Rescue Therapy With Continuous Intravenous Anakinra Infusion and Plasma Exchange in Refractory Cytokine Storm of Systemic JIA: A Case Report.

Introduction: Macrophage activation syndrome (MAS) is one of the most common fatal complications of inflammatory diseases in children. In recent studies, Interleukin 1 inhibitors have been shown to be effective in suppressing the cytokine storm in MAS. There is limited literature describing the role of plasmapheresis in the cytokine storm syndromes as in MAS. Case Description: A six-year-old boy presented with a 1-month history of daily fever, arthritis, cervical lymphadenopathy, skin rash, and elevated inflammatory markers. After multidisciplinary evaluation, he was diagnosed with systemic onset Juvenile Idiopathic Arthritis (sJIA) and started on IV methylprednisolone and SC anakinra. He later developed status epilepticus, required intubation, and progressed to multiorgan failure, needing inotropes and dialysis. Following a brief afebrile period, he worsened again, and labs confirmed MAS relapse with ferritin levels peaking at 26,000. Escalated treatment included switching to IV continuous anakinra, adding ciclosporin, and starting plasmapheresis. After three sessions of plasma exchange, he significantly improved, was extubated, and weaned off inotropes. However, attempts to switch anakinra back to SC failed twice, with recurrence of fever, rash, and elevated ferritin. He remained in PICU on IV continuous anakinra for over 3 weeks. When ferritin dropped to 900, an IV bolus regimen was trialed for a week, followed by a successful switch to SC anakinra. The child was discharged home asymptomatic with normalized labs. Conclusion: Anakinra has been used off-label in critically ill patients with MAS, thrombocytopenia, subcutaneous edema, and neurological dysfunction. Tapering from intravenous Anakinra to subcutaneous was challenging. This case taught us that tapering must begin at the right time to avoid hiccups or unfavorable outcomes. As reported in a few studies, plasmapheresis combined with immunosuppressants can reduce MAS-associated mortality by rapidly removing cytokines from the body.