2 weeks following COVID-19 infection. He denied any history or family history of neurological and ocular diseases. Severe bilateral visual impairment (only light perception) and pain with eye movement were reported. Fundoscopy revealed bilateral optic disc swelling. Magnetic resonance imaging showed tortuous bilateral optic nerves with optic nerve and nerve sheath enhancement. Multiple hyperintense nodules in bilateral cerebral white matter were noted on fluid-attenuated inversion recovery T2-weighted imaging without diffusion restriction or gadolinium contrast enhancement. Hypointense nodules in cerebral white matter were also noted on T1-weighted imaging, which implied some old lesions. Dissemination in space and time and cerebrospinal fluid-specific oligoclonal bands confirmed the diagnosis of MS. Both serum aquaporin-4 and myelin oligodendrocyte glycoprotein antibodies were negative. He received pulse steroid therapy for 5 days, followed by slowly tapering oral prednisolone. His vision, ocular motion pain, and encephalopathy improved gradually. However, the visual outcome was still poor (bilateral 20/400), and optic atrophy was noticed during 1-year follow-up. To our knowledge, this is the first case of MS following severe acute respiratory syndrome coronavirus 2 infection presented with bilateral optic neuritis and encephalopathy. Since these manifestations are exceedingly rare in MS, we suspect acute immune reactions induced by COVID-19 could bring about the atypical ADEM-like presentations of MS.

Predicting factors for acute encephalopathy in febrile seizure children with SARS-CoV-2 omicron variant: a retrospective study

BACKGROUND

SARS-CoV-2 posed a threat to children during the early phase of Omicron wave because many patients presented with febrile seizures. The study aimed to investigate predicting factors for acute encephalopathy of children infected by SARS-CoV-2 Omicron variant presenting with febrile seizures.

METHODS

The retrospective study analyzed data from pediatric patients who visited the emergency department of Chang Gung Memorial Hospital in Taiwan between April and July 2022. We specifically focused on children with COVID-19 who presented with febrile seizures, collecting demographic, clinical, and laboratory data at the pediatric emergency department, as well as final discharge diagnoses. Subsequently, we conducted a comparative analysis of the clinical and laboratory characteristics between patients diagnosed with acute encephalopathy and those with other causes of febrile seizures.

RESULTS

Overall, 10,878 children were included, of which 260 patients presented with febrile seizures. Among them, 116 individuals tested positive for SARS-CoV-2 and of them, 14 subsequently developed acute encephalopathy (12%). Those with acute encephalopathy displayed distinctive features, including older age (5.1 vs. 2.6 years old), longer fever duration preceding the first seizure (1.6 vs. 0.9 days), cluster seizure (50% vs. 16.7%), status epilepticus (50% vs. 13.7%) and occurrences of bradycardia (26.8% vs. 0%) and hypotension (14.3% vs. 0%) in the encephalopathy group. Besides, the laboratory findings in the encephalopathy group are characterized by hyperglycemia (mean (95% CI) 146 mg/dL (95% CI 109-157) vs. 108 mg/dL (95% CI 103-114) and metabolic acidosis (mean (95% CI) pH 7.29(95% CI 7.22-7.36) vs. 7.39 (95%CI 7.37-7.41)).

CONCLUSIONS

In pediatric patients with COVID-19-related febrile seizures, the occurrence of seizures beyond the first day of fever, bradycardia, clustered seizures, status epilepticus, hyperglycemia, and metabolic acidosis should raise concerns about acute encephalitis/encephalopathy. However, the highest body temperature and the severity of leukocytosis or C-reactive protein levels were not associated with poor outcomes.

Infectious Myelopathies

OBJECTIVE

Infectious myelopathy of any stage and etiology carries the potential for significant morbidity and mortality. This article details the clinical presentation, risk factors, and key diagnostic components of infectious myelopathies with the goal of improving the recognition of these disorders and guiding subsequent management.

LATEST DEVELOPMENTS

Despite our era of advanced multimodal imaging and laboratory diagnostic technology, a causative organism often remains unidentified in suspected infectious and parainfectious myelopathy cases. To improve diagnostic capability, newer technologies such as metagenomics are being harnessed to develop diagnostic assays with a greater breadth of data from each specimen and improvements in infection identification. Conventional assays have been optimized for improved sensitivity and specificity.

ESSENTIAL POINTS

Prompt recognition and treatment of infectious myelopathy decreases morbidity and mortality. The key diagnostic tools include serologies, CSF analysis, and imaging; however clinical presentation, epidemiologic risk factors, and history of recent illness are all vital to making the proper diagnosis because current laboratory and imaging modalities are often inconclusive. The cornerstone of recommended treatment is targeted antimicrobials with appropriate immune modulation, surgical intervention, supportive care, and interdisciplinary involvement, all of which further improve outcomes for patients with infectious myelopathy.

Treatment refractory acute necrotizing myelitis after COVID-19 vaccine injection: a case report

Introduction and importance

Post-vaccination myelitis is a rare and debilitating clinical situation. There are few reports of post-COVID-19 infection and vaccination neurological sequela.

Case presentation

A 69-year-old lady was admitted to the emergency department due to weakness and hypoesthesia in her hands 1 week after the Sinopharm vaccine injection. MRI showed a cervicothoracic cord haemorrhagic lesion that deteriorated within 48 h. The clinical course was refractory to conservative treatments. She underwent an emergency cervical laminectomy as a salvage treatment. Intraoperative samples were in favour of acute necrotizing myelitis.

Discussion

In the review of the literature, the inflammatory storm, vasculitis, and many unknown etiologies are deemed to be the possible causes of encephalopathy and myelitis after COVID-19 infection and vaccination. There are few cases of post-COVID-19 myelitis and hematomyelia, but this case was the first report of post-vaccination necrotizing myelitis.

Conclusion

Post-vaccination necrotizing myelitis is a lethal medical situation requiring intensive and emergent neurosurgical vigilance. Early clinical diagnosis in the beginning and full neurosurgical-neurological treatment armamentarium options are cornerstones of treatment paradigms. Salvage treatment options such as extensive laminectomy may play a life-saving role in treatment refractory cases of acute necrotizing myelitis.

Optic Neuritis and Cranial Neuropathies Diagnosis Rates before Coronavirus Disease 2019, in the Initial Pandemic Phase, and Post-Vaccine Introduction

PURPOSE

To compare rates of diagnosis of neuro-ophthalmic conditions across the Coronavirus Disease 2019 (COVID-19) pandemic with pre-pandemic levels.

DESIGN

Multicenter, retrospective, observational study.

PARTICIPANTS

Patients seen for eye care between March 11, 2019, and December 31, 2021.

