Rinsho Shinkeigaku (Clinical Neurology)

Case Report

A case of myasthenia gravis and myositis induced by pembrolizumab

Tomoko Noda, M.D., Ph.D.1), Haruka Kageyama, Ph.D.1), Miki Miura, Ph.D.1), Takuya Tamura, M.D., Ph.D.1) and Hiroki Ito, M.D., Ph.D.1)

1)Department of Neurology, Ichinomiya Municipal Hospital

A 77-year-old woman with lung adenocarcinoma noticed bilateral ptosis 7 weeks after a first pembrolizumab infusion. Her symptoms rapidly progressed to generalized manifestations including limb and neck weakness, dyspnea, and dysphasia within the following two weeks. We diagnosed him with pembrolizumab-related myasthenia gravis and myositis based on clinical symptoms, elevation of muscle enzymes and anti-acetylcholine receptor antibodies, repetitive nerve stimulation and muscle biopsy. We commenced combination immunotherapy, including intravenous and oral steroid therapy, immune absorption therapy and plasma exchange therapy with noninvasive positive-pressure ventilation and tracheotomy positive pressure ventilation. She had gradual symptoms improvement and discharged after 209 days in a hospital. In this case, anti-titin antibodies, one of anti-striational antibodies, was positive and correlated with severity of myasthenia gravis. With the development of immune checkpoint inhibitors for various malignancies, clinicians should closely monitor patients for important immune-related adverse events and coordinate on early treatment.
Full Text of this Article in Japanese PDF (864K)

(CLINICA NEUROL, 59: 502|508, 2019)
key words: pembrolizumab, immune checkpoint inhibitor, myasthenia gravis, myositis, anti-titin antibody

(Received: 18-Nov-18)