Rheumatoid Meningitis with Generalized Convulsions during Peficitinib Treatment, in Which Anti-cyclic Citrullinated Peptide Antibody in the Cerebrospinal Fluid Was Useful for Making a Diagnosis: A Review of the Literature and Previous Reports.

An 80-year-old woman with sudden generalized convulsions was admitted to our hospital. She had a 33-year history of rheumatoid arthritis. Head magnetic resonance imaging (MRI) at the time of admission showed characteristic leptomeningeal findings, and the anti-cyclic citrullinated peptide antibody (ACPA) titer in the cerebrospinal fluid (CSF) was elevated, thus leading to a diagnosis of rheumatoid meningitis (RM). After glucocorticoid treatment, the patient's symptoms promptly improved. RM is often diagnosed using a meningeal biopsy and MRI; however, recent reports have suggested that the CSF ACPA titers (antibody titer index) may also be elevated. In this case, CSF ACPA was useful for making a diagnosis and selecting the optimal treatment modality.