Abstract: Objective　To investigate the clinical，laboratory，imaging and electroencephalogram features，and treatment and follow-up outcome of anti-gamma-aminobutyric acid-B （GABAB） receptor encephalitis，raising clinicians' awareness of this disease.Methods　We collected the clinical data of 12 cases of anti-GABAB receptor encephalitis diagnosed in Department of Neurology of the Second Affiliated Hospital of Zhejiang University School of Medicine and Department of Neurology of Ningbo City Medical Treatment Center Lihuili Hospital from December 2012 to June 2017.We reviewed their clinical，laboratory，imaging and electroencephalogram features and evaluated the treatment effect and outcome by the modified Rankin Scale （mRS）．Results　Of the 12 patients，10 were male and the median age of onset was 56 years（range：47-71）．Seizures were the most common initial manifestations （9 cases）．All patients developed typical symptoms of seizures.Five had small cell lung cancer （SCLC），one had thymoma，and two had suspicion of a tumor.All of them received first-line immunotherapy but only 2 received antitumor treatment.Good outcomes were found in those who were identified with no tumor or those with a detected tumor and received targeted treatment，while poor outcomes were found in those with confirmed or suspected tumor but did not receive antitumor treatment.Conclusion　Anti-GABAB receptor encephalitis is a rare，special type of autoimmune disease，which frequently accompanies tumors.Middle-aged and elderly men with epilepsy，abnormal mental behavior，cognitive impairment and other symptoms of limbic encephalitis as the outstanding performance，should be considered to have this disease.Early identification of this potentially treatable disease can improve patient outcomes.

Key words: Encephalitis, Gamma-aminobutyric acid, Signs and symptoms, Electroencephalography, Therapy, Prognosis

摘要： 目的　探讨抗γ-氨基丁酸B（GABAB）受体脑炎的临床特征、实验室检查、影像学及脑电图表现、治疗和随访情况，提高对该病的认识。方法　回顾性分析2012年12月—2017年6月浙江大学医学院附属第二医院神经内科和宁波市医疗中心李惠利医院神经内科收治的12例诊断为抗GABAB受体脑炎患者的临床资料。收集患者临床特征、实验室检查、影像学及脑电图表现，通过改良Rankin量表（mRS）评估治疗效果及预后。结果　12例患者中男10例，中位发病年龄为56岁（范围为47~71岁）。癫痫发作（9/12）是最常见的首发表现，患者病程中均出现典型的癫痫发作症状。5例患者合并小细胞肺癌（SCLC），1例存在胸腺瘤，2例怀疑肿瘤。患者均接受一线免疫治疗，仅2例接受肿瘤治疗。未发现肿瘤及已对肿瘤行针对性治疗的患者预后相对较好，确诊或怀疑肿瘤而未行肿瘤治疗患者预后较差。结论　抗GABAB受体脑炎是一种罕见的特殊类型自身免疫性疾病，多伴发肿瘤。中老年男性，以癫痫发作、精神行为异常、认知功能障碍等边缘性脑炎症状为突出表现时，需考虑到本病可能。早期识别这一潜在可治性疾病能改善患者预后。

关键词: 自身免疫性脑炎, &gamma, 氨基丁酸, 体征和症状, 脑电描记术, 治疗, 预后