[An adult case of group A streptococcus meningitis associated with steroid-responsive meningoencephalitis].

A previously healthy 80-year-old woman presented to our service in a comatose state. On examination the patient had fever and neck stiffness. Laboratory investigation showed polymorphonuclear pleocytosis in cerebro-spinal fluid (CSF). These findings prompted us to a diagnosis of bacterial or viral meningitis and combination therapy consisting of ceftriaxone, vancomycin and acyclovir was started immediately. Two days later, culture of blood yielded Streptococcus pyogenes (group A streptococcus; GAS). The antibiotic therapy was converted to intravenous ampicillin for 14 days. Fever resolved quickly, however, somnolence persisted. Fluid attenuated inversion recovery image of the brain, taken on the day 29, showed focal hyperintense lesions on the right subcortical area in the temporal and parietal lobes. Three times repeated intravenous steroid pulse therapy (methylprednisolone 1,000 mg/day, 3 days) resulted in complete improvement of her consciousness disturbance. We considered the present case to be a steroid-responsive meningoencephalitis caused by GAS infection.