Abstract: Objective　To analyze the clinical manifestations and prognosis of patients with late-onset myasthenia gravis （LOMG）.Methods　Forty-five patients with LOMG undergoing treatment at Weifang People's Hospital，Qianfoshan Hospital of Shandong，and Xuanwu Hospital，Capital Medical University between January 2015 and January 2017 were selected as the study subjects.The patient general information，clinical symptoms，complications，laboratory tests，treatment，and follow-up data were collected and retrospectively analyzed.The clinical data of patients with different ages of onset and prognosis were compared.Results　The 45 LOMG patients included 28 males and 17 females，with an average age of onset of （73.4±9.7） years.The initial symptoms included ocular muscle involvement 〔38 cases （84%）〕，ball palsy 〔31 cases （69%）〕，and difficulty raising the head 〔6 cases （13%）〕.According to the Osserman classification，there were 10 type Ⅰ，27 type Ⅱ，and 8 type Ⅲ early-stage cases，and 7 type Ⅰ，15 type Ⅱ，21 type Ⅲ and 2 type Ⅳ acme-stage cases.Eighteen patients （40%） had myasthenia gravis associated autoimmune dysfunction and 41 patients （91%） had at least one medical complication.Among the 43 patients who underwent AchR-Ab testing，39 （91%） were positive.Among the 33 patients who underwent cholinesterase inhibition testing，31 （94%） were positive.Abnormalities in neuromuscular electrophysiologic examinations existed in 20 （61%） of 33 patients.An increase in 1 or more autoantibodies occurred in 10 patients；there were 7 patients （17%） with abnormal thymus imaging among 42 patients who underwent chest imaging.Forty-two patients （93%） were treated with anti-cholinesterase inhibitors，36 patients （80%） received conventional immunosuppressive therapy，and 10 patients （22%） had thymectomies.The incidence of ball palsy，the Osserman classification in the early stage，and the mortality rate were significantly different among patients with different ages of onset （P<0.05）.The Osserman classification in the acme-stage among patients who died was significantly higher than in survivors.The incidence of cancer and the number of hospitalizations during the follow-up period in the patients who died were also significantly higher than in survivors （P<0.05）.Conclusion　Patients with LOMG have clinical features，such as involvement of laryngeal muscles，diverse clinical manifestations，complications of autoimmune diseases，and poor response to thymectomy.Such patients should be followed closely with early diagnosis and treatment.

Key words: Myasthenia gravis, Signs and symptoms, Prognosis

摘要： 目的　分析晚发型重症肌无力（LOMG）患者的临床特点及预后。方法　选取2015年1月—2017年1月潍坊市人民医院、山东省千佛山医院、首都医科大学宣武医院收治的45例LOMG患者为研究对象，回顾性分析患者的一般情况、首发临床症状及Osserman分型、合并症、实验室检查、治疗及随访情况，比较不同首次发病年龄、预后患者的临床资料。结果　45例LOMG患者，其中男28例，女17例；平均首次发病年龄（73.4±9.7）岁；首发临床表现为眼肌受累38例（84%），球麻痹31例（69%），抬头无力6例（13%）。Osserman分型，发病初期：Ⅰ型10例，Ⅱ型27例，Ⅲ型8例；极期：Ⅰ型7例，Ⅱ型15例，Ⅲ型21例，Ⅳ型2例。18例（40%）患者存在与重症肌无力相关的自身免疫功能障碍，41例（91%）患者至少有1种合并症。43例接受抗乙酰胆碱受体抗体（AchR-Ab）检测患者中39例（91%）阳性，33例接受胆碱酯酶抑制试验患者中31例（94%）阳性，33例接受神经肌肉电生理检查患者中20例（61%）存在异常。10例患者有1种或多种自身抗体水平升高。42例行胸部影像检查患者中7例（17%）显示胸腺异常。42例（93%）患者接受抗胆碱酯酶抑制剂治疗，36例（80%）患者接受常规免疫抑制治疗，10例（22%）患者行胸腺切除术。不同首次发病年龄患者球麻痹发生率、发病初期Osserman分型、病死率比较，差异均有统计学意义（P<0.05）；死亡患者极期Osserman分型高于存活患者，癌症发生率、随访期间住院次数多于存活患者（P<0.05）。结论　LOMG患者具有多个特点：咽喉肌群易受累，表现形式多样，多合并有自身免疫疾病，胸腺切除治疗效果不佳，临床工作中需提高对该病的认识，做到早期诊断和治疗。

关键词: 重症肌无力, 体征和症状, 预后