Monoarthrite du genou à Neisseria meningitidis sans méningite : apport de la culture du liquide articulaire en flacon d’hémoculture

Abstract

Introduction. – Primary meningococcal arthritis is a rare form of meningococcal disease. It occurs as an isolated acute purulent arthritis without meningitis, and presence of Neisseria meningitidis in articular fluid. We report a new case of typical primary meningococcal arthritis. Exegesis. – A previously healthy 23-year-old female patient was admitted for purpuric lesions of the legs. At admission, conscience was normal and symptoms of meningitis were absent. During the 2nd day of hospitalisation, a warm and painful effusion in the right knee appeared. Aspiration from the right knee yielded a purulent fluid. N. meningitidis was isolated from a blood-culture vial inoculated with the synovial fluid, while blood cultures remained sterile. Anti-biotherapy was initiated as soon as microbiological diagnosis was established. The patient was symptom-free 1 month later. Conclusion. – We emphasize the fact that agar cultures of the synovial fluid remained sterile, while N. meningitidis grew in a blood-culture vial. We suggest that diagnosis of primary meningococcal arthritis may be underestimated when inappropriate culture media are used.