Objective  To explore the clinical features, treatment and prognosis of initial-onset myasthenia gravis (MG) at an advanced age.

Methods  A total of 35 elderly patients with initial-onset MG from April 2009 to December 2020 who underwent MG-associated antibody detection in Zhengzhou University and Henan Institute of Medical and Pharmaceutical Sciences were selected as study subjects. The information of included patients was retrospectively analyzed, and the clinical characteristics and prognosis of elderly patients with elderly-onset MG were observed by literature review.

Results  Of 35 patients, 33 were positive for acetylcholine receptor antibody, of which 12 patients were positive for Titin antibody, 1 patient was positive for muscle-specific kinase antibody, and 1 patient was double negative for serum MG. No patient with positive LDL associated receptor 4 antibody was found. Of 18 patients registered, 13 (72.22%) were initially involved in ocular and 6 (46.15%) developed systemic MG, with a mean diagnosis delay of 5.30 months. The positive rate was 92.31% (12/13) for neostigmine test and 54.55% (6/11) for repeated electrical nerve stimulation (RNS). Chest CT examination results showed that 23.08% (3/13) patients were associated with thymoma, and the incidence of crisis was 16.67%. During the follow-up, 8 patients died, with a fatality rate of 44.44% (8/18).

Conclusion  Most of initial-onset MG patients at advanced age are women positive for acetylcholine receptor antibody. Most of the cases involve the ocular muscle, are often hospitalized due to dysphagia. The incidence of myasthenic crisis and the mortality rate arehigh. However, a good prognosis can be obtained using low-dose prednisone alone or tacrolimus in combination as maintenance therapy in patients with multiple affected muscle groups.