A systematic review of myasthenia gravis complicated with myocarditis

Among many of the autoimmune diseases observed in patients with myasthenia gravis (MG), myocarditis is one of the most critical. The goal of this review is to systematically describe and investigate the characteristics of MG complicated with myocarditis. We identified 183 records in PubMed (MEDLINE), Web of Science, and EMBASE from 1948 to September 10, 2020. Studies were included if they presented clinical data on MG complicated with myocarditis. Of the 35 patients from 28 studies in this review, 57.14% (20/35) were males, with a mean age of 59.11 ± 15.87. Dyspnea was the most common cardiac symptom accounting for over 60% in the study. Among the 35 patients, 13 cases of myocarditis occurred concomitantly with MG and the longest interval between MG and myocarditis was 7 years. Forty percent of patients developed myocarditis caused by immune checkpoint inhibitors (ICI). Among the patients with myocarditis, over half of the patients were diagnosed by myocardial biopsy. After active immune regulation and symptomatic treatment, only 15 of 35 patients with MG complicated with myocarditis improved, 18 patients died during hospitalization, one patient died due to tumor progression and 1patient died 5 years later. The prognosis of patients with MG complicated with myocarditis is poor, and myocardial enzymes and other indexes need to be monitored for patients taking ICI drugs. Patients with dyspnea who are still not ideally treated by mechanical ventilation should be vigilant against the occurrence of MG complicated with myocarditis.