REACTIVE ARTHROPATHIES.

"Reactive arthritis" refers to the occurrence of an acute, non-suppurative, sterile inflammatory arthropathy arising after an infectious process but at a site remote from the primary infection. Reiter's syndrome is one of the most common examples of reactive arthritis. The microbial pathogens commonly associated with reactive arthritis areShigella, Salmonella, Yersinia, Campylobacter,andChlamydia.The reactive nature of these arthritides has been debated, inasmuch asChlamydia, Yersinia,andSalmonellamicrobial antigens have been identified at sites of tissue inflammation, thus suggesting that an ongoing immune response to disseminated material, rather than a reactive condition, may be the pathogenic mechanism. Many reactive arthritides occur after a known infection and have therefore been termed "post-infectious." Although the pathologic processes appear to be similar, this distinction may be important with regard to potential responsiveness to antibiotic therapy.

Reactive arthritis begins as an asymmetrical oligoarthritis, often preceded by an identifiable infectious event by 1 to 4 weeks. The temporal sequence suggests that these reactive disorders are triggered by an antecedent infectious process. Many patients without an identifiable infectious trigger have a similar constellation of signs and symptoms. The findings of sterile inflammatory synovial effusions, lymphocytes at sites of tissue inflammation, responsiveness to anti-inflammatory and immunosuppressive regimens, and the association with HLA-B27 suggest a common immunopathogenesis. Extra-articular manifestations may be a prominent feature of the reactive arthropathies. Although frequently self-limiting, these disorders have the potential for chronicity and serious articular damage to the peripheral or axial joints.