Fluctuating weakness affecting the ocular, bulbar, and/or appendicular muscles is characteristic of myasthenia gravis. Autoimmune components and certain drugs have been implicated in the pathophysiology of this disease. I report a case of chronic migraine in which the patient developed symptoms of myasthenia gravis after using galcanezumab, the recently approved anti-calcitonin gene-related peptide (anti-CGRP). This case shows that anti-CGRP medications could affect the neuromuscular junction and cause such symptoms. Moreover, this case illustrates the clinical approach and management of such a presentation.

This is a case report of new-onset myasthenia gravis (MG) as an immune-mediated adverse event (irAE) related to the use of pembrolizumab in a patient with undifferentiated adenocarcinoma of the pancreato-biliary tract. Up to this moment, only 52 cases of new-onset MG have been related to immune checkpoint inhibitors (ICIs). She was diagnosed with ocular MG nearly three months after starting the use of the anti-programmed death-ligand 1 (PD-1) inhibitor. The diagnosis was confirmed by the presence of serum antibodies against the acetylcholine receptor and the patient was started on pyridostigmine with subsequent clinical improvement. The use of pembrolizumab was discontinued due to concomitant progression of the subjacent malignant disease.