Abstract: Objective:To study the clinical characteristics of eucine-rich glioma-inactivated1protein(LGI1) antibody positive limbic encephalitis (LE), and to provide the reference for its diagnosis and streatment. Methods:The clinical data of a patient with anti-LGI1 antibody positive LE who presented the hypothalamus symptoms was analyzed, the literature review was performed, and the diagnosis and treatment methods of the LE patients were summarized. Results:The patient showed the following symptoms 2 months before hospitalisation,such as sexual dysfunction,overeating, taciturnity, daytime hyposia, intermittent sweating, fever without inducement, hyponatremia, intermittent memory loss and faciobrachial dystonic seizure (FBDS), and the above symptoms progressively exacerbated. After hospitalization,the Mini-Mental State Examination(MMSE)score was 22;the patient could't finish the evaluation of Montreal Cognitive Assessment Scale(MoCA); the serum anti-LGI1 antibody was positive (1:100),and the cerebrospinal fluid anti-LGI1 antibody was positive(1:10). The MRI results showed T1 low signal, T2, Flair high signal, DWI high signal in bilateral hippocampus, amygdala and medial temporal lobe, especially in the right side. The patient was diagnosed as anti-LGI1 antibody positive LE, whose symptoms relieved rapidly after administration of immunoglobulin and steroid therapy. After 6- month-follow-up, the patient recovered completely. Conclusion:The positive results of serum and cerebrospinal fluid anti-LGI1 antibody in the patients combined with the MRI results of head can confirm the diagnosis of anti-LGI1 antibody positive LE. The hypothalamus symptoms, memory loss and FBDS are improved rapidly after immunoglobulin and steroid therapy. The hypothalamic injury possibly exist in the early-stage of anti-LGI1 antibody positive LE.

Key words: limbic encephalitis, hypothalamus, faciobrachial dystonic seizure, leucine-rich glioma-inactivated 1protein