Immune Checkpoint Inhibitor-induced Bilateral Vestibulopathy.

Checkpoint inhibitors (CPI), such as anti-programmed death-1 and anti-cytotoxic T-lymphocyte antigen-4antibodies cause serious, rarely fatal immune-related adverse events (irAE) potentially in all organ systems. Neurological immune-related adverse events occur in 1%-5% of patients on CPI therapy and may present with dramatic clinical symptoms of the sensory organs. After exclusion of other causes, a high-dose treatment with corticosteroids is crucial for clinical outcome with lower risk of sequelae. We present a severe case of CPI-related ongoing and most likely irreversible bilateral vestibular affection. A 59-year-old male melanoma patient with brain metastasis undergoing immunotherapy with anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed death-1 antibodies developed severe debilitating rotatory vertigo. Bilateral vestibulopathy was diagnosed as a result of the CPI therapy after a thorough analysis including magnetic resonance imaging, laboratory tests of blood and cerebrospinal fluid as well as neurological and otorhinolaryngology examinations. The vertigo improved slightly during a 10-day course of steroid therapy and intensive balance training but did not resolve completely.