A case of primary meningococcal conjunctivitis in an older patient.

Primary meningococcal conjunctivitis (PMC) is rare, and it is particularly rare in older patients. Patients with PMC may develop invasive meningococcal disease (IMD), which has an overall mortality rate of 8 %-14 %. An 81-year-old man presented to us with complaints of decreased vision and persistent pain in his right eye after ocular trauma. He had copious purulent discharge, conjunctival injection, corneal edema and Descemet's membrane folds in the right eye. The best-corrected visual acuity (BCVA) was 0.02. Levofloxacin 1.5 % eye drops and fluorometholone 0.1 % eye drops, each four times daily, were initiated before the results of conjunctival culture were available. Neisseria meningitidis was isolated 2 days after the patient's first visit. Cefmenoxime hydrochloride 0.5 % eye drops eight times daily were added and a single dose of oral levofloxacin 500 mg was administered to prevent IMD. After treatment, his symptoms resolved and BCVA increased to 0.8. The frequency of instillation of eye drops was reduced, and all medications were stopped 21 days after the first visit. The patient did not develop IMD. Later, the serogroup and sequence type of our isolate was revealed to be non-groupable and 11026, which is unique to Japan. All ST-11026 isolates have been found to lack the ability to synthesize capsular polysaccharide, which is one of the meningococcal pathogenicity. If a patient presents with conjunctivitis with copious ocular purulent discharge, conjunctival culture should be performed promptly for early diagnosis of PMC regardless of the patient's age.