Autoimmune movement disorders complicating treatment with immune checkpoint inhibitors

Background: Immune checkpoint inhibitors (ICI) may trigger autoimmune neurological conditions, including movement disorders (MD). Objectives: The aim of this study was to characterize MDs occurring as immune-related adverse events (irAEs) of ICIs. Methods: A systematic literature review of case reports/series of MDs as irAEs of ICIs was performed. Results: Of 5682 eligible papers, 26 articles with 28 patients were included. MDs occur as a rare complication of cancer immunotherapy with heterogeneous clinical presentations and in most cases in association with other irAEs. Inflammatory basal ganglia T2/fluid attenuated inversion recovery abnormalities are rarely observed, but brain imaging is frequently unrevealing. Cerebrospinal fluid findings are frequently suggestive of inflammation. Half of cases are associated with a wide range of autoantibodies. Steroids and ICI withdrawal usually lead to improvement, even though some patients experienced relapses or a severe clinical course. Conclusion: MDs are a rare complication of ICIs that should be promptly recognized to offer patients a correct diagnosis and treatment.