目的　探讨门诊长期使用醋酸泼尼松治疗小儿重症肌无力 (MG)的有效性、安全性和使用方法。方法　对 5 0 4例使用泼尼松“中剂量冲击、小剂量维持”口服疗法的MG患儿进行前瞻性研究 ,观察泼尼松使用剂量、撤药方式与疗效和副反应的关系 ,并分析MG类型、发病年龄、病程及伴发病对疗效的影响。结果　追踪 1～ 16年 (平均 5 5年 ) ,总有效率 95 0 %。终点的疗效与临床类型、发病年龄、病程及是否合并胸腺瘤或胸腺增生无明显关连。 195例患儿按计划撤药 ,其中 70例 (35 9% )症状复发 (药物依赖 )。主要副反应为Cushing反应和易患上呼吸道感染。结论　泼尼松可用于所有类型MG患儿的长期治疗。Cushing反应随药物减量逐渐消失 ,但易患上呼吸道感染和体格矮小不容忽视。药物依赖的发生率很高 ,自制中成药扶正强筋片对此有一定帮助 Objective To investigate the effectiveness, safety and usage of long-term prednisone acetate in the treatment of pediatric myasthenia gravis (MG). Methods A prospective study was conducted in 504 cases of MG patients treated with prednisone “moderate dose shock and low dose maintenance” oral therapy. The relationship between dose, withdrawal mode, curative effect and side effects of prednisone was observed and analyzed Effect of MG type, age of onset, course of disease and complication on curative effect. The results were followed up for 1 ~ 16 years (average 55 years) with a total effective rate of 95%. End-point efficacy and clinical type, age of onset, duration and whether the merger thymoma or thymus hyperplasia no significant correlation. Of the 195 children who were scheduled for withdrawal, 70 (35.9%) had a relapse (drug dependence). The main side effects of Cushing reaction and susceptible upper respiratory tract infection. Conclusion Prednisone can be used for long-term treatment in all types of MG. Cushing reaction with the gradual disappearance of drug reduction, but susceptible to upper respiratory tract infections and short stature can not be ignored. The incidence of drug dependence is very high, homemade proprietary Chinese medicine is strong gluten tablets have some help