Myasthenia gravis is a type of autoimmune disease of the nervous system, mainly caused by the production of abnormal antibodies in the body. These antibodies affect the acetylcholine receptors in the postsynaptic membrane, thereby impacting the transmission of nerve impulses at the neuromuscular junction. Being an autoimmune disease, myasthenia gravis usually coincides with the following conditions: The first major category is thymus diseases, with most patients experiencing thymic hyperplasia, and particularly, there may be cases of thymoma. If there is a thymoma, it is advised to undergo surgical treatment promptly. The second major category may involve hyperthyroidism, so it is essential to test thyroid function. Thirdly, some patients may also test positive for antinuclear antibodies, which requires careful differential diagnosis.