Migrating Swollen Joint and Lyme Disease: A Case Report

This article discusses a case involving a pediatric patient who presented to a large urban children's hospital in the Northeastern United States with complaints of migratory monoarticular joint swelling. The patient had presented with a swollen and painful left knee but with no other associated symptoms. He was nontoxic appearing, afebrile, and had normal vital signs. On examination, he was noted to have a tender and swollen left knee that was not erythematous, bruised, or warm to the touch. There was a history of fevers over the summer after returning home from a camping trip in a park located in the northeastern United States. A plain film knee x-ray showed signs of joint effusion but no osseous abnormalities. A bedside ultrasonography of the knee showed a pocket of fluid in the joint space. With parental consent, the left knee joint was aspirated under direct ultrasound guidance, with collection of dark yellow synovial fluid. This was sent for analysis that included cultures, Gram stain, crystal analysis, and Lyme antigens. The patient was admitted, and his symptoms improved during his hospitalization. The results were positive for Lyme and he was discharged home on a 3-week course of Amoxicillin with complete resolution of his symptoms.