Relapsing Polychondritis and Aseptic Meningoencephalitis.

We herein report a 49-year-old Japanese man with relapsing polychondritis (RP) and aseptic meningoencephalitis. Four years ago, the patient was diagnosed with RP. Prednisolone (PSL) was started at 30 mg/day, and the symptoms promptly disappeared. However, cognitive impairment gradually appeared from six months before hospitalization. Methylprednisolone pulse therapy was immediately initiated, followed by administration of PSL at 1 mg/kg/day. Intravenous cyclophosphamide was combined with PSL. After treatment, the patient's cognitive impairment clearly improved. In conclusion, RP rarely causes aseptic meningoencephalitis, highlighting the need for prompt and aggressive immunosuppressive therapy.