Neuroimaging Patterns in Patients with COVID-19-Associated Neurological Complications: A Review

Could the Cerebral Involvement of COVID-19 Disease be Related to Microstructural Changes that are not Reflected in Conventional MRI Images?

In patients with COVID-19, neurodegeneration may develop before clinical symptoms appear. Diffusion-weighted (DW) MRI is an important technique for analyzing microstructural changes such as gliosis. In this study, a quantitative evaluation of microstructural changes in the brain with apparent diffusion coefficient (ADC) values in patients presenting with a headache after the COVID-19 disease was analyzed and compared. DW MR images of patients of 20 COVID-19 patients (13 females, 7 males) who required imaging due to headache; 20 controls (16 females, 4 males) were retrospectively reevaluated. ADC measurements were taken from 16 regions of the brain, including right and left symmetrical in patients with COVID-19 infections and control groups. All regions of interest (ROIs) were taken from the hypothalamus, parahippocampus, thalamus, corpus striatum, cingulate gyrus, occipital gyrus, dentate nucleus, and medulla oblongata posterior. ADC values in the dentate nucleus right (784.6 ± 75.7 vs. 717.25 ± 50.75), dentate nucleus left (768.05 ± 69.76 vs. 711.40 ± 52.99), right thalamus (731.15 ± 38.14 vs. 701.60 ± 43.65), left thalamus (744.05 ± 39.00 vs. 702.85 ± 28.88), right parahippocampus (789.10 ± 56.35 vs. 754.75 ± 33.78), right corpus striatum (710.00 ± 39.81 vs. 681.55 ± 39.84) were significantly higher than those in the control group. No significant changes were observed in other areas. A significant increase in ADC values at many levels in the brain in patients with COVID-19 disease and headache was observed. Thus, this study indicates that cerebral involvement in COVID-19 disease may be related to microstructural changes that are not reflected in conventional MRI images.

COVID-19 related acute necrotizing encephalopathy presenting in the early postoperative period

Besides respiratory and gastrointestinal symptoms, SARS-CoV-2 also has potential neurotropic effects. Acute hemorrhagic necrotizing encephalopathy is a rare complication of Covid-19. This article presents a case of an 81-year-old female, fully vaccinated, who underwent laparoscopic transhiatal esophagectomy due to gastroesophageal junction cancer. In the early postoperative period, the patient developed persistent fever accompanied by acute quadriplegia, impaired consciousness, and no signs of respiratory distress. Imaging with Computed Tomography and Magnetic Resonance revealed multiple bilateral lesions both in gray and white matter, as well as pulmonary embolism. Covid-19 infection was added to the differential diagnosis three weeks later, after other possible causes were excluded. The molecular test obtained at that time for coronavirus was negative. However, the high clinical suspicion index led to Covid-19 antibody testing (IgG and IgA), which confirmed the diagnosis. The patient was treated with corticosteroids with noticeable clinical improvement. She was discharged to a rehabilitation center. Six months later, the patient was in good general condition, although a neurological deficit was still present. This case indicates the significance of a high clinical suspicion index, based on a combination of clinical manifestations and neuroimaging, and the confirmation of the diagnosis with molecular and antibody testing. Constant awareness of a possible Covid-19 infection among hospitalized patients is mandatory.

Ischemic and Hemorrhagic Cerebrovascular Events Related to COVID-19 Coagulopathy and Hypoxemia

Since the very beginning of the COVID-19 pandemic, numerous researchers have made an effort to determine the molecular composition of the SARS-CoV-2 virus, and the exact pathomechanism through which the virus exerts such a devastating effect on the host/infected organism. Recent scientific evidence highlights the affinity of the virus towards ACE2 receptors, which are widespread in multiple human systems, including the central nervous system (CNS) and cerebral vessels. Such an affinity may explain endothelial dysfunction and damage that is observed in COVID-positive patients in histopathological studies, with subsequent dysregulation of the cerebral circulation leading to transient or acute cerebrovascular accidents. In this paper, we aimed to evaluate the effects of COVID-related hypoxemia and direct viral invasion on the cerebral circulation, with special respect to the postulated pathomechanism, vulnerable groups of patients, clinical course and outcomes, as well as diagnostic imaging findings.

