What are Rheumatoid Factors? Autoantibodies reactive with the Fc portion of IgG Its presence is NOT specific for RA Frequency increases with age – 10-20% of individuals >65 y/o test positive despite not having RA
Other conditions associated with the presence of rheumatoid factors: Systemic Lupus Erythematosus Sjögren’s Syndrome Chronic liver disease Sarcoidosis Interstitial pulmonary fibrosis Infectious mononucleosis Hepatitis B Tuberculosis Leprosy Syphillis Subacute bacterial endocarditis Visceral leishmaniasis Schistosomiasis Malaria Healthy individuals > 65 years old Post-vaccination Post-transfusion Relatives of patients with RA
Rheumatoid factor is used only to evaluate. It is NOT used as a screening procedure Predictive value of the presence of rheumatoid factor in determining a diagnosis of RA is poor < 1/3 of patients with (+) rheumatoid factor will be found to have RA Evaluate severity and progression – ↑ titer = ↑ severity
Anti-Cyclic Citrullinated Peptide (Anti-CCP) Most commonly found in patients with: – (+) rheumatoid factor – Aggressive disease bone errosions – RA-associated HLA-ß1 allele – Smokers Early detection of RA Sensitivity: anti-CCP = rheumatoid factor Specificity: anti-CCP > rheumatoid factor Confirm diagnosis, establish prognosis Disadvantage vs. rheumatoid factor: not useful in predicting the future development of RA – Can’t evaluate severity and progression
Hematologic Findings Complete Blood Count w/ Platelet Count and Differentials – Normochromic, normocytic anemia ineffective erythropoiesis – Thrombocytosis – Usually normal WBC count but… May have mild leukocytosis Felty’s syndrome – leukopenia Severe systemic disease – eosinophilia ↑iron stores in bone marrow ↑ erythrocyte sedimentation rate
Other serologic findings Acute phase reactants – Ceruloplasmin – C-reactive protein Correlate with disease activity and likelihood of progressive joint damage
Confirms presence of inflammatory arthritis Non-specific Characteristics of synovial fluid – Physical Turbid Reduced viscosity – Clinical chemistry Increased protein content Normal / slightly decreased glucose concentration – Cell count WBC varies from 5 to 50,000/uL; PMNs predominate – >2000/uL with > 75% PMNs = inflammatory arthritis – Non-diagnostic of RA – C3 & C4 markedly diminished Synovial fluid analysis
Radiographic Evaluation None of the radiographic findings is diagnostic of RA Early in the disease – usually NOT helpful; will only reveal the “obvious”, not help significantly in management As the disease progress – abnormal findings more pronounced
Characteristic patterns of abnormalities seen in radiographs Symmetric involvement Juxtaarticular osteopenia Loss of articular cartilage – Radiography would determine the extent of cartilage destruction Bone erosion X-rays of the hands in Rheumatoid arthritis. Demonstrates periarticular porosis, joint space narrowing of the proximal interphalyngeal joints, and erosions. Note erosion of the ulnar styloid, and narrowing of the wrists.
Other imaging procedures 99m Tc bisphosphonate bone scanning MRI Technetium-99 bone scan in a patient complaining of stiffness and painful joints but a NORMAL examination, showing uptake of technetium in sub clinical inflammation of joints. Note symmetrical, polyarticular uptake pattern (hands, feet and knees demonstrated)- typical of Rheumatoid arthritis.
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