Juvenile Idiopathic Arthritis
JIA
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Oligoarthritis (1-4 joints within the first 6 months) can be ANA pos
Clinical Manifestations
preliminary MAS criteria (work in progress) any 2 of:
Rx Pulsed methylprednisolone, cyclosporine, anakira
Ophthalmology screening
Rx
Immunomodulators
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Oligoarthritis (1-4 joints within the first 6 months) can be ANA pos
- Persistent oligoarthritis (remains <5 joints)
- No FHx psoriasis, FH spondyloarthropathy, RF positivity, no HLA B27 in male over 6 years, not meeting Dx SJIA.
- knees most common > ankles, wrists and elbows
- Ophthalmologist screen q3months for chronic uveitis (photophobia red eyes visual changes) untreated leads to band keratopathy, cataract and glaucoma > blindness
- physiotherapy and exercise
- NSAID
- Intra-articular corticosteroid injections (IACI) to avoid asymmetrical growth, subluxation or ankylosis can be avoided.
- Extended oligoarthritis (progresses to after the first 6 months)
- Methotrexate
- large and small limb joints, cervical spine and MTJ
- Ophthalmology screening for uveitis
- NSAIDs may be used to treat symptoms
- Methotrexate for maintenance (PO (variable absorption), IM (better), SC (similar to IM but better compliance as less pain)
- Symmetrical polyarthritis affecting the upper (e.g. metacarpophalangeal joints most common) and lower limbs.
- Subcutaneous nodules and early erosive changes radiologically
- Rx
- etanercept: tumour necrosis factor (alpha) inhibitor
- abatacept: humanised selective T-cell co-stimulatory modulator
- monoclonal antibodies adalimumab and infliximab.
- Quotient fever >38.5C for 2w (same time daily or BD)
- Salmon pink rash (evanescent, non-fixed ie coming and going with fever)
- Polyarticular arthritis >6w (often delayed months after systemic features
- If no arthritis yet > 2 of lymphadenopathy; hepatomegaly or splenomegaly; serositis
Clinical Manifestations
- Fever – 98 percent
- Arthritis – 88 percent (8 percent with monoarthritis, 45 percent with oligoarthritis, and 47 percent with polyarthritis)
- Rash – 81 percent (macular salmon pink, with fevers)
- Lymphadenopathy – 31 percent
- Hepatomegaly, splenomegaly, and lymphadenopathy (DDx malignancy > LN biopsy)
- Serositis inc pericarditis +/- effusion, rarely tamponade, pleural effusion
- Myocarditis
- WC 20-30 (can get to 80) with predominance of granulocytes
- Plt 200-1000 (<200 need to think about DDx)
- Anaemia
- Elevated CRP / ESR (other Dx if normal in acute phase)
- NB sudden drop in ESR and plt to normal heralds Macrophage Activation Syndrome, ferritin spike confirms
- Ferritin 1,000-50,000
- ANA and RF should be negative
preliminary MAS criteria (work in progress) any 2 of:
- Platelet count ≤262,000 platelets/microL
- Aspartate aminotransferase (AST) >59 units/L
- White blood cell count ≤4000 cells/microL
- Central nervous system dysfunction
- Bleeding/purpura
- Hepatomegaly
- (Ferritin >500 helps differentiate sJIA with MAS from other systemic disorders but not from each other)
Rx Pulsed methylprednisolone, cyclosporine, anakira
Ophthalmology screening
- 10. MAS is a rare complication of systemic arthritis, involving increased activation of histiophagocytosis. Triggers include preceding viral illness (e.g. EBV) and additional medications (particularly NSAIDs, sulfasalazine and etanercept). Clinical findings include lymphadenopathy, hepatosplenomegaly, purpura, mucosal bleeding and multiple organ failure. Investigations may show pancytopenia, prolonged prothrombin time and partial thromboplastin time, elevated fibrin degradation products, , hypertriglyceridaemia and low ESR.
Rx
- Systemic JIA
- Interleukin-1 blockers anakinra and canakinumab
- interleukin-6 blocker tocilizumab.
- Polyarticular JIA
- etanercept: tumour necrosis factor (alpha) inhibitor
- abatacept: humanised selective T-cell co-stimulatory modulator
- monoclonal antibodies adalimumab and infliximab.
- Enthesitis-related arthritis
- TNF inhibitors etanercept, adalimumab and infliximab.
- oligoarticular JIA
- intra-articular corticosteroid injections (IACI)
Immunomodulators
- Screen for TB
- Councel re risks of immunosuppression / malignancy
- Monitor for pancytopenia