Long-term management for patients with systemic JIA
The management approach for systemic juvenile idiopathic arthritis (JIA) is described here, including drug choice for long-term management.
Methotrexate, in combination with folic acid, is used initially in children or adolescents who have:
- severe features of systemic JIA
- active polyarthritis despite treatment with a corticosteroid
- arthritis that recurs as the corticosteroid is tapered.
Methotrexate is used for both systemic and arthritic features, despite being poorly effective for systemic features, because it is a prerequisite for accessing biological disease-modifying antirheumatic drugs (bDMARDs) via the Pharmaceutical Benefits Scheme (PBS). Oral bioavailability of methotrexate plateaus above 15 mg; subcutaneous administration may be considered if doses higher than 15 mg are ineffective and may also have the benefit of reducing methotrexate-induced nausea. The usual paediatric dosage is:
1methotrexate 10 to 20 mg/m2 up to 25 mg orally, on one specified day once weekly1 methotrexate methotrexate methotrexate
OR
1methotrexate 10 to 20 mg/m2 up to 25 mg subcutaneously, on one specified day once weekly methotrexate methotrexate methotrexate
PLUS with either of the above
folic acid 5 mg orally, weekly (not on the same day as methotrexate)2. folic acid folic acid folic acid
Ciclosporin has historically been used for systemic JIA and may have a role in some patients with severe macrophage activation syndrome; however, it is seldom used because of the increased availability of bDMARDs.
For patients dependent on corticosteroid therapy for control of systemic features, or those with ongoing active polyarthritis despite the use of methotrexate, bDMARDs may be considered. At the time of writing tocilizumab is the only bDMARD available on the PBS for systemic JIA3. The usual dosage isYokota, 2012:
tocilizumab (child 2 years or older) 162 mg subcutaneously tocilizumab tocilizumab tocilizumab
less than 30 kg: every 2 weeks
30 kg and over: every week
OR
tocilizumab (child 2 years or older and less than 30 kg: 12 mg/kg; child 30 kg or more: 8 mg/kg) intravenously, every 2 weeks. tocilizumab tocilizumab tocilizumab
Alternative bDMARDs sometimes used for systemic JIA are anakinra and canakinumab.
The specialist will determine the appropriate approach to monitoring, screening for infection, and vaccination based on the adverse effect profile of the drug and patient factors (eg disease activity, comorbidities). See also Principles of immunomodulatory drug use.
A significant majority of patients will have a polyarthritic presentation once systemic features settle. See Management for rheumatoid factor negative polyarticular JIA for further pharmacological and nonpharmacological treatment advice.