On the difficulties of establishing a consensus on the definition of and diagnostic investigations for reactive arthritis. Results and discussion of a questionnaire prepared for the 4th International Workshop on Reactive Arthritis, Berlin, Germany, July 3-6, 1999

Objective. There is no agreement on how to classify and diagnose reactive a rthritis (ReA) and it is also unclear what kind of specific clinical and la boratory investigations are appropriate. We define relevant points of agree ment and identify points of disagreement among an international group of ex perts in the field. Methods. Prior to the 4th International Workshop on Reactive Arthritis, Ber lin, July 1999, we sent questionnaires to 42 experts identified by personal knowledge and recent publications. Results. The response rate was 81% (n = 34). There was agreement on the nom enclature and recommendation to use the term "reactive arthritis" only if t he clinical picture and the microbes involved are HLA-B27 and spondyloarthr opathy (SpA) associated, whereas the term "infection related arthritis" is used for ail other arthritides related to or associated with infections. A differentiation between acute and chronic ReA with a cutoff of 6 months is recommended. The history of a preceding symptomatic infection is thought to be most relevant for a diagnosis of ReA. The minimal interval between prec eding symptoms and arthritis is proposed to be 1-7 days, maximally 4 weeks. The joint pattern in ReA is asymmetrical, with predominance of the lower l imbs. SpA related symptoms may contribute to the diagnosis. A search for ch lamydia in urine/urethra/cervix is recommended, while in the case of diarrh ea enterobacteria should be searched for in stool and antibodies against th em in serum. There were also areas of disagreement, such as: Is arthritis e ssential for the diagnosis of ReA?, Is it oligoarthritis or any arthritis?, What are the role and value of polymerase chain reaction investigation?, T he role and value of serology?, Is the diagnostic sensitivity of microbiolo gical tests for ReA increased by HLA-B27 determination? Conclusion. The points of agreement will support better communication in th is area, and clarification of the disagreements will lead to further studie s and discussion.