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Evidence for intravascular coagulation in systemic onset, but not polyarticular, juvenile rheumatoid arthritis
Insights
Systemic onset juvenile rheumatoid arthritis (S-JRA) often involves intravascular coagulation, unlike rheumatoid factor-negative polyarticular JRA (P-JRA). This coagulopathy and endothelial cell activation in S-JRA may lead to severe complications.
Area of Science:
- Pediatric Rheumatology
- Hematology
- Coagulation Disorders
Background:
- Systemic onset juvenile rheumatoid arthritis (S-JRA) can present with severe thrombotic complications.
- Purpura fulminans and disseminated intravascular coagulation have been observed in S-JRA patients.
Purpose of the Study:
- To prospectively investigate coagulation parameters in children with S-JRA and rheumatoid factor-negative polyarticular JRA (P-JRA).
- To assess the prevalence of intravascular coagulation and endothelial cell activation in different JRA subtypes.
Main Methods:
- Studied 10 children with S-JRA, 10 with P-JRA, and 10 controls.
- Performed routine coagulation tests, plasma fibrinopeptide A, factor VIII-related antigen, and platelet factor 4 assays.
Main Results:
- Intravascular coagulation activation was common in S-JRA but not P-JRA.
- Elevated factor VIII-related antigen in S-JRA suggests endothelial perturbation and vascular involvement.
- Platelet factor 4 levels were normal, indicating no intravascular platelet consumption in either JRA type.
Conclusions:
- Intravascular coagulation is a frequent finding in S-JRA, potentially causing significant morbidity.
- Endothelial cell activation and vascular involvement are characteristic of S-JRA.
- P-JRA does not exhibit the same pro-coagulant state or vascular markers as S-JRA.
Abstract:
After observing a child with systemic onset juvenile rheumatoid arthritis (S-JRA) who developed purpura fulminans in association with disseminated intravascular coagulation, with subsequent gangrene and autoamputation, we undertook a prospective study of coagulation parameters in children with JRA. Ten consecutive children with S-JRA, 10 children with rheumatoid factor-negative, polyarticular juvenile rheumatoid arthritis (P-JRA), and 10 age- and sex-matched controls were studied. Routine coagulation screening tests were performed, as were tests for plasma fibrinopeptide A (a sensitive measure of intravascular thrombin generation), factor VIII-related antigen (an endothelial cell protein), and platelet factor 4 (a platelet-secreted protein). Our studies suggest that activation of intravascular coagulation is common in systemic onset JRA, but not in rheumatoid factor-negative, polyarticular disease. The coagulopathy may cause severe morbidity. In addition, marked elevations of plasma factor VIII-related antigen suggest perturbation of endothelial cells and vascular involvement in S-JRA, but not in P-JRA. Normal ranges of platelet factor 4 indicate that intravascular platelet consumption does not occur in either type of JRA, despite the thrombocytosis common in both.