Myasthenia gravis syndrome is an autoimmune disease similar to myasthenia gravis. Myasthenia gravis is due to impaired signaling at the neuromuscular junction, the posterior membrane of the nerve synapse. In contrast, myasthenia gravis syndrome is due to a lesion of the presynaptic membrane at the neuromuscular junction, the development of which is primarily thought to be related to malignant tumors. Tumor cells share common antigens with calcium channels in the presynaptic membrane of the nerve, so a cross-immune response is generated, and the immune response that is supposed to be directed against the antigens of the tumor cells causes the calcium channels in the presynaptic membrane of the nerve to be attacked and destroyed. As a result, when nerve signaling reaches the nerve endings, calcium ions cannot enter the cell due to the attack and destruction of calcium ion channels, resulting in a decrease in acetylcholine release, leading to impaired signaling and weak muscle contraction. Myasthenia gravis syndrome is more common in adult males and has a subacute onset with progressively worsening muscle weakness in the proximal extremities and trunk. Myasthenia gravis is mainly characterized by morbid fatigue, generally the lower limbs are heavier than the upper limbs, and often the first clinical manifestation is the patient’s difficulty in walking up stairs, difficulty in standing up in a sitting position, and difficulty in walking, and the symptoms do not get better after resting, and the muscles of the face and the throat are not involved, so the symptoms of difficulty in swallowing and slurred speech are less common in clinical practice.