Title: 2757 Case report: focal seizure secondary to immune checkpoint inhibitor-induced autoimmune encephalitis
Abstract:<h3>Background</h3> Immune checkpoint inhibitors (ICI) are a new class of therapy used to treat many advanced malignancies. There is increased recognition of rare and severe neurological immune-relate...<h3>Background</h3> Immune checkpoint inhibitors (ICI) are a new class of therapy used to treat many advanced malignancies. There is increased recognition of rare and severe neurological immune-related adverse events(irAEs) related to ICI treatment, such as autoimmune encephalitis (AE). Seizure is one of the common manifestations of AE. <h3>Case Description</h3> A 72-year-old man presented with new onset of refractory focal motor seizures despite treatment with levetiracetam, phenytoin and clobazam. This is on a background of advanced mesothelioma, which he was treated with 3 cycles of ipilimumab and nivolumab with good partial response. CSF studies had shown negative infection screen, and negative anti-neuronal and limbic encephalitis antibodies. MRI Brain had shown multifocal bilateral cortical and subcortical FLAIR hyperintensity, most in keeping with AE. Patient was treated with IV immunoglobulin (IVIg) and IV methylprednisolone (IVMP) with excellent response. He was discharged on anti-seizure medications(ASM) and tapering dose of prednisolone. ICI therapy was ceased due to the severe irAE. Four months later, patient had recurrent seizures. Repeat MRI Brain had shown FLAIR hyperintensity in the right occipital/parietal lobes with resolution of most previous lesions. He was re-loaded with IVIg and IVMP with cessation of seizures. He was discharged on weaning dose of prednisolone, maintenance IVIg, mycophenolate, and ASM. Ten months after cessation of immunotherapy, patient's mesothelioma continued to be stable. <h3>Conclusion</h3> This case highlights the important role of immunotherapy in treating focal seizure secondary to ICI-induced AE. Interestingly, cessation of ICI therapy did not lead to tumor progression at 1 year follow-up in this case.Read More