Immune checkpoint inhibitor-induced neurologic toxicity: a case report and literature review

Immune checkpoint inhibitors (ICIs) are approved for the treatment of head and neck carcinoma. They have significantly improved survival in these patients but may cause immune-related adverse events (irAEs), some of which may be serious. The report presents a rare case of a neurologic adverse event associated with programmed death-1 inhibitor monotherapy. Neurologic irAEs (NirAEs) can occur in various and atypical forms, be potentially disabling and occur at various times during and after treatment. Prompt identification and drug withdrawal are essential to improve outcomes. A high dose of systemic corticosteroid has been recommended for the management of NirAEs, although optimal immunomodulatory treatment is still debated.Plain language summary Current recommendations for head and neck squamous cell carcinoma treatments have been significantly modified after the introduction of immunotherapy. Indeed, immune checkpoint inhibitors (ICIs) are now recommended in localized and metastatic disease. Programmed death ligand-1 (PD-L1)-positive tumors can be treated with immunotherapy in the first and second lines regardless of PD-L1 expression. By increasing immune system activity, ICIs can have adverse effects. In most cases, these can be treated with the interruption of treatment and/or supportive therapy, which can include the administration of immunosuppressants. This report describes a case of suspected a neurologic adverse event characterized by trouble with balance and double vision in a person with head and neck cancer treated with nivolumab. This was adverse event was by pausing therapy and low-dose steroid treatment, leading to complete reduction of symptoms. Unfortunately, the laboratory and instrumental investigations could not determine an exact diagnosis or the area of neurological damage.