METHODS

A multicenter electronic health record database, Sight Outcomes Research Collaborative (SOURCE), was queried for new diagnoses of neuro-ophthalmic conditions (cranial nerve [CN] III, IV, VI, and VII palsy; diplopia; and optic neuritis) and new diagnoses of other ophthalmic conditions from January 1, 2016, to December 31, 2021. Data were divided into 3 periods (pre-COVID, pre-COVID vaccine, and after introduction of COVID vaccine), with a 3-year look-back period. Logistic regressions were used to compare diagnosis rates across periods. Two-sample z-test was used to compare the log odds ratio (OR) of the diagnosis in each period with emergent ocular conditions: retinal detachment (RD) and acute angle-closure glaucoma (AACG).

MAIN OUTCOME MEASURES

Diagnosis rate of neuro-ophthalmic conditions in each study period.

RESULTS

A total of 323 261 unique patients (median age 59 years [interquartile range, 43-70], 58% female, 68% White) across 5 academic centers were included, with 180 009 patients seen in the pre-COVID period, 149 835 patients seen in the pre-COVID vaccine period, and 164 778 patients seen in the COVID vaccine period. Diagnosis rates of CN VII palsy, diplopia, glaucoma, and cataract decreased from the pre-COVID period to the pre-vaccine period. However, the optic neuritis diagnoses increased, in contrast to a decrease in RD diagnoses (P = 0.021). By comparing the diagnosis rates before and after widespread vaccination, all eye conditions evaluated were diagnosed at higher rates in the COVID vaccination period compared with pre-COVID and pre-vaccine periods. The log OR of neuro-ophthalmic diagnosis rates across every period comparison were largely similar to emergency conditions (RD and AACG, P > 0.05). However, the log OR of cataract and glaucoma diagnoses were different to RD or AACG (P < 0.05) in each period comparison.

CONCLUSIONS

Neuro-ophthalmic diagnoses had a similar reduction in diagnosis rates as emergent eye conditions in the first part of the pandemic, except optic neuritis. After widespread COVID-19 vaccination, all ophthalmic diagnosis rates increased compared with pre-pandemic rates, and the increase in neuro-ophthalmic diagnosis rates did not exceed the increase in RD and AACG diagnosis rates.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Pediatric neuroimaging findings and clinical presentations of COVID-19: A systematic review

OBJECTIVES

Symptoms from SARS-CoV-2 infection can involve multiple organ systems. Several reviews discussed the neurologic involvement and neuroimaging findings in adults but research on children is lacking. This study aimed to analyze the incidence of neurologic involvement in patients diagnosed with pediatric inflammatory multisystem syndrome temporally associated with COVID-19 (PIMS-TS) or multisystem inflammatory syndrome in children (MIS-C); and also to summarize current literature on possible neuroimaging findings in SARS-CoV-2 infected children.

METHODS

A literature search in six electronic databases was performed to retrieve case series, cohort studies, and cross-sectional studies on neurologic involvement in COVID-19 patients younger than 21 years of age published between December 2019 to September 2023, including COVID-19 patients.

RESULTS

A total of 2224 patients with MIS-C from 10 cohorts and cross-sectional studies suggested that neurologic involvement in these subsets ranges from 8.5% to 32.1%. Symptoms included acute encephalitis, seizures, stroke, cranial nerve palsy, nausea/vomiting, and intracranial hypertension. Neuroradiology findings of 114 children from 50 case reports included splenial or acute disseminated encephalomyelitis (ADEM)-like lesions, cytotoxic brain edema, autoimmune demyelinating diseases, ischemic stroke and arteritis, venous thrombosis, intracranial hemorrhage, meningitis, posterior reversible encephalopathy syndrome, anti-N-methyl-D-aspartate receptor autoimmune encephalitis, acute hemorrhagic leukoencephalitis, hydrocephalus, olfactory bulb atrophy, cerebellitis, and acute necrotizing encephalitis.

CONCLUSION

Radiologic findings of SARS-CoV-2 infection in the pediatric population are diverse. Neuroimaging studies should be considered in critically ill patients to rule out neurologic involvement and facilitate early interventions.

The effect of COVID-19 on Multiple Sclerosis relapse: A systematic review and meta-analysis

BACKGROUND

Multiple Sclerosis (MS) is a chronic autoimmune disease, affecting over 2.5 million people worldwide. There has been growing concern about the impact of COVID-19 on the clinical course of MS. However, these findings remain controversial, and there is a lack of high-quality evidence to establish the relationship between COVID-19 and MS.

METHODS

A comprehensive search was done to identify relevant studies reporting relapse rate in patients with MS (pwMS), those comparing the relapse rate of COVID-19 pwMS and MS controls, and studies investigating the effect of COVID-19 on relapse rate of pwMS. The results were presented as proportion of COVID-19 pwMS experiencing relapse and odds ratio determining the impact of COVID-19 on relapse rate.

RESULTS

Fourteen studies were included in the analyses. The proportion of COVID-19 positive pwMS with relapse was 7.71 per 100 cases (95 % confidence interval, CI: 4.41-13.89, I2=96 %). Quantitative evaluation of studies with pwMS without COVID-19 did not demonstrate a statistically significant difference in relapse rate of patients with COVID-19 (OR: 0.75, 95 %CI: 0.44-1.29, I2= 54 %). Subgroup and sensitivity analyses did not alter the lack of significance of association between COVID-19 and MS relapse. Sensitivity analysis excluding the outlying study was largely in favor of no difference between the groups (OR:1.00, 95 %CI: 0.72-1.38, I2=34 %) CONCLUSION: The results of this review does not suggest that COVID-19 influences the relapse rate in pwMS. While the findings alleviate the concerns regarding the co-occurrence of the diseases, further studies are needed to investigate the effects of confounding factors.

Spontaneous spinal epidural haematoma following COVID-19 vaccination: a case report

Introduction

COVID-19 vaccination side effects are rare but important medical situations. Spine-affecting side effects are amongst the rarest, but exceedingly important. Haemorrhagic spinal manifestations of COVID-19 and its vaccines are less reported with little knowledge about them.

Case presentation

An 80-year-old male who received his first shot of the COVID-19 vaccine had developed COVID-19 pneumonia, weakness, and sensory problems in his legs followed by sphincter incontinence within 5 days period. MRI showed a spontaneous epidural spinal epidural haematoma (SSEDH) in T10-L1. He underwent laminectomy and haematoma evacuation. One month follow-up showed no clinical improvement.

Discussion

To our knowledge, this was the first post-vaccination SSEDH and second in haemorrhagic spinal complications following COVID-19 vaccination. Considering the neuropathogenesis pathway of COVID-19 and its vaccines, there are common mechanisms of action that could potentially justify post-vaccination SSEDH such as seen in COVID-19 infection, itself. Early Neurosurgical intervention and better preoperative neurological status could be a beneficial modifier for favourable clinical outcomes.

Conclusion

SSEDH and COVID-19 vaccine coincidence is a rare clinical event, still no solid association could be scientifically explained. Further studies are required for a reliable pathophysiologic association. Early diagnosis, interdisciplinary medical approach, and faster intervention are the cornerstone of the treatment paradigm.

