医学课件myasthenia

m yasthenia gravis (MG) l Speaker: Li Xianzhe l Members:Wang Fuhai, Wang Defeng, Guo Xiuquan,Wang Zhuqing,Chen Weiwei,Zhu Youkang,Yuan Mingzhen DEFINITION Myasthenia gravis is an autoimmune disease that affects the transmission of signals from nerves to muscles. l AChR is one kind multifunctional transmembrane 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 cells. communications break down between nerves and muscles. What cause MG? Mechanism of MG u HI u CMI u Abnormal Thymus HI l 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 autoantibodies 3、 Opsonization of Anti-AChR 4、 Others CMI l AChR is a kind of TD-Ag l In MG patients T cells kill the AChR of Thymus and muscles directly. Abnormal Thymus l Immune tolerance is broken by abnormal thymus positive and negative selection Symptoms? Weakness of the eye muscles Change in facial expression Difficulty in swallowing and shortness of breath Weakness in arms, hands, fingers, legs, and neck Treatment Treatment of MG Medications l 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） Thymectomy l 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