What is antibiotic refractory Lyme arthritis and how is it treated?
Up to 10% of patients with Lyme arthritis continue to experience synovitis despite completion of two courses of antibiotics. PCR testing of synovial fluid and/or tissue specimens yields negative results in these patients. It has been hypothesized that these patients carry particular class II major histocompatibility genes (HLA-DR4 and DR2 alleles) which can bind an epitope of B burgdorferi outer surface protein A (OspA) that cross-reacts with a human protein, leading to autoimmune joint inflammation. Additional courses of antibiotic therapy are not recommended given the absence of persistent infection. Instead, these patients should receive symptomatic treatment including nonsteroidal antiinflammatory drugs, intraarticular corticosteroid injections, or disease-modifying antirheumatic drugs including hydroxychloroquine. If synovitis persists in spite of these treatments, arthroscopic synovectomy is advised.