Rheumatism and the Tick—How are they Connected? A 10-Year-Old Girl with Pronounced Knee Swelling

The differential diagnosis for acute knee joint swelling is broad: In addition to acute post-traumatic, inflammatory diseases must be considered. In the spectrum of acute infectious-inflammatory joint inflammations, Lyme arthritis, predominantly of the knee joint and other large joints, is an important diagnosis to consider, especially in Central Europe. The clinical picture and step-by-step laboratory diagnostics define this diagnosis, which generally has a favorable prognosis in childhood.