Cerebellar infarction requiring surgical decompression in patient with COVID 19 pathological analysis and brief review

Mechanisms of COVID-19-induced cerebellitis

The COVID-19 pandemic caused by SARS-CoV2 has raised several important health concerns, not least increased mortality and morbidity. SARS-CoV2 can infect the central nervous system via hematogenous or transneuronal routes, acting through different receptors including ACE2, DPP4, and neuropilin 1 and cause several issues, including the focus here, cerebellitis. The cerebellum is an essential part of the CNS located adjacent to the brainstem with a complex micro and macroscopic structure. The cerebellum plays several physiological roles, such as coordination, cognition, and executive functioning. Damage to the cerebellum can lead to incoordination and ataxia. In our narrative review, we searched different databases from 2021 to 2022 with the keywords cerebellum and COVID-19; 247 studies were identified and reviewed, focusing on clinical studies and excluding non-clinical studies; 56 studies were finally included for analysis. SARS-CoV2 infection of the cerebellum can be seen to be assessed through many methods such as MRI, PET, CT, postmortem studies, and histological findings. These methodological studies have demonstrated that cerebellar infection with COVID-19 can bring about several sequelae: thrombosis, microbleed, hemorrhage, stroke, autoantibody production, ataxia, and widespread inflammation in the cerebellum. Such central effects are likely to exacerbate the known multiorgan effects of SARS-CoV2 and should also be considered as part of disease prognosis.

Ischemic stroke in 455 COVID-19 patients

There is increasing evidence that COVID-19 can be associated with ischemic stroke (COVID-stroke). The frequency and pathogenesis of COVID-stroke, however, remains largely unknown. This narrative review aimed at summarizing and discussing current knowledge about frequency and pathogenesis of COVID-stroke in 455 patients collected from the literature. COVID-stroke occurs in all age groups and predominantly in males. The anterior circulation is more frequently affected than the posterior circulation. COVID-stroke is most frequently embolic. The severity of COVID-stroke ranges from NIHSS 3 to 32. Cardiovascular risk factors are highly prevalent in patients with COVID-stroke. COVID-stroke occurs simultaneously with the onset of pulmonary manifestations or up to 40 days later. Clinical manifestations of COVID-19 are most frequently mild or even absent. The majority of patients with COVID-stroke achieve complete or partial recovery, but in one-quarter of patients, the outcome is fatal. In conclusion, the frequency of ischemic stroke has not increased since the outbreak of the SARS-CoV-2 pandemic. COVID-stroke predominantly affects males and the anterior circulation. COVID-stroke is multifactorial but predominantly embolic and more frequently attributable to cardiovascular risk factors than to coagulopathy.

A case-based systematic review on the SARS-COVID-2-associated cerebrovascular diseases and the possible virus routes of entry

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sparked a global pandemic that continues to affect various facets of human existence. Many sources reported virus-induced acute cerebrovascular disorders. Systematically, this paper reviews the case studies of COVID-19-related acute cerebrovascular diseases such as ischaemic stroke, intracerebral hemorrhage, and cerebral sinus thrombosis. We also spoke about how SARS-CoV-2 can infect the brain and trigger the aforementioned disorders. We stated that SARS-CoV-2 neuroinvasion and BBB dysfunction could cause the observed disorders; however, further research is required to specify the mechanisms and pathogenesis of the virus.

Neuropathologic findings of patients with COVID-19: a systematic review

BACKGROUND

Despite the expanding literature that discusses insights into the clinical picture and mechanisms by which the SARS-CoV-2 virus invades the nervous system, data on the neuropathologic findings of patients who died following SARS-CoV-2 infection is limited.

METHODS

A broad literature search was done for published articles that reported on histopathological findings of the brain in patients with COVID-19 in PubMed by MEDLINE, Embase, CENTRAL by the Cochrane Library, and SCOPUS from December 31, 2019 to October 31, 2020.

RESULTS

The systematic literature search strategy used resulted in a total of 1608 articles of which 14 were included in the analysis (PROSPERO registration number: CRD42020221022). There were ten case series, two case reports, one retrospective cohort, and one prospective cohort. The age of the patients ranged between 38 and 90 years old, most of them older than 65 years old (n=66, 45.2%) and males (n=79, 54.1%). Most tested negative in SARS-CoV-2 immunohistochemistry (n=70, 47.9%). The striking pathologic changes included diffuse edema (n=25, 17.1%), gliosis with diffuse activation of microglia and astrocytes (n=52, 35.6%), infarctions involving cortical and subcortical areas of the brain (n=4, 2.7%), intracranial bleed (subarachnoid hemorrhage and punctate hemorrhages) (n=18, 12.4%), arteriosclerosis (n=43, 29.5%), hypoxic-ischemic injury (n=41, 28.1%), and signs of inflammation (n=52, 35.6%). The cause of death was attributed to the cardiorespiratory system (n=66, 45.2%).

CONCLUSIONS

The neuropathologic changes observed likely represent direct cytopathic effects and indirect effects secondary to host-specific inflammatory response induced by the viral infection. Further studies however are required to better elucidate the pathologic mechanism.

COVID-19 and stroke: from the cases to the causes

During COVID-19 pandemic, a wide variety of stroke typologies have been described in patients affected by SARS-CoV-2. Investigating the case reports of acute stroke in COVID-19 patients, published since the beginning of the pandemic, we tried to trace the pathogenic mechanisms of stroke during SARS-CoV-2 infection. We conducted a systematic review analyzing demographic data, cerebrovascular risk factors, NIHSS score, vascular territory involvement and laboratory findings of 168 patients described in 89 studies, from a pool of 1243 records. Based on our results, we have identified different stroke profiles: (1) cerebral large vessel disease (CLVD) profile with a low disability, simultaneous onset of COVID-19 and stroke symptoms, good outcome and low serum levels of D-dimer and CRP; (2) intracranial bleeding (IB) profile with high disability, poor outcome and low levels of serum markers of inflammation and coagulopathy; (3) CLVD profile with a short time-lapse between COVID-19 symptoms and stroke onset, high neurological disability and very high systemic inflammatory markers; (4) multiple thrombo-embolic disease (MTED) profile with older patients, many comorbidities, disabling stroke, poor outcome, evident alteration of coagulation tests and high serum levels of both D-dimer and CRP. We therefore summarized these different profiles in a spectrum similar to that of visible light, where the violet-blue band included IB and CSVD with low inflammation and prothrombotic activity, the green-yellow band included CLVD with high inflammation and moderate prothrombotic activity and the orange-red band for MTED with moderate-high levels of inflammation and very high prothrombotic activity.