Diagnostic criteria for rheumatoid arthritis

*1. What are the 7 diagnostic criteria for RA? How many must be satisfied for diagnosis?
*2. What joints of the hand are usually affected by RA?
3. What lab tests are ordered to assess for RA?
*4. What does the synovial fluid show in RA?
*5. What percentage of RA patients are RF+?
6. What are diseases may show +RF?

Answers:
1. Must satisfy 4/7: morning stiffness >1hr, arthritis of >3 jts, arthritis of at least one joint in hand, symmetric, rheumatoid nodules, RF+, radiographic changes (erosions, bony decalcification, symm jt space narrowing).
2. PIP, MCP, MTP.
3. RF, ESR, CRP, CBC, synovial fluid.
4. Low viscosity, 1000-75,000 WBC (>70% PMN).
5. 85%, often assoc with severe active disease.
6. SLE, scleroderma, Sjogren's, viral, parasitic, bacterial, neoplasms, hyperglobulinemic.