COVID-19 and Stroke Trends in A Tertiary Care Center from South India -Our Monsoon Experience

INTRODUCTION

The unprecedented challenges during the COVID pandemic and the subsequent lockdown had resulted in a delay in treatment metrics for acute stroke. There is a rising concern that COVID-19 co-infection can adversely affect stroke outcome. We aim to investigate the impact of COVID-19 in the management of stroke patients. We also compared the differences in stroke manifestations, etiological pattern, treatment course, and outcome of acute stroke patients in COVID-19 confirmed cases.

METHODOLOGY

A single-center retrospective study was done at the Stroke Unit, Government Medical College, Thiruvananthapuram. Consecutive patients of acute stroke confirmed by imaging, presenting within 24 hours of the onset of symptoms in May to July 2020 and May to July 2019, were included. The primary data variables included baseline demographics, risk factors, admission NIHSS, stroke timings, thrombolysis rate, TOAST etiology, mRS at discharge, and in-hospital mortality.

RESULTS

Strokes with higher NIHSS, arrival blood sugar and blood pressure, and delays in door-to-CT and door-to-needle time were more during the pandemic. Intravenous thrombolysis was less and mortality was higher in COVID-19 strokes during the pandemic. COVID-19-positive stroke patients had more hemorrhagic strokes, more severe strokes with low CT ASPECTS, more hemorrhagic transformation, high in-hospital mortality, and poor functional outcome at discharge and 3 months.

CONCLUSION

Our study was a hypothesis-generating study with a limited number of patients. This study has reconfirmed the higher severity of the stroke, with a higher mRS score and mortality during the pandemic, especially among COVID-19-positive stroke patients.

Basal Ganglia Autoimmune Encephalitis Following Leptospirosis

Basal ganglia encephalitis is a part of the spectrum of autoimmune basal ganglia disorders. We are reporting a child who had a fever with focal seizures followed by behavioral problems, rigidity, bradykinesia, and dystonia. His parkinsonism-like features were increasing day by day up to the level that the child was non-ambulatory. His initial Magnetic Resonance Imaging (MRI) of the brain showed asymmetrical T2 hyperintensities involving both the caudate nuclei and putamina. Later, with progressive symptoms, repeat MRI revealed a swelling and symmetrical signal change in both the caudate nuclei and putamina in the form of T2 and Fluid-attenuated inversion recovery (FLAIR) hyperintensities. In addition, there was T2 hyperintensity involving bilateral substantia nigra. Serum basal ganglia antibody, Leptospira Immunoglobulin M (IgM) antibody was positive, and Cerebrospinal Fluid (CSF) oligoclonal band was positive. So, the child was diagnosed with post-leptospirosis autoimmune basal ganglia encephalitis. He was managed with immunomodulatory agents and significant improvement in the symptoms with mild residual extrapyramidal symptoms were noted.

Antineutrophil Cytoplasmic Autoantibodies-Associated Vasculitides and Risk of Stroke: A Systematic Review and Meta-analysis

BACKGROUND

Increased incidence of cardiovascular disease, including stroke, has been consistently observed in patients with chronic inflammatory diseases, although data on antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides (AAV) are still limited due to the relative rarity of the disease.

METHODS

Two investigators independently searched published studies indexed in MEDLINE and EMBASE database from inception to June 2019 using the search terms related to AAV and stroke. The eligible study must be cohort study that consisted of cohort of patients with AAV and cohort of patients without AAV. The study must follow the participants for incident stroke. The magnitude of difference in the incidence of stoke between the cohorts must be reported. Pooled effect estimates were calculated by combining the effect estimate of each eligible study using generic inverse variance method. Statistical heterogeneity was assessed using the Cochran's Q test and I² statistics. All analyses were conducted using RevMan 5.3 software from the Cochrane Collaboration.

RESULTS

A total of six cohort studies fulfilled the eligibility criteria and were included into the meta-analysis. Patients with AAV had a higher risk of developing incident stroke than individuals without AAV with the a pooled risk ratio of 2.02 (95% CI, 1.02-4.00; I² of 89%). Funnel revealed no suggestive evidence of publication bias.

CONCLUSION

A significantly higher risk of incident stroke among patients with AAV than individuals without AAV was demonstrated by this meta-analysis.