Causal relationships between susceptibility and severity of COVID-19 and neuromyelitis optica spectrum disorder (NMOSD) in European population: a bidirectional Mendelian randomized study

Background

Neurological disorders can be caused by viral infections. The association between viral infections and neuromyelitis optica spectrum disorder (NMOSD) has been well-documented for a long time, and this connection has recently come to attention with the occurrence of SARS-CoV-2 infection. However, the precise nature of the causal connection between NMOSD and COVID-19 infection remains uncertain.

Methods

To investigate the causal relationship between COVID-19 and NMOSD, we utilized a two-sample Mendelian randomization (MR) approach. This analysis was based on the most extensive and recent genome-wide association study (GWAS) that included SARS-CoV-2 infection data (122616 cases and 2475240 controls), hospitalized COVID-19 data (32519 cases and 2062805 controls), and data on severe respiratory confirmed COVID-19 cases (13769 cases and 1072442 controls). Additionally, we incorporated a GWAS meta-analysis comprising 132 cases of AQP4-IgG-seropositive NMOSD (NMO-IgG+), 83 cases of AQP4-IgG-seronegative NMOSD (NMO-IgG-), and 1244 controls.

Results

The findings of our study indicate that the risk of developing NMO-IgG+ is elevated when there is a genetic predisposition to SARS-CoV-2 infection (OR = 5.512, 95% CI = 1.403-21.657, P = 0.014). Furthermore, patients with genetically predicted NMOSD did not exhibit any heightened susceptibility to SARS-CoV2 infection, COVID-19 hospitalization, or severity.

Conclusion

our study using Mendelian randomization (MR) revealed, for the first time, that the presence of genetically predicted SARS-CoV2 infection was identified as a contributing factor for NMO-IgG+ relapses.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease and COVID-19: A Systematic Review

Background

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an uncommon neurological disease affecting the central nervous system (CNS). Numerous neurological disorders, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), acute transverse myelitis (ATM), and MOGAD, have been reported following the COVID-19 infection during the current COVID-19 pandemic. On the other hand, it has been suggested that patients with MOGAD may be at greater risk for infection (particularly in the current pandemic).

Objective

In this systematic review, we gathered separately 1) MOGAD cases following COVID-19 infection as well as 2) clinical course of patients with MOGAD infected with COVID-19 based on case reports/series.

Methods

329 articles were collected from 4 databases. These articles were conducted from inception to March 1st, 2022.

Results

Following the screening, exclusion criteria were followed and eventually, 22 studies were included. In 18 studies, a mean ± SD time interval of 18.6 ± 14.9 days was observed between infection with COVID-19 and the onset of MOGAD symptoms. Symptoms were partially or completely recovered in a mean of 67 days of follow-up. Among 4 studies on MOGAD patients, the hospitalization rate was 25%, and 15% of patients were hospitalized in the intensive care unit (ICU).

Conclusion

Our systematic review demonstrated that following COVID-19 infection, there is a rare possibility of contracting MOGAD. Moreover, there is no clear consensus on the susceptibility of MOGAD patients to severe COVID-19. However, obtaining deterministic results requires studies with a larger sample size.

Causal associations between prodromal infection and neuromyelitis optica spectrum disorder: A Mendelian randomization study

BACKGROUND AND PURPOSE

Prodromal infections are associated with neuromyelitis optica spectrum disorder (NMOSD), but it remains unclear which type of infection has a causal association with NMOSD. We aimed to explore the causal associations between four herpesvirus infections (chickenpox, cold sores, mononucleosis and shingles) and NMOSD, as well as between other types of infections and NMOSD.

METHODS

For data on infections, we used the genome-wide association study (GWAS) summary statistics from the 23andMe cohort. For outcomes, we used the GWAS data of participants of European ancestry, including 215 NMOSD patients (132 anti-aquaporin-4 antibody [AQP4-ab]-positive patients and 83 AQP4-ab-negative patients) and 1244 normal controls. Single-nucleotide polymorphism (SNP) identification and two-sample Mendelian randomization (MR) analyses were then performed.

RESULTS

In the 23andMe cohort, we identified one SNP for chickenpox (rs9266089 in HLA-B gene), one SNP for cold scores (rs885950 in the POU5F1 gene), one SNP for mononucleosis (rs2596465 in the HCP5 gene), and three SNPs for shingles (rs2523591 in the HLA-B gene; rs7047299 in the IFNA21 gene; rs9260809 in the MICD gene). The association between cold sores and AQP4-ab-positive NMOSD reached statistical significance (odds ratio [OR] 745.318; 95% confidence interval [CI] 22.176, 25,049.53 [p < 0.001, Q < 0.001]). The association between shingles and AQP4-ab-positive NMOSD was also statistically significant (OR 21.073; 95% CI 4.271, 103.974 [p < 0.001, Q < 0.001]). No significant association was observed between other infections and AQP4-ab-positive or AQP4-ab-negative NMOSD.

CONCLUSION

These findings suggest there are positive associations between cold sores and shingles and AQP4-ab-positive NMOSD, indicating there may be causal links between herpes simplex virus and varicella-zoster virus infection and AQP4-ab-positive NMOSD.

Relationship Between Clinical Outcomes and Nerve Conduction Studies Before and After Viral Infections in Healthy Individuals: Case Series

BACKGROUND

The neurological effect of viral respiratory infections has been acknowledged in many studies. However, patients who recovered from this infection show neurological manifestations and are not being routinely transferred for electrodiagnostic evaluation.

AIM

This study aimed to examine the neurological effect of viral respiratory infections on the nerve function using electrophysiology in patients fully recovered from viral respiratory infections.

METHODS

To limit bias in the results, the authors decided to choose patients who recovered from one virus in all participants (coronavirus). Medical records were screened for patients who performed nerve conduction studies (NCSs) before the coronavirus pandemic. Thirty patients met our inclusion criteria, and only 10 showed up to perform NCS. Data of the NCS was compared before and after the coronavirus infection for motor and sensory NCS parameters.

RESULTS

An increase in both the median and ulnar sensory nerve latencies and a decrease in the sensory nerve amplitude was observed. Also, there was a decrease in the motor conduction velocity (MCV) of the ulnar nerves and motor amplitude in the median nerve. In the lower limbs, there was a decrease in the sural nerve latency, increased MCV in the tibial nerves, and decreased MCV in the peroneal nerves. The proximal amplitudes of the tibial and peroneal nerves were increased, but the distal amplitude was increased only in the peroneal nerves and decreased in the tibial nerves.

CONCLUSION

There is a significant impact of viral infections on the peripheral nerves. Large-scale prospective studies are required to investigate the pathogenesis of the neuropathy and myopathy after viral infections.

