Antileucine-rich Glioma-inactivated 1 Autoimmune Encephalitis: A Case Report And Literature Review

Objective: Autoimmune encephalitis(AE)is a non-infectious encephalitis caused by the antigen-antibody reaction of the autoimmune system to the central nervous system antigen.Anti-leucine-rich glioma-inactivated 1(LGI1)antibody associated encephalitis is mediated by the cell surface antibody LGI1 antibody.The prevalence and diagnosis rate of LGI1 antibody encephalitis is relatively low,which is in the stage of clinical case report.Therefore,we discussed the clinical features,treatment plan and outcome of LGI1 antibody encephalitis,and reviewed the literature.Methods: Selecting the data of the patient who had LGI1 antibody encephalitis and hospitalized in Neurology Deparment of the Third Hospital of Hebei Medical University in the year of 2019.At the same time,we consult relevant literatures at home and abroad and summarize the pathogenesis,clinical characteristics and therapeutic method,which provide assistance for diagnosis,treatment and prognostic evaluation of LGI1 antibody encephalitis.Results: The patient was a 59-year-old male.The onset form of the patient was subacute and the progression was aggravated.The main clinical presentations of the patient were faciobrachial dystonic seizure(FBDS),hypomnesis and refractory hyponatremia.MRI of the brain showed high signal of T2 and FLAIR in bilateral basal ganglia.The LGI1 antibody was positive in the patient’s serum and cerebrospinal fluid.The patient was clearly diagnosed with LGI1 antibody encephalitis,and immunotherapy such as glucocorticoid and intravenous injection of immunoglobulin was effective.But the disease recurred during the hormone reduction process,and the patient’s condition improved after the addition of cyclophosphamide.The prognosis was good,but FBDS episodes occurred occasionally.Conclusions: LGI1 antibody encephalitis is one type of autoimmune encephalitis,and common in the elderly male patients,and the specific pathogenesis is not yet clear.Patients with acute or subacute onset of disease,disease progression aggravated.Patients present with one or more of the typical symptoms of limbic encephalitis(seizures,hypomnesis,and psychosocial abnormalities),characterized by FBDS and refractory hyponatremia.Brain MRI of patients show unilateral or bilateral abnormal signals in the medial temporal lobe,hippocampus,or basal ganglia.FDG-PET show hypermetabolism in the medial temporal lobe and basal ganglia.The EEG of patients show no specificity.Diagnosis of the disease depends on serum and/or cerebrospinal fluid tests for LGI1 autoantibodies,but antibody tests may be false-negative and should be repeated.Early intervention and application of immunomodulatory therapy have remarkable effects.The overall prognosis is good,but patients are at risk for recurrence.