[Eosinophilic meningoencephalitis in a case of rheumatoid arthritis]

A 56-year-old man was admitted to our hospital due to gradually developing consciousness disturbance. He had an 11-year history of sero-negative rheumatoid arthritis (Stage III) maintained by daily administration of 10 mg of prednisolone and 300 mg of actarit. On admission, he showed meningeal irritation and a marked increase in eosinophils in his cerebrospinal fulid (CSF) (457/microliter), while eosinophils in his peripheral blood were not increased (0/microliter). Shortly after admission he fell into a coma. Upon measurement in the coma state, his peripheral blood eosinophil count was found to be increased (max: 1742/microliter). Parasitic infection, Angiostrongylus cantonensis in particular, was excluded both by repeated microscopic examination of CSF and by immunological approaches for CSF and serum. Serum examinations showed broad cross-reaction between various parasitic antigens and positive myeloperoxdase-antineutrophil cytoplasmic antibody (18 EU/ml). Three pulses of methylprednisolone (500 mg/day) followed by conventional prednisolone therapy (60 mg/day) was effective for alleviating the signs and symptoms of eosinophilic meningoencephalitis. In this patient, it was considered that the cerebrospinal angiitis resulting in eosinophilic meningoencephalitis had been elicited by immunological abnormalities.