Can N meningitides cause a septic arthritis?
Acute meningococcemia can cause arthralgias in up to 40% of cases. An acute purulent arthritis can later follow in a minority of cases (2%–10%). It usually involves the knee. Only 25% of patients have associated meningitis. Many will have an associated maculopapular rash. Synovial fluid cultures are positive in 20% and should be kept for 7 days instead of the usual 3 days. PCR testing of synovial fluid may be useful if cultures are negative and suspicion is high. Most patients respond well to antibiotics (third-generation cephalosporin) and joint drainage.