Anti-Sulfatide Antibody-Positive Neuropathy Following Sintilimab Treatment for Cholangiocarcinoma: A Case Report

Objective: To investigate the clinical characteristics of and management strategies for neurological immune-related adverse events (nirAEs) associated with immune checkpoint inhibitors (ICIs). Methods: We present the clinical course of a 78-year-old man with cholangiocarcinoma who developed polyneuropathy following treatment with the PD-1 inhibitor sintilimab. Clinical features, diagnostic findings, and therapeutic interventions are analyzed alongside a literature review. Results: Approximately three weeks after initiating therapy, the patient developed fever, pain, and numbness in both lower limbs, and diplopia. Multiple cranial nerves were subsequently affected. Cerebrospinal fluid analysis revealed albuminocytologic dissociation, and neurophysiological studies demonstrated slowed motor and sensory nerve conduction in both lower limbs. Symptoms gradually improved following intravenous human immunoglobulin and moderate-dose methylprednisolone therapy. At the three-month follow-up, only mild left-sided facial paralysis remained. Conclusion: PD-1 inhibitors can induce rare but potentially severe polyneuropathy characterized by diverse clinical manifestations and rapid progression. Early recognition and timely immunomodulatory treatment are essential for improving outcomes. However, this single case highlights the need for further studies to clarify the mechanisms and optimize management strategies.