How would you manage a patient with strongly suspected Lyme arthritis and negative bacterial synovial fluid cultures who was started on empiric antibiotics against typical bacterial pathogens arthritis before arthrocentesis and collection of cultures?

In a patient with a high clinical suspicion for Lyme arthritis who has negative synovial fluid bacterial cultures after receiving empiric antibiotics for presumed septic arthritis, management should be guided by clinical probability rather than the culture results. Antibiotics given before arthrocentesis predictably reduce the yield of synovial fluid cultures, so negative cultures in this context neither rule out bacterial septic arthritis nor meaningfully argue against Lyme disease. What matter...

I think you have to consider the consequences of being wrong, as we often do in ID. In cases of possible Lyme arthritis, not covering Lyme disease or B. burgdoferi won't affect the joint greatly or the duration of inflammation. (1,2) In cases of possible septic arthritis, not covering S. aureus... well, then, you're talking about a TKA.

SMS

P.S. - The story told in the below reference, shows, once again, that Moms are usually right.

Does anyone know or understand why Drs. Steere, Malawista, Benach,...