Rheumatoid Arthritis Diagnosis

See Rheumatoid Arthritis Prediction Rule for Undifferentiated Arthritis
History and Examination are most important
1. Symmetric involvement
2. Morning stiffness and gelling
3. Hand and wrist (esp. MCP joints) involvement
4. Shaking hands is painful (withdraws hand on squeeze)
5. Characteristics of onset
  1. Onset over weeks to months
  2. Prodromal symptoms of Anorexia, weakness, Fatigue
  3. Usually starts in one joint
Lab and x-ray add little help in diagnosis
1. Erythrocyte Sedimentation Rate (ESR) may be normal
2. C-Reactive Protein may be normal
3. Rheumatoid Factor may be normal
4. X-Ray may be normal

Joint Involvement
1. Large joints: Shoulders, elbows, hips, knees and ankles
2. Small joints: MTP, PIP, DIP and wrists
3. Points 0: One large joint involved
4. Points 1: Two to ten large joints involved
5. Points 2: One to three small joints involved (with or without large joint involvement)
6. Points 3: Four to ten small joints involved (with or without large joint involvement)
7. Points 5: More than 10 joints involved (with at least one small joint involved)
Serology (Rheumatoid Factor, Anti-Citrullinated Protein Antibody)
1. Points 0: RF negative and ACPA negative
2. Points 2: Low positive RF or ACPA
3. Points 3: High positive RF or ACPA
Acute Phase Reactants (C-Reactive Protein, Erythrocyte Sedimentation Rate)
1. Points 0: Normal C-RP and ESR
2. Points 1: Abnormal C-RP or ESR
Duration of symptoms
1. Points 0: Less than 6 weeks
2. Points 1: Six weeks or more

Total score (four components above are added)
1. Score of 6 or greater is needed for definitive diagnosis of Rheumatoid Arthritis