Pembrolizumab Associated Bilateral Optic Neuritis

To report a rare vision threatening side effect of pembrolizumab managed effectively by plasmapheresis.Method: Case report.

A 52-year-old female on Pembrolizumab for vulvar squamous cell carcinoma developed bilateral optic neuritis due to an altered immune system secondary to pembrolizumab targeting her nervous system.

Though brain metastasis and paraneoplastic optic neuropathy are feared complications in cancer patients with vision loss, drug induced bilateral optic neuropathy is a rare possibility and should be considered. As immune checkpoint inhibitors continue to grow in popularity and are approved for more uses, it is important for vigilant monitoring of immune-related adverse events (irAEs) as well as quick and effective management of these adverse reactions. Our patient did not respond to intravenous steroids and subsequent plasmapheresis helped good visual recovery.