Post-COVID-19 Demyelinating Disease and Its Effect on the Lower Urinary Tract: A Rare Case of a 14-Year-Old Man

The COVID-19 pandemic caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) has led to a wide range of manifestations, including urological issues. Patients with COVID-19 frequently experience complications, such as acute kidney injury (AKI) and thromboembolism. Neurological problems, including demyelination in the central and peripheral nervous systems, have also been reported in COVID-19 cases. This neurological damage can be attributed to the virus's neurotropic and neuro-invasive properties. This case study presents a 14-year-old patient who developed severe lower urinary tract symptoms following a COVID-19 infection, leading to a demyelinating disease affecting the lower urinary tract. The patient was managed successfully with specialized neuro-urological care, highlighting the importance of multidisciplinary collaboration in managing post-COVID-19 complications. Clinicians need to be vigilant about potential neurological manifestations in COVID-19 patients, including those affecting the urinary system, and patients should seek specialized medical attention for persistent symptoms.

MRI with generalized diffusion encoding reveals damaged white matter in patients previously hospitalized for COVID-19 and with persisting symptoms at follow-up

There is mounting evidence of the long-term effects of COVID-19 on the central nervous system, with patients experiencing diverse symptoms, often suggesting brain involvement. Conventional brain MRI of these patients shows unspecific patterns, with no clear connection of the symptomatology to brain tissue abnormalities, whereas diffusion tensor studies and volumetric analyses detect measurable changes in the brain after COVID-19. Diffusion MRI exploits the random motion of water molecules to achieve unique sensitivity to structures at the microscopic level, and new sequences employing generalized diffusion encoding provide structural information which are sensitive to intravoxel features. In this observational study, a total of 32 persons were investigated: 16 patients previously hospitalized for COVID-19 with persisting symptoms of post-COVID condition (mean age 60 years: range 41-79, all male) at 7-month follow-up and 16 matched controls, not previously hospitalized for COVID-19, with no post-COVID symptoms (mean age 58 years, range 46-69, 11 males). Standard MRI and generalized diffusion encoding MRI were employed to examine the brain white matter of the subjects. To detect possible group differences, several tissue microstructure descriptors obtainable with the employed diffusion sequence, the fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity, microscopic anisotropy, orientational coherence (Cc) and variance in compartment's size (CMD) were analysed using the tract-based spatial statistics framework. The tract-based spatial statistics analysis showed widespread statistically significant differences (P < 0.05, corrected for multiple comparisons using the familywise error rate) in all the considered metrics in the white matter of the patients compared to the controls. Fractional anisotropy, microscopic anisotropy and Cc were lower in the patient group, while axial diffusivity, radial diffusivity, mean diffusivity and CMD were higher. Significant changes in fractional anisotropy, microscopic anisotropy and CMD affected approximately half of the analysed white matter voxels located across all brain lobes, while changes in Cc were mainly found in the occipital parts of the brain. Given the predominant alteration in microscopic anisotropy compared to Cc, the observed changes in diffusion anisotropy are mostly due to loss of local anisotropy, possibly connected to axonal damage, rather than white matter fibre coherence disruption. The increase in radial diffusivity is indicative of demyelination, while the changes in mean diffusivity and CMD are compatible with vasogenic oedema. In summary, these widespread alterations of white matter microstructure are indicative of vasogenic oedema, demyelination and axonal damage. These changes might be a contributing factor to the diversity of central nervous system symptoms that many patients experience after COVID-19.

Parainfectious Brown-Séquard syndrome associated with COVID-19

Acute myelitis encompasses syndromes associated with inflammation of the spinal cord. In cases of inflammatory lesions that only involve a unilateral portion of the axial plane of the cord, Brown-Séquard syndrome may occur, resulting in potential ipsilateral corticospinal, dorsal spinocerebellar, or dorsal column dysfunction or contralateral spinothalamic dysfunction below the level of the lesion. We report a case of an adult male who presented with Brown-Séquard syndrome and with a positive SARS-CoV-2 nasopharyngeal swab PCR test. Neurological symptoms rapidly resolved after initiation of high-dose methylprednisolone. The findings reported not only contribute to documenting a new presentation of neurological complications associated with SARS-CoV-2 infection but also non-exclusively supports the body of literature suggesting the immune-mediated response to this infection as a mechanism of neuropathogenesis. In this case, COVID-19-related acute myelitis responded to treatment with a short regimen of high-dose glucocorticoids.

SARS-CoV-2 antibodies in inflammatory neurological conditions: a multicentre retrospective comparative study

It is well established that neurological and non-neurological autoimmune disorders can be triggered by viral infections. It remains unclear whether SARS-CoV-2 infection induces similar conditions and whether they show a distinctive phenotype. We retrospectively identified patients with acute inflammatory CNS conditions referred to our laboratory for antibody testing during the pandemic (March 1 to August 31, 2020). We screened SARS-COV-2 IgA/IgG in all sera by ELISA and confirmed the positivity with additional assays. Clinical and paraclinical data of SARS-COV-2-IgG seropositive patients were compared to those of seronegative cases matched for clinical phenotype, geographical zone, and timeframe. SARS-CoV-2-IgG positivity was detected in 16/339 (4%) sera, with paired CSF positivity in 3/16. 5 of these patients had atypical demyelinating disorders and 11 autoimmune encephalitis syndromes. 9/16 patients had a previous history of SARS-CoV-2 infection and 6 of them were symptomatic. In comparison with 32 consecutive seronegative controls, SARS-CoV-2-IgG-positive patients were older, frequently presented with encephalopathy, had lower rates of CSF pleocytosis and other neurological autoantibodies, and were less likely to receive immunotherapy. When SARS-CoV-2 seropositive versus seronegative cases with demyelinating disorders were compared no differences were seen. Whereas seropositive encephalitis patients less commonly showed increased CSF cells and protein, our data suggest that an antecedent symptomatic or asymptomatic SARS-CoV-2 infection can be detected in patients with autoimmune neurological conditions. These cases are rare, usually do not have specific neuroglial antibodies.

Central nervous system complications in SARS-CoV-2-infected patients

OBJECTIVE

To investigate the clinical manifestations, treatment and prognosis of COVID-19-associated central nervous system (CNS) complications.

METHODS

In this single-centre observation study, we recruited patients with COVID-19-associated CNS complications at the neurology inpatient department of the Eighth Affiliated Hospital, Sun Yat-Sen University (Futian, Shenzhen) from Dec 2022 to Feb 2023. Patients were analysed for demographics, clinical manifestations, cerebrospinal fluid properties, electroencephalographic features, neuroimaging characteristics, and treatment outcome. All patients were followed-up at 1 and 2 months after discharge until Apr 2023.

