Clinical characteristics of four cases of myositis,myocarditis and myasthenia gravis overlap syndrome induced by immune checkpoint inhibitors

LI Xiao; ZHANG Yan-hua

doi:10.20251/j.cnki.1003-3734.2025.23.015

Abstract：Objective:To summarize and analyze the clinical features,diagnosis,treatment and prognosis of patients with myositis,myocarditis and myasthenia gravis overlap syndrome caused by immune checkpoint inhibitors,in order to provide a reference for the diagnosis and treatment of this adverse reaction.Methods:The clinical data of four patients with overlap syndrome of myositis,myocarditis and myasthenia gravis caused by immune checkpoint inhibitors admitted to our hospital from January 2023 to June 2024 were collected,and the characteristics,clinical manifestations,auxiliary examination results,treatment methods,and outcomes were analyzed and summarized.Results:Among the four patients,three were female and one was male,and the ages at diagnosis were 56～69 years.The syndrome appeared immediately after receiving PD-1 inhibitors or PD-1/CTLA-4 bispecial antibodies for the first course,and the median time was 16.5 days.The main clinical symptoms were fatigue,myalgia,drooping eyelids,restricted mouth opening,and impaired speech.The ECG showed sinus hyperrhythmia with different degree of conduction block.All the four patients received high doses of glucocorticoids and brompyristine,and three of them were treated with gammaglobulin,one was treated with tofaciib simultaneously,the other was treated with plasma exchange and morpheolate,and one patient had a temporary pacemaker placed.All the four patients were discharged from hospital after significant improvement of symptoms,and ICls therapy was not restarted.Conclusion:Myositis,myocarditis,and myasthenia gravis overlap syndrome are serious adverse reactions of ICIs treatment.High-dose glucocorticoids are still the primary treatment,and early combination of immunoglobulin may be beneficial for symptom improvement.Early diagnosis through multidisciplinary cooperation model and necessary life support may provide a good prognosis.