Joint aspirate in rheumatoid arthritis typically shows which characteristic?

• A. Non-inflammatory clear fluid
• B. Purulent septic fluid
• C. Inflammatory synovial fluid with elevated WBC and decreased viscosity
• D. Hemorrhagic joint aspirate

Answer: (C)

Inflammatory arthritis such as rheumatoid arthritis produces inflammatory synovial fluid. This means the aspirate is often turbid or cloudy with an elevated white blood cell count, typically neutrophil-predominant, reflecting inflammatory cell influx into the joint. At the same time, the fluid’s protein content is high and its viscosity is decreased, so it feels thinner than normal. This combination—high WBCs with decreased viscosity—is characteristic of RA-related synovial fluid.

In contrast, non-inflammatory effusions are clear with low WBCs, septic (purulent) fluid is usually grossly purulent and often has positive cultures, and hemorrhagic effusions are blood-tinged from bleeding into the joint.