1、 m yastheniagravis(MG)l Speaker: Li Xianzhel Members:Wang Fuhai, Wang Defeng, Guo Xiuquan,Wang Zhuqing,Chen Weiwei,Zhu Youkang,Yuan MingzhenDEFINITIONMyasthenia gravis is an autoimmune disease that affects the transmission of signals from nerves to muscles. l AChR is one kind multifunctional transme
2、mbrane glycoprotein , be composed of 5 subunits, sub alpha unit among them is the main antigen that binds with anti-AchR . Sub alpha unit of AchR is also antigen determinant that binds with T munications break down between nerves and muscles. What cause MG?Mechanism of MGu HI u CMIu Abnormal ThymusH
3、Il 1.antibodies block or destroy many receptor sites for acetylcholine in muscles.2.Destruction of the muscle membrane as a result of complement activation by autoantibodies3、 Opsonization of Anti-AChR 4、 OthersCMIl AChR is a kind of TD-Agl In MG patients T cells kill the AChR of Thymus and muscles
4、directly.Abnormal Thymusl Immune tolerance is broken by abnormal thymus positive and negative selectionSymptoms? Weakness of the eye muscles Change in facial expression Difficulty in swallowing and shortness of breath Weakness in arms, hands, fingers, legs, and neckTreatmentTreatment of MGMedication
5、sl cholinesterase inhibitors such as neostigmine(新斯的明 ) and pyridostigmine(吡啶斯的明 ). l Immunosuppressive drugs such as prednisone（ 强的松） cyclosporine(环孢菌素 ), and azathioprine（ 硫唑嘌呤） Thymectomyl the surgical removal of the thymus gland (abnormal in most persons with MG). l Plasmapheresis or plasma exchange. l High-dose intravenous immune globulin. l 王军，男， 45岁， 2000年患甲亢，随后出现眼睑下垂，一直以来当作甲亢症状治疗，经过治疗，甲亢的其他症状消失，检查也正常，但眼部症状却未能缓解。患者于 2001年出现复视，挣眼无力，劳累后加重，一次偶然的机会，他从网上发现，他眼睛的症状与重症肌无力的首发症状很相似，他立即上当地医院检查，果然诊断为眼肌型重症肌无力，睑裂明显减小，在采用嗅化吡啶斯的明治疗后病情有所好转，但一感冒病情就加重，继而出现了胸闷气短、双上肢抬举费力，腰膝酸软等症状。
