Havard C W, Scadding G K
Drugs. 1983 Aug;26(2):174-84. doi: 10.2165/00003495-198326020-00004.
Myasthenia gravis is a disorder of autoimmunity in which neuromuscular transmission is impaired by autoantibodies to the acetylcholine receptor (AChR). There is evidence for more than one form of the disorder with differing genetic susceptibilities. The aetiology is unknown, but thymic involvement is suggested by abnormal histology and by the beneficial response of the disorder to thymectomy in more than two-thirds of patients. Thymectomy is indicated in most patients unless the symptoms are minimal or are confined to the extraocular muscles alone, or the patient is elderly. Thymectomy alone results in remission in about one-third of patients, but, in addition, most patients require symptomatic anticholinesterase drugs to prolong the action of acetylcholine at the muscle end-plate. Over-dosage of these drugs can also cause weakness. Immunosuppression with corticosteroids or azathioprine may also improve myasthenia; at present, these drugs are used mainly in patients who do not respond to thymectomy or in those patients considered unsuitable for operation. Plasma exchange can cause a rapid, though temporary, involvement in myasthenia, but it probably has no long term place in its treatment. Future therapy will probably involve specific immunotherapy, such as anti-idiotype antibodies.
重症肌无力是一种自身免疫性疾病，其中乙酰胆碱受体（AChR）自身抗体损害神经肌肉传递。有证据表明该疾病存在不止一种形式，具有不同的遗传易感性。病因尚不清楚，但组织学异常以及超过三分之二的患者在胸腺切除术后病情得到改善提示胸腺受累。大多数患者需要进行胸腺切除术，除非症状轻微或仅局限于眼外肌，或者患者年龄较大。单独进行胸腺切除术约三分之一的患者病情缓解，但此外，大多数患者需要使用抗胆碱酯酶药物来延长乙酰胆碱在肌肉终板的作用时间。这些药物过量也会导致肌无力。使用皮质类固醇或硫唑嘌呤进行免疫抑制也可能改善重症肌无力；目前，这些药物主要用于对胸腺切除术无反应或被认为不适合手术的患者。血浆置换可迅速（尽管是暂时的）改善重症肌无力，但可能在其治疗中没有长期作用。未来的治疗可能会涉及特异性免疫疗法，如抗独特型抗体。
