Pembrolizumab-Induced Myasthenia Gravis and Myositis: Literature Review on Neurological Toxicities of Programmed Death Protein 1 Inhibitors

We present herein the case of an elderly male patient, who was receiving immunotherapy for his urothelial cancer and who presented to our facility with lower extremity weakness. The patient was diagnosed with myasthenia gravis, thyroiditis, myositis and myocarditis, which were considered as immune adverse events of pembrolizumab therapy. The patient received pyridostigmine, intravenous immunoglobulin, plasmapheresis, corticosteroids, and rituximab with mild improvement of his symptoms. The patient had some neurological recovery, was discharged to a nursing facility, however he was ventilator dependent. Of importance, our case is followed by review and discussion of the literature related to immunotherapy and its side effects.