Autoimmune limbic encephalitis related to SARS-CoV-2 infection: Case-report and review of the literature

BACKGROUND: SARS-CoV-2 infection is associated with a wide spectrum of neurological complications, including encephalitis. Most cases showed features consistent with a central nervous system (CNS) cytokine-mediated damage. However, few cases arguing for an autoimmune mechanism have been described, mainly as single reports or sparse in large case series involving other CNS manifestations. In this paper, we described a case of definite autoimmune limbic encephalitis (LE) COVID-19 related and reviewed the existing literature on other reported cases. CASE REPORT: Two weeks after the onset of COVID-19 infection, a 74-year-old woman presented with subacute confusion and focal motor seizures with impaired awareness, starting from left temporal region. Cerebrospinal fluid analysis revealed hyperproteinorrachia. Brain MRI showed bilateral T2/FLAIR hyperintensities in both hippocampi and total body PET/TC scan revealed hypermetabolism in basal ganglia bilaterally. A diagnosis of autoimmune LE was made. Thus, high dose corticosteroids and antiseizure medications were started, with a marked improvement of neurological conditions. LITERATURE REVIEW: We systematically reviewed the literature to identify all well-documented cases of definite autoimmune LE (according to Graus criteria) in patients with COVID-19 infection, identifying other five cases exhibiting a good response to immunomodulating therapy. CONCLUSION: A very limited number of autoimmune LE have been described until now. It is important to monitor neurological symptoms in COVID-19 patients and to consider the possibility of an autoimmune LE, in particular when altered mental status and seizures appear late in the disease course. This allows to promptly start the appropriate treatments and avoid unnecessary delays.