Reactive and enteropathic arthritis

Abstract

The role of infection as a triggering factor in the pathogenesis of the various forms of spondyloarthritis (SpA) is implicated with varying degrees of certainty among the SpA subcategories. The very definition of reactive arthritis (ReA)-A sterile synovitis following an extra-articular infection-clearly implicates infection in its defining features, and ReA occupies the conceptual ground somewhere between septic arthritis and the classic autoimmune rheumatic diseases, such as rheumatoid arthritis (RA). An etiologic classification has fueled the search for definitive links between particular pathogens and ReA. Many of these studies are based on guilt by association, in that the demonstration of a particular immune response profile by serology or cellular responses leads to identification of the causative pathogen even when there is no direct demonstration of the organism or its antigens in synovial tissues or fluid. The predictive power of a diagnostic microbiology test, however, critically depends on the prevalence of positives in the healthy population at large (1), and this is an important consideration in the case for causality in ReA. © 2008 Springer-Verlag New York.