Rheumatoid meningitis sine arthritis: An emerging cause of isolated pachymeningitis and leptomeningitis with typical features

Abstract

Background and purpose: Rheumatoid meningitis (RM) is a meningeal inflammation rarely occurring during the course of rheumatoid arthritis (RA). Anti-citrullinated protein antibodies (ACPA), which are highly specific biomarkers of RA, may allow RM sine arthritis (RMSA) to be diagnosed as an extra-articular early lesion of RA. MRI typically displays pachymeningitis and/or leptomeningitis predating convexity, and CSF diffusivity is focally restricted. Blood ACPA is a strong clue and intrathecal synthesis of ACPA is characteristic although rarely reported. Methods: We report two cases of RMSA that were confirmed by meningeal biopsy and intrathecal synthesis. Results: RMSA abated after steroids alone or associated with rituximab. No arthritis occurred during the follow-up. Conclusion: RM can occur in the absence of RA.

Keywords

• Rheumatoid arthritis
• Rheumatoid meningitis
• Pachymeningitis
• Leptomeningitis
• Diffusion