[A case of possible elderly onset rheumatoid meningitis without arthritis].

A 93-year-old man was admitted to our hospital with disturbance of consciousness. Brain magnetic resonance imaging (MRI) showed hyperintensity of the subarachnoid space in the left frontal and parietal lobes on diffusion weighted imaging (DWI) and fluid attenuated inversion recovery (FLAIR). Gadolinium-enhancement of the pia mater was also observed. We did not perform biopsy because of a high risk of perioperative complication. Although physical examination found no evidence of the rheumatoid arthritis, rheumatoid factors and anti-cyclic citrullinated peptides antibodies were elevated. He was suspected to have rheumatoid meningitis. We treated him with intravenous methylprednisolone (0.5 g/day) for 3 days. Rheumatoid meningitis often shows hyperintensity of the subarachnoid space on the DWI and FLAIR, and steroid therapy is effective.