A Case of Concurrent Leukocytosis and Systemic Capillary Leak Syndrome Due to Pegfilgrastim.

Pegfilgrastim is a granulocyte colony-stimulating factor agent used in patients receiving myelosuppressive therapy with chemotherapy or radiation. Two adverse effects associated with this agent include capillary leak syndrome and leukocytosis. To our knowledge, this is the first case of a patient who developed both systemic capillary leak syndrome and leukocytosis greater than 100,000 cells/µL after receiving pegfilgrastim. This patient received early fluid resuscitation, vasopressor support, and methylprednisolone, which improved her clinical course during hospitalization.

Myasthenia Gravis as an Immune-Mediated Side Effect of Checkpoint Inhibitors.

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.