Cases Reports Of Anti-GABAb Receptor Autoimmune Encephalitis And Literature Review

Background and objectives : Recent fingdings of autoimmune encephalitis with antibodies targeting cell membrane antigens or synaptic protein has led to a new understanding of the clinical features and etiology of autoimmune encephalitis. Anti-gamma-aminobutyric acid-B receptor( GABAb R) encephalitis is a kind of autoimmune encephalitis with several characteristics: typical clinical features of limbic encephalitis, positive antibody targeting GABAb R,good response to immunotherapy. Though early diagnosis and treatment would be beneficial to the patients, there are few cases reported in China. To emphasizing the understanding of this autoimmune encephalitis, three cases of anti-GABAb R encephalitis are reported and related articles are reviewed.Cases presentation : Three male patients were admitted with newly onset seizures, psychosis and memory disorder. The physical examination were normal with exceptions of recognition disorders. The results of screening for infection and tumors were negative. Two of three patients got lesions in one or both temporal lobe in brain MRI and the last one got normal results. All three patients’ serum or cerebral spinal fluid, or both were positive for anti-GABAb receptor antibody testing. Therefore they were diagnosed with anti-GABAb receptor encephalitis. Two patients who received immunotherapy got complete or partial improvement.Conclusion: The diagnosis as anti-GABAb receptor encephalitis of the three patients described here was certain. Anti-GABAb receptor encephalitis belongs to autoimmune encephalitis with manifestations of limbic encephalitis. Middle aged or older were vulnerable to this encephalitis. Additionally approximately 50% of all patients had small cell lung cancer. Currently the diagnosis of this encephalitis depended on the combination of clinical features and antibody testing. Most patients respond well to immunotherapy. First-line treatments are glucocorticoid, immunoglobin and plasmapheresis followed by second-line treatment that consist of rituximab and cyclophosphamide.