Anti-Cyclic Citrullinated Peptide Antibody-Positive Meningoencephalitis in the Preclinical Period of Rheumatoid Arthritis.

Rheumatoid meningoencephalitis (RM) is a rare complication of rheumatoid arthritis (RA). This report describes a 63-year-old man with complaints of high-grade fever, headache, and vomiting for several days before admission. Both his serum and cerebrospinal fluid were positive for anti-cyclic citrullinated peptide (CCP) antibody and rheumatoid factor, and contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging (MRI) showed abnormal gadolinium enhancement of the meninges and high-intensity lesions in the subarachnoid spaces. The patient was diagnosed with RM despite lack of signs suggesting RA. His symptoms drastically improved with intravenous infusion of high-dose methylprednisolone. Two months later, he developed RA. The findings in this patient suggest that RM could develop prior to the onset of RA. Anti-CCP antibody and MRI findings may be useful for the diagnosis of RM, regardless of RA history.