RESULTS

Of the 12 patients with COVID-19-associated CNS complications, the CNS symptoms occur between 0 days and 4 weeks after SARS-CoV-2 infection. The most common CNS symptoms were memory deficits (4/12, 33%), Unresponsiveness (4/12, 33%), mental and behavioural disorders (4/12, 33%). Seven of 12 cases can be categorized as probable SARS-CoV-2 encephalitis, and 5 cases can be described as brainstem encephalitis, acute disseminated encephalomyelitis, optic neuritis, multiple sclerosis or tremor probably associated with SARS-CoV-2 infection. Six patients received antiviral therapy, and 11 patients received glucocorticoid therapy, of which 3 patients received human immunoglobulin synchronously. Nine patients recovered well, two patients had residual neurological dysfunction, and one patient passed away from complications associated with tumor.

CONCLUSION

In this observational study, we found that the inflammatory or immune-related complications were relatively common manifestations of COVID-19-associated CNS complications, including different phenotypes of encephalitis and CNS inflammatory demyelinating diseases. Most patients recovered well, but a few patients had significant neurological dysfunctions remaining.

COVID-19 hospitalization increases the risk of developing glioblastoma: a bidirectional Mendelian-randomization study

BACKGROUND

As a result of the COVID-19 pandemic, patients with glioblastoma (GBM) are considered a highly vulnerable population. Despite this, the extent of the causative relationship between GBM and COVID-19 infection is uncertain.

METHODS

Genetic instruments for SARS-CoV-2 infection (38,984 cases and 1,644,784 control individuals), COVID-19 hospitalization (8,316 cases and 1,549,095 control individuals), and COVID-19 severity (4,792 cases and 1,054,664 control individuals) were obtained from a genome-wide association study (GWAS) from European populations. A total of 6,183 GBM cases and 18,169 controls from GWAS were enrolled in our study. Their associations were evaluated by applying Mendelian randomization (MR) including IVW meta-analysis, MR-Egger regression, and weighted-median analysis. To make the conclusions more robust and reliable, sensitivity analyses were performed.

RESULTS

Our results showed that genetically predicted COVID-19 hospitalization increases the risk of GBM (OR = 1.202, 95% CI = 1.035-1.395, p = 0.016). In addition, no increased risk of SARS-CoV-2 infection, COVID-19 hospitalization and severity were observed in patients with any type of genetically predicted GBM.

CONCLUSION

Our MR study indicated for the first time that genetically predicted COVID-19 hospitalization was demonstrated as a risk factor for the development of GBM.

COVID-19 and the risk of neuromyelitis optica spectrum disorder: a Mendelian randomization study

Background

An increasing number of studies have elucidated a close nexus between COVID-19 phenotypes and neuromyelitis optica spectrum disorder (NMOSD), yet the causality between them remains enigmatic.

Methods

In this study, we conducted a Mendelian randomization (MR) analysis employing summary data sourced from genome-wide association studies (GWAS) pertaining to COVID-19 susceptibility, hospitalization, severity, and NMOSD. The primary MR analysis employed the Inverse variance weighted (IVW) approach, which was supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. We implemented various sensitivity analyses including Cochran's Q test, MR-PRESSO method, MR-Egger intercept, leave-one-out analysis, and funnel plot.

Results

The MR results demonstrated a nominal association between COVID-19 susceptibility and the risk of AQP4+ NMOSD, as evidenced by the IVW method (OR = 4.958; 95% CI: 1.322-18.585; P = 0.018). Conversely, no causal association was observed between COVID-19 susceptibility, hospitalization, or severity and the increased risk of NMOSD, AQP4-NMOSD, or AQP4+ NMOSD. The comprehensive sensitivity analyses further bolstered the robustness and consistency of the MR estimates.

Conclusion

Our findings provide compelling evidence for a causal effect of COVID-19 phenotype on AQP4+ NMOSD, shedding new light on the understanding of the comorbidity between COVID-19 and NMOSD.

Secondary Central Nervous System Demyelinating Disorders in the Elderly: A Narrative Review

Secondary demyelinating diseases comprise a wide spectrum group of pathological conditions and may either be attributed to a disorder primarily affecting the neurons or axons, followed by demyelination, or to an underlying condition leading to secondary damage of the myelin sheath. In the elderly, primary demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis, are relatively uncommon. However, secondary causes of CNS demyelination may often occur and in this case, extensive diagnostic workup is usually needed. Infectious, postinfectious, or postvaccinal demyelination may be observed, attributed to age-related alterations of the immune system in this population. Osmotic disturbances and nutritional deficiencies, more commonly observed in the elderly, may lead to conditions such as pontine/extrapontine myelinolysis, Wernicke encephalopathy, and demyelination of the posterior columns of the spinal cord. The prevalence of malignancies is higher in the elderly, sometimes leading to radiation-induced, immunotherapy-related, or paraneoplastic CNS demyelination. This review intends to aid clinical neurologists in broadening their diagnostic approach to secondary CNS demyelinating diseases in the elderly. Common clinical conditions leading to secondary demyelination and their clinical manifestations are summarized here, while the current knowledge of the underlying pathophysiological mechanisms is additionally presented.

The Potential Role of SARS-CoV-2 Infection and Vaccines in Multiple Sclerosis Onset and Reactivation: A Case Series and Literature Review

The recent SARS-CoV-2 pandemic and related vaccines have raised several issues. Among them, the potential role of the viral infection (COVID-19) or anti-SARS-CoV-2 vaccines as causal factors of dysimmune CNS disorders, as well as the safety and efficacy of vaccines in patients affected by such diseases and on immune-active treatments have been analyzed. The aim is to better understand the relationship between SARS-CoV-2 infection/vaccines with dysimmune CNS diseases by describing 12 cases of multiple sclerosis/myelitis onset or reactivation after exposure to SARS-CoV-2 infection/vaccines and reviewing all published case reports or case series in which MS onset or reactivation was temporally associated with either COVID-19 (8 case reports, 3 case series) or anti-SARS-CoV-2 vaccines (13 case reports, 6 case series). All the cases share a temporal association between viral/vaccine exposure and symptoms onset. This finding, together with direct or immune-based mechanisms described both during COVID-19 and MS, claims in favor of a role for SARS-CoV-2 infection/vaccines in unmasking dysimmune CNS disorders. The most common clinical presentations involve the optic nerve, brainstem and spinal cord. The preferential tropism of the virus together with the presence of some host-related genetic/immune factors might predispose to the involvement of specific CNS districts.

Natural History of Untreated Optic Neuritis Associated With Mild COVID-19 Infection

This article describes a case of untreated optic neuritis occurring in the setting of coronavirus disease 2019 (COVID-19) infection and provides new insights into the natural history of this condition. A 29-year-old male patient with no known ocular or systemic disease presented with pain on extraocular movements and sudden loss of vision in the inferior visual field affecting the right eye. He had tested positive for COVID-19 six days prior after experiencing mild upper respiratory symptoms. On examination, visual acuity was 20/20, and color vision was normal. A relative afferent pupillary defect was observed in the right eye. Fundoscopy revealed mild optic disc edema in the same eye. Optical coherence tomography showed increased retinal nerve fiber layer thickness of the right optic nerve head and visual field testing revealed an inferonasal defect. Extensive laboratory and imaging investigations failed to reveal an underlying etiology, supporting a diagnosis of COVID-19-associated optic neuritis. The patient improved spontaneously without treatment. At the five-month follow-up, minor optic atrophy and a small residual visual field defect remained.

