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Título

Anti-LGI1 encephalitis: a case series from Brazil

Resumo

Introduction Anti-LGI1 antibody causes an autoimmune encephalitis characterized by seizures of variable types, cognitive impairment, limbic encephalitis, and rarely Morvan syndrome. Faciobrachial dystonic seizures (FBDS) are the hallmark of the disease, occurring in 47% of cases. Anti-LGI1 encephalitis is more common in men, is rarely paraneoplastic, and responds well to steroids. Data from developing countries are lacking. Objective To describe epidemiologic and clinical features of a case series of anti-LGI1 encephalitis Methods We reviewed charts of patients with anti-LGI1 antibodies from BrAIN (Brazilian Autoimmune Encephalitis Network) database from 2017 to 2022. Information on clinical, epidemiological, and treatment features was compiled. Results Of the 130 patients with AIE, we found 13 (10%) patients with anti-LGI1 antibodies. Most were female (n=9, 65%), with a mean age of 61,9 ± 13,2 years. Two patients had myasthenia gravis (MG), thymoma, and developed Morvan syndrome with anti-CASPR2 antibodies; one had breast cancer. All the patients met the criteria for possible autoimmune encephalitis, with 2 patients with criteria for limbic encephalitis (15%). The most frequent symptoms were behavioural changes (n=13, 100%), epilepsy (76%, n=10), memory disturbances (69%, n=9), impaired level of consciousness (38%, n=5), language disturbances (23%, n=3) and autonomic stability (15%, n=2). Reported abnormal facial movements were: FBDS (n=3, 23%), and other types in 4 (30%) including tremor, myokymia, and dyskinesia. We observed variable taxonomy in describing Morvan Syndrome and abnormal facial movements. Pleocytosis was found in 3 (23%) patients and abnormal EEG findings in 12 (92%). Approximately 92% had abnormal MRI, and of those 53% (n=7) with mesial temporal T2/FLAIR hyperintensities – 4 of them with this finding happened bilaterally. Conclusions We report variable findings amongst Brazilian patients with anti-LGI1 encephalitis: they were more commonly female, older, and with a higher frequency of abnormal CSF when compared to prior series. We found limbic encephalitis phenotype in only 15%, and prior reports indicate 90%. Patients with Morvan syndrome and thymoma may harbour anti-LGI1 antibodies. Although our data need to be confirmed in larger Brazilian cohorts, our findings may indicate the occurrence of genetic variability in the disease. Nevertheless, our results indicate the need for neurology training in recognizing anti-LGI1 encephalitis.

Palavras Chave

autoimmune encephalitis; anti-LGI1