Joint pain and swelling: could it be lyme arthritis?

This report presents two probable cases of Lyme arthritis triggered by athletic activity or trauma. One patient had ankle swelling after he began a jogging program, and a second had knee swelling that followed a twisting injury. The report describes the three stages of the illness and presents diagnostic lab tests and the therapies used. Polymerase chain reaction (PCR) testing of the synovial fluid can be useful in diagnosing active Lyme arthritis, but it may yield a false-negative result when there has been recent remission of the arthritis.