New onset or relapsing neuromyelitis optica temporally associated with SARS-CoV-2 infection and COVID-19 vaccination: a systematic review

Background

Neuromyelitis optica spectrum disorder (NMOSD) is a rare chronic neuroinflammatory autoimmune condition. Since the onset of the COVID-19 pandemic, there have been reports of NMOSD clinical manifestations following both SARS-CoV-2 infections and COVID-19 vaccinations.

Objective

This study aims to systematically review the published literature of NMOSD clinical manifestations associated with SARS-CoV-2 infections and COVID-19 vaccinations.

Methods

A Boolean search of the medical literature was conducted between December 1, 2019 to September 1, 2022, utilizing Medline, Cochrane Library, Embase, Trip Database, Clinicaltrials.gov, Scopus, and Web of Science databases. Articles were collated and managed on Covidence^® software. The authors independently appraised the articles for meeting study criteria and followed PRISMA guidelines. The literature search included all case reports and case series that met study criteria and involved NMOSD following either the SARS-CoV-2 infection or the COVID-19 vaccination.

Results

A total of 702 articles were imported for screening. After removing 352 duplicates and 313 articles based on exclusion criteria, 34 articles were analyzed. A total of 41 cases were selected, including 15 patients that developed new onset NMOSD following a SARS-CoV-2 infection, 21 patients that developed de novo NMOSD following COVID-19 vaccination, 3 patients with known NMOSD that experienced a relapse following vaccination, and 2 patients with presumed Multiple Sclerosis (MS) that was unmasked as NMOSD post-vaccination. There was a female preponderance of 76% among all NMOSD cases. The median time interval between the initial SARS-CoV-2 infection symptoms and NMOSD symptom onset was 14  days (range 3-120  days) and the median interval between COVID-19 vaccination and onset of NMO symptoms was 10  days (range 1 to 97  days). Transverse myelitis was the most common neurological manifestation in all patient groups (27/41). Management encompassed acute treatments such as high dose intravenous methylprednisolone, plasmapheresis, and intravenous immunoglobulin (IVIG) and maintenance immunotherapies. The majority of patients experienced a favorable outcome with complete or partial recovery, but 3 patients died.

Conclusion

This systematic review suggests that there is an association between NMOSD and SARS-CoV-2 infections and COVID-19 vaccinations. This association requires further study using quantitative epidemiological assessments in a large population to better quantify the risk.

Brain imaging and neuropsychological assessment of individuals recovered from a mild to moderate SARS-CoV-2 infection

As severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infections have been shown to affect the central nervous system, the investigation of associated alterations of brain structure and neuropsychological sequelae is crucial to help address future health care needs. Therefore, we performed a comprehensive neuroimaging and neuropsychological assessment of 223 nonvaccinated individuals recovered from a mild to moderate SARS-CoV-2 infection (100 female/123 male, age [years], mean ± SD, 55.54 ± 7.07; median 9.7 mo after infection) in comparison with 223 matched controls (93 female/130 male, 55.74 ± 6.60) within the framework of the Hamburg City Health Study. Primary study outcomes were advanced diffusion MRI measures of white matter microstructure, cortical thickness, white matter hyperintensity load, and neuropsychological test scores. Among all 11 MRI markers tested, significant differences were found in global measures of mean diffusivity (MD) and extracellular free water which were elevated in the white matter of post-SARS-CoV-2 individuals compared to matched controls (free water: 0.148 ± 0.018 vs. 0.142 ± 0.017, P < 0.001; MD [10-3 mm2/s]: 0.747 ± 0.021 vs. 0.740 ± 0.020, P < 0.001). Group classification accuracy based on diffusion imaging markers was up to 80%. Neuropsychological test scores did not significantly differ between groups. Collectively, our findings suggest that subtle changes in white matter extracellular water content last beyond the acute infection with SARS-CoV-2. However, in our sample, a mild to moderate SARS-CoV-2 infection was not associated with neuropsychological deficits, significant changes in cortical structure, or vascular lesions several months after recovery. External validation of our findings and longitudinal follow-up investigations are needed.

Central nervous system demyelinating diseases: glial cells at the hub of pathology

Inflammatory demyelinating diseases (IDDs) are among the main causes of inflammatory and neurodegenerative injury of the central nervous system (CNS) in young adult patients. Of these, multiple sclerosis (MS) is the most frequent and studied, as it affects about a million people in the USA alone. The understanding of the mechanisms underlying their pathology has been advancing, although there are still no highly effective disease-modifying treatments for the progressive symptoms and disability in the late stages of disease. Among these mechanisms, the action of glial cells upon lesion and regeneration has become a prominent research topic, helped not only by the discovery of glia as targets of autoantibodies, but also by their role on CNS homeostasis and neuroinflammation. In the present article, we discuss the participation of glial cells in IDDs, as well as their association with demyelination and synaptic dysfunction throughout the course of the disease and in experimental models, with a focus on MS phenotypes. Further, we discuss the involvement of microglia and astrocytes in lesion formation and organization, remyelination, synaptic induction and pruning through different signaling pathways. We argue that evidence of the several glia-mediated mechanisms in the course of CNS demyelinating diseases supports glial cells as viable targets for therapy development.

SARS-Cov-2 infection and neuropathological findings: a report of 18 cases and review of the literature

INTRODUCTION

COVID-19-infected patients harbour neurological symptoms such as stroke and anosmia, leading to the hypothesis that there is direct invasion of the central nervous system (CNS) by SARS-CoV-2. Several studies have reported the neuropathological examination of brain samples from patients who died from COVID-19. However, there is still sparse evidence of virus replication in the human brain, suggesting that neurologic symptoms could be related to mechanisms other than CNS infection by the virus. Our objective was to provide an extensive review of the literature on the neuropathological findings of postmortem brain samples from patients who died from COVID-19 and to report our own experience with 18 postmortem brain samples.

MATERIAL AND METHODS

We used microscopic examination, immunohistochemistry (using two different antibodies) and PCR-based techniques to describe the neuropathological findings and the presence of SARS-CoV-2 virus in postmortem brain samples. For comparison, similar techniques (IHC and PCR) were applied to the lung tissue samples for each patient from our cohort. The systematic literature review was conducted from the beginning of the pandemic in 2019 until June 1st, 2022.

