Reactive Arthritis - Causes

Causes

It is set off by a preceding infection, the most common of which would be a genital infection with Chlamydia trachomatis in the US. Other bacteria known to cause reactive arthritis which are more common worldwide are Ureaplasma urealyticum, Salmonella spp., Shigella spp., Yersinia spp., and Campylobacter spp. A bout of food poisoning or a gastrointestinal infection may also precede the disease (those last four genera of bacteria mentioned are enteric bacteria). There is some circumstantial evidence for other organisms causing the disease, but the details are unclear. Reiter's Syndrome usually manifests about 1–3 weeks after a known infection. The mechanism of interaction between the infecting organism and the host is unknown. Synovial fluid cultures are negative, suggesting that reactive arthritis is caused either by an over-stimulated autoimmune response or by bacterial antigens which have somehow become deposited in the joints.