1、重症肌无力临床表现：

①受累骨骼肌病态疲劳：肌肉连续收缩后出现严重无力甚至瘫痪，休息后症状减轻。一般为晨轻暮重。

②受累肌分布和表现具有一定特征：全身骨骼肌均可受累，多以脑神经支配的肌肉最先受累，首发症状常为一侧或双侧眼外肌无力，但瞳孔括约肌不受累。四肢肌肉受累以近端为重，腱反射和感觉正常。

③病程：缓慢或亚急性起病，可因受凉、劳累后突然加重，具有波动性。

④重症肌无力危象：呼吸肌受累，出现咳嗽无力甚至呼吸困难，病情危急，是致死的主要原因。

2、肌无力危象的分类及处理：

①肌无力危象：注射新斯的明或滕喜龙。

②胆碱能危象：立即停用抗胆碱酯酶药物，待药物排除后重新调整剂量。

③反拗危象：停用抗胆碱酯酶药，对气管插管或切开患者采用大剂量类固醇激素治疗，待运动终板功能恢复后重新调整抗胆碱酯酶药物剂量。

所有危象都要注意保持呼吸道通畅，早期处理无好转者立即行气管插管或气管切开；停用抗胆碱酯酶药物；选用足量、有效和对神经-肌肉接头无阻滞作用的抗生素积极控制肺部感染；静注大剂量皮质类固醇激素或丙种球蛋白；必要时行血浆置换。

1. Clinical manifestations of myasthenia gravis:
① Pathological fatigue of affected skeletal muscle: severe weakness or even paralysis occurs after continuous muscle contraction, and the symptoms are relieved after rest. Generally, it is light in the morning and heavy in the evening.
② The distribution and performance of the affected muscles have certain characteristics: the skeletal muscles of the whole body can be affected, most of which are affected first by the muscles innervated by the brain. The first symptom is often unilateral or bilateral extraocular muscle weakness, but the pupil sphincter is not affected. The muscles of the extremities were heavily involved in the proximal end, and the tendon reflex and sensation were normal.
③ Course of disease: slow or subacute onset, which can suddenly aggravate after cold and fatigue, with fluctuation.
④ Myasthenia gravis crisis: respiratory muscle involvement, cough weakness or even dyspnea, critical condition, is the main cause of death.
2. Classification and treatment of myasthenia crisis:
① Myasthenia crisis: inject neostigmine or tengxilong.
② Cholinergic crisis: stop the anticholinesterase drugs immediately and readjust the dose after the drugs are eliminated.
③ Anticonvulsant crisis: stop anticholinesterase drugs, use high-dose steroid hormone treatment for patients with endotracheal intubation or incision, and readjust the dose of anticholinesterase drugs after the function of motor end plate recovers.
Attention should be paid to keep the respiratory tract unobstructed in all crises. If there is no improvement in early treatment, endotracheal intubation or tracheotomy should be performed immediately; Discontinuation of anticholinesterase drugs; Select sufficient and effective antibiotics without blocking effect on nerve muscle junction to actively control pulmonary infection; Intravenous injection of high-dose corticosteroids or gamma globulin; Plasma exchange was performed when necessary.