RESULTS

In our cohort, the most common neuropathological findings were perivascular haemosiderin-laden macrophages and hypoxic-ischaemic changes in neurons, which were found in all cases (n = 18). Only one brain tissue sample harboured SARS-CoV-2 viral spike and nucleocapsid protein expression, while all brain cases harboured SARS-CoV-2 RNA positivity by PCR. A colocalization immunohistochemistry study revealed that SARS-CoV-2 antigens could be located in brain perivascular macrophages. The literature review highlighted that the most frequent neuropathological findings were ischaemic and haemorrhagic lesions, including hypoxic/ischaemic alterations. However, few studies have confirmed the presence of SARS-CoV-2 antigens in brain tissue samples.

CONCLUSION

This study highlighted the lack of specific neuropathological alterations in COVID-19-infected patients. There is still no evidence of neurotropism for SARS-CoV-2 in our cohort or in the literature.

COVID-19, post-acute COVID-19 syndrome (PACS, "long COVID") and post-COVID-19 vaccination syndrome (PCVS, "post-COVIDvac-syndrome"): Similarities and differences

Worldwide there have been over 760 million confirmed coronavirus disease 2019 (COVID-19) cases, and over 13 billion COVID-19 vaccine doses have been administered as of April 2023, according to the World Health Organization. An infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to an acute disease, i.e. COVID-19, but also to a post-acute COVID-19 syndrome (PACS, "long COVID"). Currently, the side effects of COVID-19 vaccines are increasingly being noted and studied. Here, we summarise the currently available indications and discuss our conclusions that (i) these side effects have specific similarities and differences to acute COVID-19 and PACS, that (ii) a new term should be used to refer to these side effects (post-COVID-19 vaccination syndrome, PCVS, colloquially "post-COVIDvac-syndrome"), and that (iii) there is a need to distinguish between acute COVID-19 vaccination syndrome (ACVS) and post-acute COVID-19 vaccination syndrome (PACVS) - in analogy to acute COVID-19 and PACS ("long COVID"). Moreover, we address mixed forms of disease caused by natural SARS-CoV-2 infection and COVID-19 vaccination. We explain why it is important for medical diagnosis, care and research to use the new terms (PCVS, ACVS and PACVS) in order to avoid confusion and misinterpretation of the underlying causes of disease and to enable optimal medical therapy. We do not recommend to use the term "Post-Vac-Syndrome" as it is imprecise. The article also serves to address the current problem of "medical gaslighting" in relation to PACS and PCVS by raising awareness among the medical professionals and supplying appropriate terminology for disease.

Relapsing Encephalomyelitis After COVID-19 Infection and Vaccination: From the National MS Society Case Conference Proceedings

Prior case studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its vaccines may unmask CNS neuroinflammatory conditions. We present a case of relapsing steroid-responsive encephalomyelitis after SARS-CoV-2 infection and subsequent COVID-19 vaccination. We also characterize the frequency of CNS neuroinflammatory events reported in the literature after both SARS-CoV-2 infection and COVID-19 vaccination.

Central Nervous System Neuroimmunologic Complications of COVID-19

Autoimmune disorders of the central nervous system following COVID-19 infection include multiple sclerosis (MS), neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody-associated disease, autoimmune encephalitis, acute disseminated encephalomyelitis, and other less common neuroimmunologic disorders. In general, these disorders are rare and likely represent postinfectious phenomena rather than direct consequences of the SARS-CoV-2 virus itself. The impact of COVID-19 infection on patients with preexisting neuroinflammatory disorders depends on both the disorder and disease-modifying therapy use. Patients with MS do not have an increased risk for severe COVID-19, though patients on anti-CD20 therapies may have worse clinical outcomes and attenuated humoral response to vaccination. Data are limited for other neuroinflammatory disorders, but known risk factors such as older age and medical comorbidities likely play a role. Prophylaxis and treatment for COVID-19 should be considered in patients with preexisting neuroinflammatory disorders at high risk for developing severe COVID-19.

SARS-CoV-2 pandemic as a model to assess the relationship between intercurrent viral infections and disease activity in Multiple Sclerosis: A propensity score matched case-control study

INTRODUCTION

An association between intercurrent viral respiratory infections and exacerbations of Multiple Sclerosis (MS) disease activity has been proposed by several studies. Considering the rapid spread of SARS-CoV2 worldwide and the systematic effort to immediately detect all incident cases with specific diagnostic tests, the pandemic can represent an interesting experimental model to assess the relationship between viral respiratory infections and MS disease activity.

AIMS AND METHODS

In this study, we have performed a propensity score matched case-control study with a prospective clinical/MRI follow-up, on a cohort of relapsing-remitting MS (RRMS) patients who tested positive for SARS-CoV2 in the period 2020-2022, with the aim to evaluate if the SARS-CoV2 infection influences the short-term risk of disease activity. Controls (RRMS patients not exposed to SARS-CoV-2, using 2019 as the reference period) were matched 1:1 with cases for age, EDSS, sex and disease-modifying treatment (DMT) (moderate efficacy vs high efficacy). Differences in relapses, MRI disease activity and confirmed disabilty worsening (CDW) between cases in the 6 months following the SARS-CoV-2 infection, and controls in a similar 6 months reference period in 2019 were compared.

RESULTS

We identified 150 cases of SARS-CoV2 infection in the period March 2020 - March 2022, out of a total population of approximately 1500 MS patients, matched with 150 MS patients not exposed to SARS-CoV2 (controls). Mean age was 40.9 ± 12.0 years in cases and 42.0 ± 10.9 years in controls, mean EDSS was 2.54±1.36 in cases and 2.60±1.32 in controls. All patients were treated with a DMT, and a considerable proportion with a high efficacy DMT (65.3% in cases and 66% in controls), reflecting a typical real world RRMS population. 52.8% of patients in this cohort had been vaccinated with a mRNA Covid-19 vaccine. We did not observe a significant difference in relapses (4.0% cases, 5.3% controls; p = 0.774), MRI disease activity (9.3% cases, 8.0% controls; p = 0.838), CDW (5.3% cases, 6.7% controls; p = 0.782) in the 6 months after SARS-CoV-2 infection between cases and controls.

CONCLUSION

Using a propensity score matching design and including both clinical and MRI data, this study does not suggest an increased risk of MS disease activity following SARS-CoV-2 infection. All MS patients in this cohort were treated with a DMT, and a considerable number with a high efficacy DMT. These results therefore may not be applicable to untreated patients, for which the risk of increased MS disease activity after SARS-CoV-2 infection may not be excluded. A possible hypothesis explaining these results could be that SARS-CoV2 is less prone, compared to other viruses, to induce exacerbations of MS disease activity; another possible interpretation of these data might be that DMT is able to effectively suppress the increase of disease activity triggered by SARS-CoV2 infection.

