- Stage I:
- represents synovitis:
- synovial membrane becomes hyperemic and edematous with foci of infiltrating small lymphocytes;
- joint effussions w/ high cell count (5,000 to 60,000 per mm3)
- x-rays will as yet show no destructive changes, but soft tissue swelling or osteoporosis may be seen;
- Stage II:
- inflammed synovial tissue now proliferates & begins to grow into joint cavity across articular cartilage, which it gradually destroys;
-narrowing of joint due to loss of articular cartilage;
- Stage III:
- pannus of synovium;
- eroded articular cartilage & exposed sub-chondral bone;
- x-rays will show extensive cartilage loss, erosions around the margins of joint, and deformities may have become apparent;
- Stage IV:
- end stage disease;
- inflammatory process is subsiding;
- fibrous or bony ankylosing of joint will end its functional life;
- subcutaneous nodules associated w/ severe disease