[Significance of clinically latent bacterial arthritis]

The classical septic bacterial arthritis is a rare event, but can be distinguished by unequivocal signs such as fibrin exudation and neutrophilic masses (pus). For a long time we have been observing an abortive form of bacterial arthritis in biopsies which subsides spontaneously without antibiotic intervention. Only very early during the course can Staphyolcoccus aureus or epidermidis be detected. Despite the brief presence of bacteria, enzymes from the neutrophils can destroy cartilage and bone. The fact that the attending physician had suspected a bacterial infection in only 7% of these patients highlights the diagnostic complexity. We have termed this form clinically latent bacterial arthritis (CLBA). Structural changes in the synovial membrane, e.g. in rheumatoid arthritis or osteoarthritis, predispose for a hematogenous seeding of endogenous staphylococci and trigger clinically unapparent, temporary infections. This clinically latent bacterial superinfection (CLSI) is also self-limiting, but the high degrading potential of the neutrophilic proteases makes CLSI a very probable contributing factor in joint destruction.