Neuroimaging of COVID-19

We review the wide variety of common neuroimaging manifestations related to coronavirus disease 2019 (COVID-19) and COVID therapies, grouping the entities by likely pathophysiology, recognizing that the etiology of many entities remains uncertain. Direct viral invasion likely contributes to olfactory bulb abnormalities. COVID meningoencephalitis may represent direct viral infection and/or autoimmune inflammation. Para-infectious inflammation and inflammatory demyelination at the time of infection are likely primary contributors to acute necrotizing encephalopathy, cytotoxic lesion of the corpus callosum, and diffuse white matter abnormality. Later postinfectious inflammation and demyelination may manifest as acute demyelinating encephalomyelitis, Guillain-Barré syndrome, or transverse myelitis. The hallmark vascular inflammation and coagulopathy of COVID-19 may produce acute ischemic infarction, microinfarction contributing to white matter abnormality, space-occupying hemorrhage or microhemorrhage, venous thrombosis, and posterior reversible encephalopathy syndrome. Adverse effects of therapies including zinc, chloroquine/hydroxychloroquine, antivirals, and vaccines, and current evidence regarding "long COVID" is briefly reviewed. Finally, we present a case of bacterial and fungal superinfection related to immune dysregulation from COVID.

Longitudinal extensive transverse myelitis due to tuberculosis: A case report

Neurotuberculosis is a potentially fatal disease that can present with upper or lower motor neuron symptoms. Longitudinally extensive transverse myelitis (LETM) is characterized by contiguous inflammatory lesions of the spinal cord extending to three or more vertebral segments. The causes of LETM include infections, neoplasm, and autoimmune diseases. Mycobacterium tuberculosis is a rare cause of transverse myelitis. Here, we report a 21-year-old Afghan female who was referred with chronic progressive quadriparesis and showed LETM on cervical MRI. This report indicates that tuberculosis should be considered as a differential diagnosis of LETM, especially in endemic areas.

Shared miRNA landscapes of COVID-19 and neurodegeneration confirm neuroinflammation as an important overlapping feature

Introduction

Development and worsening of most common neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis, have been associated with COVID-19 However, the mechanisms associated with neurological symptoms in COVID-19 patients and neurodegenerative sequelae are not clear. The interplay between gene expression and metabolite production in CNS is driven by miRNAs. These small non-coding molecules are dysregulated in most common neurodegenerative diseases and COVID-19.

Methods

We have performed a thorough literature screening and database mining to search for shared miRNA landscapes of SARS-CoV-2 infection and neurodegeneration. Differentially expressed miRNAs in COVID-19 patients were searched using PubMed, while differentially expressed miRNAs in patients with five most common neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis) were searched using the Human microRNA Disease Database. Target genes of the overlapping miRNAs, identified with the miRTarBase, were used for the pathway enrichment analysis performed with Kyoto Encyclopedia of Genes and Genomes and Reactome.

Results

In total, 98 common miRNAs were found. Additionally, two of them (hsa-miR-34a and hsa-miR-132) were highlighted as promising biomarkers of neurodegeneration, as they are dysregulated in all five most common neurodegenerative diseases and COVID-19. Additionally, hsa-miR-155 was upregulated in four COVID-19 studies and found to be dysregulated in neurodegeneration processes as well. Screening for miRNA targets identified 746 unique genes with strong evidence for interaction. Target enrichment analysis highlighted most significant KEGG and Reactome pathways being involved in signaling, cancer, transcription and infection. However, the more specific identified pathways confirmed neuroinflammation as being the most important shared feature.

Discussion

Our pathway based approach has identified overlapping miRNAs in COVID-19 and neurodegenerative diseases that may have a valuable potential for neurodegeneration prediction in COVID-19 patients. Additionally, identified miRNAs can be further explored as potential drug targets or agents to modify signaling in shared pathways. Graphical AbstractShared miRNA molecules among the five investigated neurodegenerative diseases and COVID-19 were identified. The two overlapping miRNAs, hsa-miR-34a and has-miR-132, present potential biomarkers of neurodegenerative sequelae after COVID-19. Furthermore, 98 common miRNAs between all five neurodegenerative diseases together and COVID-19 were identified. A KEGG and Reactome pathway enrichment analyses was performed on the list of shared miRNA target genes and finally top 20 pathways were evaluated for their potential for identification of new drug targets. A common feature of identified overlapping miRNAs and pathways is neuroinflammation. AD, Alzheimer's disease; ALS, amyotrophic lateral sclerosis; COVID-19, coronavirus disease 2019; HD, Huntington's disease; KEGG, Kyoto Encyclopedia of Genes and Genomes; MS, multiple sclerosis; PD, Parkinson's disease.

Potential molecular mechanisms of chronic fatigue in long haul COVID and other viral diseases

Historically, COVID-19 emerges as one of the most devastating diseases of humankind, which creates an unmanageable health crisis worldwide. Until now, this disease costs millions of lives and continues to paralyze human civilization's economy and social growth, leaving an enduring damage that will take an exceptionally long time to repair. While a majority of infected patients survive after mild to moderate reactions after two to six weeks, a growing population of patients suffers for months with severe and prolonged symptoms of fatigue, depression, and anxiety. These patients are no less than 10% of total COVID-19 infected individuals with distinctive chronic clinical symptomatology, collectively termed post-acute sequelae of COVID-19 (PASC) or more commonly long-haul COVID. Interestingly, Long-haul COVID and many debilitating viral diseases display a similar range of clinical symptoms of muscle fatigue, dizziness, depression, and chronic inflammation. In our current hypothesis-driven review article, we attempt to discuss the molecular mechanism of muscle fatigue in long-haul COVID, and other viral diseases as caused by HHV6, Powassan, Epstein-Barr virus (EBV), and HIV. We also discuss the pathological resemblance of virus-triggered muscle fatigue with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

SARS-CoV-2 infection and multi-organ system damage: A review

The SARS-CoV-2 infection causes COVID-19, which has affected approximately six hundred million people globally as of August 2022. Organs and cells harboring angiotensin-converting enzyme 2 (ACE2) surface receptors are the primary targets of the virus. However, once it enters the body through the respiratory system, the virus can spread hematogenously to infect other body organs. Therefore, COVID-19 affects many organs, causing severe and long-term complications, even after the disease has ended, thus worsening the quality of life. Although it is known that the respiratory system is most affected by the SARS-CoV-2 infection, many organs/systems are affected in the short and long term. Since the COVID-19 disease simultaneously affects many organs, redesigning diagnostic and therapy policies to fit the damaged organs is strongly recommended. Even though the pathophysiology of many problems the infection causes is unknown, the frequency of COVID-19 cases rises with age and the existence of preexisting symptoms. This study aims to update our knowledge of SARS-CoV-2 infection and multi-organ dysfunction interaction based on clinical and theoretical evidence. For this purpose, the study comprehensively elucidates the most recent studies on the effects of SARS-CoV-2 infection on multiple organs and systems, including respiratory, cardiovascular, gastrointestinal, renal, nervous, endocrine, reproductive, immune, and parts of the integumentary system. Understanding the range of atypical COVID-19 symptoms could improve disease surveillance, limit transmission, and avoid additional multi-organ-system problems.