Arthrite septique sans germe identifié

No germ can be identified in nearly 20% of clinically suspected septic arthritis (SA). Some studies show that SA with and without germ identified are the same and should be treated in the same way while others suggest that if the clinical features are the same, the prognosis of SA without an identified germ is better and patients can be given alternative diagnoses. Culture-negative SA may be due to prior antibiotic therapy, a fastidious or non-cultivable bacteria on usual media, or to the fact that the arthritis is not septic. Crystal arthritis is the most common cause of acute arthritis, but it can coexist with SA. Rheumatoid arthritis and spondyloarthritis are the most common causes of pseudoseptic arthritis, but many other rare causes are possible. There is no reliable way to differentiate septic and non-septic arthritis when bacteriological finding is negative. The quality of the bacteriological investigation before any antibiotic therapy remains the best way to limit the frequency of SA without germ identified.