Definition
Rheumatoid arthritis (RA) is a systemic autoimmune disease. It is a chronic, progressive disease that alternates between periods of remission and flare-ups. Its etiology remains unknown. It is primarily characterized by inflammation of the inner lining of the joints (symmetrical synovitis). In the long term, it leads to joint erosion, resulting in chronic pain and loss of function. It presents with multisystemic extra-articular manifestations (myocarditis, pleurisy, polyneuropathy, keratoconjunctivitis).
Clinical Presentation
| Symptoms |
|---|
| Systemic or Joint-Related |
| Flu-like symptoms, including a low-grade fever. |
| Fatigue |
| General malaise |
| Loss of appetite, weight loss, anemia |
| Depression |
| Thrombocytosis |
| Diffuse musculoskeletal pain |
| Symmetrical polyarthritis** |
| Morning stiffness or stiffness after prolonged immobility*** |
| Pain with movement |
| Joint tenderness |
| Localized redness |
| Subcutaneous nodules, typically on the elbows**** |
| Involvement of the salivary and lacrimal glands (Sjögren’s syndrome) |
| ACR criteria* |
|---|
| Morning stiffness lasting more than 1 hour |
| Arthritis in 3 or more joint regions |
| Arthritis in the joints of the hand |
| Symmetrical arthritis |
| Rheumatoid nodules |
| Serum RF |
| Radiographic changes |
* American College of Rheumatology
** Joint involvement usually begins in the small joints of the fingers and wrists.
*** Typically, the longer the duration of morning stiffness, the more active the disease is.
**** Indicators of increased disease activity
Laboratory tests
| General |
|---|
| Complete blood count |
| Erythrocyte Sedimentation Rate |
| C-reactive protein |
| Urea / Creatinine |
| Electrolyte Panel |
| Uric Acid |
| Liver Function Tests |
| Viral Serology (HBV, HCV) |
| Synovial Fluid Analysis |
| Specific |
|---|
| Anti-CCP2* Antibodies (IgG) |
| RA Test |
| Rheumatoid Factor (RF) (IgM) |
| Antinuclear Antibodies (ANA) |
*Cyclic Citrullinated Peptide (CCP2) - 2nd generation
Key Information
- Early diagnosis is of the utmost importance
- Structural damage occurs in the early years
- Timely treatment slows the progression of the disease
- Early treatment allows patients to continue leading active and productive lives.
Proposed algorithm for laboratory diagnosis
Clinical and laboratory characterization
| Anti-CCP2 antibodies |
|---|
| Sensitivity: 87.8% |
| Specificity: 97% |
| Positive Predictive Value: 98% |
| Anti-FR Antibodies |
|---|
| Sensitivity: 78% |
| Specificity: 62% |
Anti-CCP2 antibodies occur exclusively in patients with rheumatoid arthritis and are found in approximately 80% of patients with RA. They are not associated with any other condition.
Anti-CCP2 antibodies may appear years before the onset of the first symptoms
Anti-CCP2 antibodies have prognostic value regarding joint destruction
Anti-CCP2 antibodies are often found in patients with rheumatoid arthritis who are rheumatoid factor-negative.
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