Lessons from Lyme arthritis.

Lyme arthritis is the late manifestation of a multi-systemic infectious disease designated Lyme borreliosis (LB) which is caused by the spirochete Borrelia burdorferi. Its arthritic manifestations were first recognized in the small New England villages, "Lyme" and "Old Lyme", for which the disorder is named. While this illness was initially regarded as a rather random clustering of several cases of juvenile chronic arthritis, it now serves as the best example of a chronic arthritis with a recognized infectious origin. Even though the agent has clearly been identified, many riddles concerning Lyme arthritis still exist which demonstrate that even the identification of the causative agent does not solve the problems of an arthritis which so far frequently cannot be properly diagnosed and treated. The intensive study of this disorder, however, has taught important lessons which may also be true for other forms of chronic arthritis in which an infectious cause has not been elucidated. Rather than just adding another review on Lyme arthritis to the many good ones that already exist, this paper will focus on these messages.