Primary meningococcal polyarthritis.

We report a case of primary meningococcal polyarthritis simulating bacteraemic gonococcal infection. The clinical similarity between extragenital gonococcal and meningococcal infections is well illustrated. If the clinical features of meningococcal and gonococcal infections are usually different, they may sometimes be indistinguishable. Both gonococcal pharyngitis and meningococcal urethritis have been recorded. The onset of acute polyarthritis, fever and skin lesions is typical of gonococcal infection but these clinical features may also indicate infection due to Neisseria meningitidis. In the case we report, the correct diagnosis of meningococcal arthritis was established only after N. meningitidis group C had been identified in synovial fluid from the knee.