The co-occurrence of myasthenia gravis (MG), inflammatory myopathy (IM), and fulminant myocarditis (FM) has rarely been reported. The few previous articles were mostly case reports or small sample data analysis, and the etiology was mostly attributed to thymoma and/or the application of immune checkpoint inhibitors (ICIs).
We report a 74-year-old woman with an acute onset of general weakness, chest tightness, shortness of breath, dysarthria, masticatory weakness and dysphagia, without myalgia or rash. Acetylcholine receptor antibody was positive.
Serum creatine kinase, transaminase, and myoglobin were higher than normal. A variety of autoimmune antibodies including anti-Ro-52, JO-1, nRNP and dsDNA antibodies were positive.
Chest CT showed no thymoma, bronchiectasis with infection in both lungs. Some of them showed interstitial changes.
Electromyography repetitive nerve stimulation of the bilateral deltoid muscle demonstrated a decremental response at low frequencies without an incremental response at high frequencies. Needle electromyography revealed spontaneous potentials.
Echocardiography showed that left ventricular wall motion was generally reduced, left ventricular systolic function was reduced, and cardiac function was EF18%. Muscle biopsy suggested myogenic injury.
Frontiers in Immunology published a clinical update in Infectious Disease on 01 Apr 2026.
The item focuses on Case report: Efgartigimod combined with intravenous methylprednisolone in a case of co-occurrence of unexplained myasthenia gravis, inflammatory myopathy, and fulminant myocarditis.
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