Lyme arthritis of the pediatric lower extremity in the setting of polyarticular disease

BACKGROUND: Lyme arthritis can be readily treated with use of oral antibiotics without any need for surgery. In Lyme-endemic areas, differentiating between Lyme arthritis and septic arthritis can be difficult. Laboratory testing for Lyme disease often results in a delay in diagnosis because many labs batch-test Lyme specimens only two times per week due to lack of equipment or increased expense. Delayed diagnosis can lead to unneeded surgery in cases in which the surgeon indicates the patient for a joint irrigation and debridement (I & D) for possible septic arthritis while waiting for Lyme serology results. The purpose of this study was to develop an algorithm for the treatment of patients with possible Lyme arthritis, with particular attention to poly-articular involvement. METHODS: Thirty-nine patients with poly-articular Lyme arthritis, including ankle involvement, were reviewed retrospectively. Patients were included if the ankle was involved, if they were less than 18 years of age, and had available laboratory information and a serologic diagnosis of Lyme disease. RESULTS: Only two patients had isolated ankle involvement; of those with poly-articular involvement, 34 patients had ankle/knee involvement. Nine patients presented with pain in the ankle with passive range of motion (PROM) (22 %); two (4.8 %) had refusal to bear weight, and 10 (24 %) had an antalgic gait. All patients had a positive Western blot. Ten patients had a peripheral white blood cell (WBC) count >12,500/mm(3) , and 16 patients had an erythrocyte sedimentation rate (ESR) >40 mm/h. CONCLUSION: Without immediate availability of Lyme serology, the decision to perform surgical drainage of a swollen joint in the setting of possible Lyme arthritis versus septic bacterial arthritis remains a clinical dilemma. Our data suggests that patients presenting with one or fewer Kocher criteria symptoms, poly-articular disease, and minimal pain with PROM have Lyme, rather than septic, arthritis. These patients can be treated with joint aspiration for cultures, appropriate antibiotics for Lyme disease, and careful serial exams while waiting for results of Lyme serology rather than immediate surgical I & D.