Meningococcal meningitis with meningococcemia: a rare sporadic case in an elderly patient with no history of contact with infected individuals.

An 89-year-old Japanese woman with no history of contact with infected individuals developed meningococcal meningitis with meningococcemia. Compared with other countries, invasive meningococcal disease is relatively rare in Japan, with an annual incidence of a total of 10-20 cases for more than 2 decades; this represents approximately 1% of the corresponding incidence in the United States and United Kingdom. The most prevalent serotypes of the causative agent Neisseria meningitidis in Japan are serotypes B and Y. The patient in this study was also infected with a strain of serotype Y. The meningococcal vaccine has not yet been approved for use in Japan. The only possible transmission route in this patient was a visit by the patient's grandchild a few days prior to the onset of symptoms. Due to its low incidence, clinicians do not have sufficient experience for managing this potentially fatal illness. This case highlights the need for considering a complete differential diagnosis of invasive meningococcal disease.