What is pseudoseptic arthritis?
Pseudoseptic arthritis is seen in the setting of poorly controlled RA in which the patient presents with one or more inflamed joints with very high synovial fluid WBC counts (>100,000 cells/mm 3 ). The cultures are negative, and patients respond to increased corticosteroids rather than antibiotics. However, infection always needs to be ruled out first! This presentation may also be seen in the crystal-induced arthritides, seronegative spondyloarthropathies, and viscosupplementation for osteoarthritis, especially in a patient with calcium pyrophosphate dihydrate deposition disease who gets Synvisc.