Primary oligoarthritis in a parent of a child with meningococcal group B sepsis and meningitis.

The mother of an eight-month-old child with meningitis presented with petechiae on her trunk and lower extremities, fever, and oligoarthritis. Although pathogens were never revealed by Gram stain nor cultured from the aspirated joint fluid, the diagnosis was primary meningococcal arthritis. This diagnosis was based on the simultaneous occurrence of Neisseria meningitidis group B infection in her son and the clinical presentation.