Abstract
BACKGROUND: Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that block inhibitory pathways that cancer cells exploit to suppress T-cell activation. Although immune-related adverse events (irAEs) linked to ICI therapy are well documented and encompass dermatologic, endocrine, gastrointestinal, hepatic, and neurologic systems, ICI-related dysautonomia remains a rare phenomenon. Management of ICI-related dysautonomia is undefined. CASE: We report the case of a 57-year-old male patient treated with neoadjuvant nivolumab for Merkel cell carcinoma who developed ICI-related dysautonomia. His dysautonomia was characterized by orthostatic hypotension, urinary retention, hearing loss, and binocular diplopia in addition to the development of ICI-related hepatitis. We describe the patient's course, including the treatment and outcome of his dysautonomia, and review the literature on this rare toxicity. CONCLUSION: Due to the mechanism of action of ICIs, irAEs can present with a wide range of manifestations. In this case, prompt recognition of ICI-induced dysautonomia and timely administration of intravenous immunoglobulin (IVIG) led to significant clinical improvement. ICI-induced dysautonomia is a rare condition that is difficult to diagnose and manage.