SHM Converge Scientific Abstract ePoster Gallery-Immune Checkpoint Inhibitor-Induced Myocarditis, Myositis, and Myasthenia Gravis Overlap Syndrome

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This case report describes a 76-year-old woman with metastatic melanoma who developed a life-threatening immune checkpoint inhibitor (ICI) toxicity syndrome after her first infusion of nivolumab and relatlimab. About three weeks later, she presented with 2 weeks of progressive myalgias, weakness, diplopia, and dyspnea, along with severe hypoxemia and exam findings of bilateral ptosis and abducens nerve palsy.<br /><br />Laboratory studies showed marked muscle and cardiac injury, including CK 8,494 U/L and high-sensitivity troponin peaking at 1,995 ng/L, plus elevated liver enzymes and LDH. Her echocardiogram was normal with preserved ejection fraction, and CT chest/head were unrevealing. EMG showed myopathic changes without evidence of neuromuscular transmission disorder. Autoimmune testing, including acetylcholine receptor and MuSK antibodies, was negative.<br /><br />She was diagnosed with the rare “triple M” overlap syndrome: ICI-induced myocarditis, myositis, and myasthenia gravis. Her course deteriorated quickly with worsening respiratory failure, requiring ICU transfer, intubation based on low negative inspiratory force and vital capacity, and later tracheostomy. She ultimately improved enough for tracheostomy decannulation but had a prolonged, complicated hospitalization including MRSA ventilator-associated pneumonia, perforated diverticulitis requiring surgery, upper GI bleeding, and another brief intubation after aspiration.<br /><br />The report emphasizes that ICI-related myocarditis has high mortality and may occur together with myositis and myasthenia gravis. Early recognition is critical, especially because respiratory failure is a feared complication. Recommended management includes prompt high-dose IV corticosteroids, early IVIG or plasmapheresis when MG is suspected, and additional immunosuppressive agents in refractory or severe cases. The authors stress the need for multidisciplinary care and close monitoring of respiratory function.

Asset Subtitle

Daria Seriak

Meta Tag

Author List Daria Seriak, Matthew Basciotta

Category Clinical Vignettes

Concept Immune Checkpoint Inhibitor

Concept Myocarditis

Concept Myositis

Concept Myasthenia Gravis

Concept Corticosteroids

Distinguished Non-Finalist

Presenter Organization Mass General Brigham-Salem Hospital

Presenting Author Daria Seriak

Track Adult

Keywords

metastatic melanoma

nivolumab

relatlimab

immune checkpoint inhibitor toxicity

myocarditis

myositis

myasthenia gravis

triple M overlap syndrome

respiratory failure

high-dose corticosteroids

Immune Checkpoint Inhibitor

Myocarditis

Myositis

Myasthenia Gravis

Corticosteroids