sJIA Flashcards
ILAR criteria for sJIA
Arthritis in any number of joints together with fever of at least 2 weeks duration that is documented to be quotiedien for at least three days and is accompanied by one or more of the following:
- Evanescent rash
- Serositis
- Enlarged spleen or liver
- Generalized LAD
Exclusions
- Psoriasis or history of psoriasis in first degree relative
- HLA B27 positive in boy after 6th birthday
- IBD, JAS, Reactive arthritis, ERA, acute anterior uveitis or history of one of these disorders in a first degree relative
- Presence of IgM RF taken three months apart (on at least two occasions
Polymorphisms
MIF, TNFa, IL6, IL-1, IL-1 receptor loci
MIF 173C allele is associated with higher serum and synovial fluid levels of MIF, poor response to steroids, persistently active disease and worse outcome
Classification for MAS
A patient with fever and known or suspected sJIA may be classified as having MAS if the following criteria are presence : Ferritin >684 ng/ml Plus any two of the following - Platelet count <181 x 109/L -AST >48 units/L - Triglycerides > 158 mg/dL - Fibrinogen <360 mg/dL
Pathology of rash
Minimal perivascular infiltration of mononuclear cells around capillaries and venules in the subdermal tissues
A neutrophilic perivasculitis may accompany more flagrant lesions
Prominent expression of endothelial adhesion receptors and s100 proteins MRP8 and MRP14 are seen
Anakinra
IL-1 receptor antagonist
Neutralizes effect of IL-1a and IL1-b
Half life 3-6 hours
Canakinumab
Fully humanized monoclonal antibody to IL-1B
Half life is 25 days
Actemra
Humanized monoclonal antibody to the membrane and the soluble IL6 receptor
Half life is 6 days
Most important early predictors of destructive arthritis
polyarthritis early hip arthritis thrombocytosis persistent fever need for systemic Gas in the first 6 months of disease onset persistently elevated d dimer
Differential dx
Malignancy SLE JDM PAN Kawasaki Serum Sickeness Sarcoidosis Castleman FMF, Mevalonate kinase def, TRAPs, Muckle wells, CINA/Nomid Sepsis, Endocarditis, ARF, Bartonella, Borrelia, Brucellosis, Mycoplasma IBD
Clinical and lab characteristics of MAS
Clinical - Fever, hepatosplenomegaly, LAD, purpura, encephalopathy, bleeding, respiratory distress, renal failure, seizures, AMS, shock
Labs: Cytopenia (esp platelets), dropping ESR, elevated ferritin, d dimer, PT and PTT, elevated LFTs, elevated TG and LDH, CSF may show pleocytosis and elevated protein
Complications of sJIA
Amyloidosis
When are pulse dose steroids appropriate treatment?
Pericarditis, very severe disease, impending MAS
MAS may be linked to mutations in these genes
PRF1, MUNC13-14, LYST, STXBP2
Which infections can trigger MAS
HHV and EBV
Treatment for amyloidosis
- chlorambucil
- TNF inhibitors
- Actemra