Incidence of white matter lesions in hospitalized COVID-19 patients: A meta-analysis

OBJECTIVE

Novel coronavirus disease 2019 (COVID-19) has been found to be associated with encephalopathy and brain imaging abnormalities. The identification of incident white matter lesions, known to be associated with cerebral microcirculatory failure and cerebrovascular disease, in COVID-19 patients is of clinical and scientific interest. We performed a meta-analysis to investigate the incidence of white matter lesions (WMLs) in hospitalized COVID-19 patients.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched for studies on brain imaging abnormalities in hospitalized COVID-19 patients. The terms used included "white matter lesions," "white matter hyperintensity," "COVID-19," "coronavirus," and "SARS-CoV-2." A random-effects meta-analysis was conducted to obtain a pooled estimate of WML prevalence in hospitalized COVID-19 patients.

RESULTS

A total of 4 eligible studies involving 362 patients (144 with WMLs and 218 without) were included in the meta-analysis. We found the pooled estimate of WML prevalence to be 20% (ES 0.20; 95% CI 0.00-0.54; p = .03).

CONCLUSIONS

The estimated pooled prevalence rate of WMLs was approximately 20% in hospitalized COVID-19 patients, albeit lower than the crude prevalence rate (39.8%).

An Imaging Overview of COVID-19 ARDS in ICU Patients and Its Complications: A Pictorial Review

A significant proportion of patients with COVID-19 pneumonia could develop acute respiratory distress syndrome (ARDS), thus requiring mechanical ventilation, and resulting in a high rate of intensive care unit (ICU) admission. Several complications can arise during an ICU stay, from both COVID-19 infection and the respiratory supporting system, including barotraumas (pneumothorax and pneumomediastinum), superimposed pneumonia, coagulation disorders (pulmonary embolism, venous thromboembolism, hemorrhages and acute ischemic stroke), abdominal involvement (acute mesenteric ischemia, pancreatitis and acute kidney injury) and sarcopenia. Imaging plays a pivotal role in the detection and monitoring of ICU complications and is expanding even to prognosis prediction. The present pictorial review describes the clinicopathological and radiological findings of COVID-19 ARDS in ICU patients and discusses the imaging features of complications related to invasive ventilation support, as well as those of COVID-19 itself in this particularly fragile population. Radiologists need to be familiar with COVID-19's possible extra-pulmonary complications and, through reliable and constant monitoring, guide therapeutic decisions. Moreover, as more research is pursued and the pathophysiology of COVID-19 is increasingly understood, the role of imaging must evolve accordingly, expanding from the diagnosis and subsequent management of patients to prognosis prediction.

Neurological manifestations and pathogenic mechanisms of COVID-19

Coronavirus disease (COVID-19) arising from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection has caused a worldwide pandemic, mainly owing to its highly virulent nature stemming from a very strong and highly efficacious binding to the angiotensin converting enzyme-2 (ACE2) receptor. As the pandemic developed, increasing numbers of COVID-19 patients with neurological manifestations were reported, strongly suggesting a causal relationship. Indeed, direct invasion of SARS-CoV-2 viral particles into the brain can occur through the cribriform plate via olfactory nerves, passage through a damaged blood-brain-barrier, or via haematogenic infiltration of infected leukocytes. Neurological complications range from potentially fatal encephalopathy and stroke, to the onset of headaches and dizziness, which despite their apparent innocuous presentation may still imply a more sinister pathology. Here, we summarize the most recent knowledge on the neurological presentations typically being associated with COVID-19, whilst providing potential pathophysiological mechanisms. The latter are centered upon hypoxic brain injury, generation of a cytokine storm with attendant immune-mediated damage, and a prothrombotic state. A better understanding of both the neuroinvasive properties of SARS-CoV-2 and the neurological complications of COVID-19 will be important to improve patient outcomes.

[COVID-19: neurological manifestations-update : What we know so far]

Beyond pulmonary presentation, COVID-19 infection can manifest with a variety of both acute and chronic neurologic and neuropsychiatric (concomitant) symptoms and diseases. Nonspecific symptoms such as headache, fatigue, olfactory and gustatory disturbance have been reported more frequently, and severe disease such as encephalopathy, encephalitis, and cerebrovascular events have been reported relatively rarely. The heterogeneity of neurologic and neuropsychiatric presentations is large, as well as the range of recorded prevalences. Older patients, pre-existing neurologic and non neurologic comorbidities and severe COVID-19 disease were associated with increased risk of severe neurologic complications and higher in-hospital mortality. Probable neurotropic pathomechanisms of SARS-CoV‑2 have been discussed, but a multifactorial genesis of neurologic/neuropsychiatric symptoms and disease beyond these is likely.