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

Post-COVID-19 opsoclonus-myoclonus syndrome and encephalopathy associated with leucine-rich glioma-inactivated 1 (LGI-1) antibodies

“…These include anti-NMDA-R encephalitis [ 2 ], anti-CASPR-2 encephalitis [ 3 ], anti-myelin associated glycoprotein (MOG)-associated encephalitis [ 4 ] and Bickerstaff encephalitis [ 5 ]. Antibody-negative limbic encephalitis has also been described, as has Guillain-Barre syndrome and its variants [ 1 , 6 ]. The patient described in this case developed opsoclonus-myoclonus and encephalopathy associated with LGI-1 antibodies, with onset 6 days after the start of COVID-19 symptoms.…”

Limbic Encephalitis Associated with COVID-19

“…When all three criteria are met, a diagnosis of LE can be made. Therefore, analyzed studies [10,21,23,25,32] show that para-infectious LE, associated with SARS-CoV-2, can be considered as an independent disease, which should be studied more because the possible consequences for patients and society are unclear, while the frequency and prognosis of this disease still need to be clarified. Interestingly, it is possible for para-infectious LE, associated with SARS-CoV-2 to occur in patients with respiratory system involvement, as well as in patients with no respiratory symptoms [10], including single cases of isolated attack on the limbic system [20].…”

“…Interestingly, it is possible for para-infectious LE, associated with SARS-CoV-2 to occur in patients with respiratory system involvement, as well as in patients with no respiratory symptoms [10], including single cases of isolated attack on the limbic system [20]. In the majority of described clinical cases, the most common neurological symptoms of this disease were: cognitive impairment; focal and generalized tonic-clonic seizures, including the development of status epilepticus; neuropsychiatric symptoms (olfactory and visual hallucinations, short-term memory loss, anxiety-depressive disorders, socialization problems); and olfactory dysfunction [10,21,23,25,32]. The presence of ictal or (more common) interictal abnormal activity located in the temporal lobe in electroencephalography (EEG) should be considered as a significant factor [13].…”

“…Due to the absence of viral RNA or specific antibodies in cerebrospinal fluid (CSF), it might be the case that damage of the limbic system in COVID-19 patients is primarily associated with the autoimmune response, induced by SARS-CoV-2. Therefore, the nature of this pathological process may be described as para-infectious, and high-field Magnetic Resonance Imaging (MRI) of limbic structures can be considered as an important method of intravital diagnosis of para-infectious LE associated with SARS-CoV-2 [20,21].…”

“…Glutamine (2-aminopentanamide-5-ovic acid) is the 1 of the 20 standard amino acids that make up the protein. An interesting fact is that in most patients with SARS-CoV-2, serological tests on autoimmune panels, including autoantibodies against intracellular, synaptic and surface antigens previously described in LE of a different etiology, were negative [21]. According to this fact, some authors consider the development of SARS-CoV-2-associated para-infectious LE caused by secondary hyperinflammatory syndrome with a massive release of proinflammatory cytokines and chemokines in the limbic system of the brain [21,57,58].…”