[Primary meningococcal arthritis in pediatrics. Report of nine cases].

Primary meningococcal arthritis is an extremely uncommon type of invasive meningococcal disease, with an incidence of 1.5- 1.8% of all paediatric cases of pyogenic arthritis. It is defined as the presence of acute septic arthritis without association with meningitis or the classic meningococcaemia, and isolation of Neisseria meningitidis in synovial fluid and/or blood culture. Typically monoarticular, mostly affects large joints. Prognosis is excellent with appropriated treatment. The aim of this study is to report 9 cases of primary meningococcal arthritis, evaluated at Hospital de Niños "Dr. R. Gutiérrez" in a period of 3 years, and to discuss clinical and epidemiologic issues.