Neurological Complications of COVID-19

The neurological complications of COVID-19 are an expansive and heterogeneous topic. This chapter discusses the neuropathophysiology of COVID-19 and the potential mechanisms through which the disease leads to neurological manifestations while also exploring historical viruses that have also led to neurological sequelae. These complications are then characterized and classified into several groups with support from contemporaneous evidence. In addition to this we examine common neurological imaging and their findings and finally discuss the greatest needs moving forward with regard to evidence and research through collaborative efforts. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Eye Disorders and Neuro-ophthalmic Manifestations of COVID-19

Growing data are confirming the association between the novel coronavirus disease (COVID-19) and eye disorders, including ocular alterations and neuro-ophthalmic manifestations. The main pathophysiological mechanisms considered included a direct infection through the ocular surface, a post-viremia secretion of the virus from the lacrimal glands, and a viral dissemination through the bloodstream. According to the different ways of contagion, different structures could be involved.The most common ocular symptoms reported in COVID-19 patients were dry eye, redness, tearing, itching and pain. Among symptomatic patients, most of them presented conjunctivitis. Considering the posterior chamber, retinal artery and vein occlusions were described in few clinical reports;moreover, some studies presented cases of paracentral acute middle maculopathy occurring in COVID-19 patients. The involvement of the choroid seems to be rare, and a single case of atypical choroiditis was currently described. Between neuro-ophthalmic manifestations, optic neuritis appear to be relatively frequent and generally not associated with magnetic resonance imaging abnormalities. Some reports showed the involvement of the ocular motor nerves, often presenting with palsy. Miller Fisher syndrome has been showed in rare cases;however, this association could be corroborated by the several reports describing Guillain-Barré syndrome occurrence in COVID-19 patients.In line with well-known previous viral infection, COVID-19 seems to be associated with eye involvement. Thus, ocular and neuro-ophthalmic symptoms and signs should be carefully assessed and monitored in these patients. To reach this purpose, it is critical to implement remote diagnostic techniques. Moreover, the comprehension of the pathogenetic mechanisms is still scarce and no standardized diagnostic protocol was established for these patients, making necessary further studies to improve current understandings. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Global uncertainty in the diagnosis of neurological complications of SARS-CoV-2 infection by both neurologists and non-neurologists: An international inter-observer variability study.

INTRODUCTION: Uniform case definitions are required to ensure harmonised reporting of neurological syndromes associated with SARS-CoV-2. Moreover, it is unclear how clinicians perceive the relative importance of SARS-CoV-2 in neurological syndromes, which risks under- or over-reporting. METHODS: We invited clinicians through global networks, including the World Federation of Neurology, to assess ten anonymised vignettes of SARS-CoV-2 neurological syndromes. Using standardised case definitions, clinicians assigned a diagnosis and ranked association with SARS-CoV-2. We compared diagnostic accuracy and assigned association ranks between different settings and specialties and calculated inter-rater agreement for case definitions as "poor" (κ ≤ 0.4), "moderate" or "good" (κ > 0.6). RESULTS: 1265 diagnoses were assigned by 146 participants from 45 countries on six continents. The highest correct proportion were cerebral venous sinus thrombosis (CVST, 95.8%), Guillain-Barré syndrome (GBS, 92.4%) and headache (91.6%) and the lowest encephalitis (72.8%), psychosis (53.8%) and encephalopathy (43.2%). Diagnostic accuracy was similar between neurologists and non-neurologists (median score 8 vs. 7/10, p = 0.1). Good inter-rater agreement was observed for five diagnoses: cranial neuropathy, headache, myelitis, CVST, and GBS and poor agreement for encephalopathy. In 13% of vignettes, clinicians incorrectly assigned lowest association ranks, regardless of setting and specialty. CONCLUSION: The case definitions can help with reporting of neurological complications of SARS-CoV-2, also in settings with few neurologists. However, encephalopathy, encephalitis, and psychosis were often misdiagnosed, and clinicians underestimated the association with SARS-CoV-2. Future work should refine the case definitions and provide training if global reporting of neurological syndromes associated with SARS-CoV-2 is to be robust.