24th February 2025

Management of JIA

The recurring theme, regardless of JIA-subtype is early administration of NSAIDs. For oligo-JIA (less than or equal to four joints), intra-articular corticosteroid is given as a bridge for disease-modifying therapy to take effect, which is typically methotrexate. For poly-JIA (more than or equal to five joints), oral corticosteroid is substituted. If methotrexate is poorly tolerated or disease is refractory, then either the DMARD is substituted like in RA, or usually biologic therapy is initiated (similar agents as used in RA). Systemic-JIA (around 5% of cases, previously known as Still’s disease) usually has grossly elevated WCC, CRP and ESR counts on laboratory investigations and is managed similarly to other subtypes of JIA, but with a lower threshold for biologics.

A recognised complication is secondary haemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS), where haemopoietic stem cells in the bone marrow are destroyed by macrophages as part of the ‘cytokine storm’ in response to an infective trigger. This has non-specific features, but the child is invariably unwell with severe systemic upset and often multi-organ failure. It is diagnosed in the setting of cytopenias, falling inflammatory markers, platelets and fibrinogen and elevated ferritin and triglycerides. As well as providing organ support, treatment involves aggressive broad-spectrum antimicrobial therapy to cover for sepsis and specifically pulsed methylprednisolone, IVIG and then biologics (in that order of escalation). The all-cause mortality in secondary HLH is 8-22%. 

Overall, multidisciplinary team involvement is vital for a good outcome in JIA, and indeed, with modern treatments, outcomes are improving. Reassuringly, the incidence of joint replacement in later life is falling as long-term remission of JIA is now more possible. However, vision loss due to uveitis occurs in approximately 25% of cases with minimal symptoms to suggest deteriorating vision, reiterating the importance of screening programmes. The same concern needs to be had for patients with JIA as with all immunocompromised patients, particularly in regards to opportunistic infections. Vaccinations, including live ones, are still recommended even if immunosuppressed, as their benefits far outweigh the risks.