From the Guidelines
Spirochetes are not typically seen in Lyme arthritis. Lyme arthritis is a late manifestation of Lyme disease where the causative organism, Borrelia burgdorferi, has already disseminated throughout the body but is present in very low numbers in the affected joints [ 1 ]. Direct visualization of spirochetes in synovial fluid or tissue samples from patients with Lyme arthritis is extremely rare. Instead, diagnosis relies on clinical presentation, serologic testing showing antibodies against B. burgdorferi, and sometimes PCR testing of synovial fluid which can detect bacterial DNA [ 1 ]. Some key points to consider in the diagnosis of Lyme arthritis include:
- Clinical presentation, typically monoarticular or oligoarticular arthritis affecting large joints, especially the knee
- Serologic testing showing antibodies against B. burgdorferi (both IgM and IgG)
- PCR testing of synovial fluid, which can detect bacterial DNA and is >75% sensitive for Lyme arthritis [ 1 ] The pathophysiology involves an immune-mediated inflammatory response triggered by the initial infection, rather than active bacterial proliferation in the joint [ 1 ]. This explains why some patients continue to have arthritis symptoms even after appropriate antibiotic therapy has eliminated viable organisms, as the inflammation can persist due to residual bacterial antigens or autoimmune mechanisms.
From the Research
Spirochetes in Lyme Arthritis
- Spirochetes are the causative agents of Lyme disease, which can lead to Lyme arthritis in some patients 2, 3, 4.
- The presence of spirochetes in Lyme arthritis is typically confirmed through serologic testing, such as ELISA and Western blot, rather than direct visualization 2, 3, 4.
- Research suggests that while antibiotic therapy can cure most cases of Lyme arthritis, some patients may experience persistent symptoms due to the presence of spirochete antigens or debris, rather than active infection 5, 6.
- A study using intravital microscopy and a mouse model of Lyme borreliosis found that Borrelia burgdorferi antigens can persist near cartilage after antibiotic treatment, even in the absence of infectious spirochetes 6.
Detection of Spirochetes
- Synovial fluid polymerase chain reaction for B burgdorferi DNA can be positive before treatment, but is not a reliable marker of spirochetal eradication after therapy 3.
- Spirochete antigens can be detected in tissue homogenates from antibiotic-treated mice, and can stimulate TNF-α production from macrophages in vitro 6.
- The presence of spirochetes in Lyme arthritis can be inferred through clinical manifestations, such as joint swelling and pain, and serologic testing, rather than direct visualization 2, 3, 4.