Alzheimer's disease
Overall there is still no evidence that short term treatment of enteric infections with antibiotics prevents reactive arthritis, but treatment ofchlamydial infections does probably reduce the risks of postvenereal arthritis.
Abstract
synovial tissue from patients with reactive arthritis, indicating an inflammatory process that might be driven by continuous antigen stimulation.35 Chlamydial inclusion bodies and chlamydial DNA have also been found in synovial specimens.6 In laboratory experiments synovial mononuclear cells from patients proliferate when challenged with bacteria associated with reactive arthritis, the maximum response being to the triggering organism. This might act as the initiator of the synovial inflammation.7 Whether viable bacteria are present in the joint as well is of interest when antimicrobial treatment of reactive arthritis is considered. So far, cultures from synovial fluid have yielded negative results-with a few exceptions, all chlamydia.' The relation between HLA-B27 and bacteria in the pathogenesis of reactive arthritis remains unclear. The molecular mimicry theory implies immunological cross reactivity between HLA-B27 and microbial antigens. Alternatively, HLA-B27 might act as a receptor for bacterial proteins, resulting in a "foreign" complex subjected to immune attack.' The treatment of reactive arthritis is with non-steroidal anti-inflammatory drugs, intra-articular injections of steroid, and physical treatments. The place of antibiotics is still controversial.8 In retrospective studies no difference in preventing the arthritis was found between patients who were given antibiotics and those who were not, suggesting that the events causing reactive arthritis take place early during the infection. On the other hand, relapses of postvenereal arthritis in patients with Reiter's syndrome were reduced when the urethritis was treated with antibiotics.9 Short term treatment with antibiotics had no beneficial effect on postenteric reactive arthritis in a prospective study,'0 whereas in arthritis triggered by yersinia treatment for four to six weeks resulted in clinical improvement accompanied by disappearance of yersinia antigen in intestinal biopsy specimens and of serum IgA antibodies to yersinia.4 In a placebo controlled study three months' treatment with lymecycline shortened the duration of arthritis. The antiinflammatory effect of lymecycline may have contributed to the favourable outcome, but this was restricted to patients with postvenereal disease." In another study a three month course of ciprofloxacin in postenteric reactive arthritis had no convincing effect.12 Overall there is still no evidence that short term treatment of enteric infections with antibiotics prevents reactive arthritis, but treatment ofchlamydial infections does probably reduce the risks ofpostvenereal arthritis. Short term treatment with antibiotics does not seem to have any beneficial effect in established reactive arthritis, whereas some tendency to improvement has been seen with treatment lasting monthsat least after chlamydia infection. Prospective studies with well defined patients and controls are still needed before any firm recommendations for antibiotic treatment can be given. Such studies should take into consideration the triggering microbe, the duration of the arthritis before treatment, and the presence of HLA-B27. Appropriate antibiotics, doses, and the optimal duration of treatment have to be established. Ideally, the synovial fluid should be examined for microbial antigens and the serum antibody concentrations should be monitored during treatment. Such studies will probably have to be multi centre.