Macrophage Activation Syndrome and Acute Kidney Injury in Adult-Onset Still’s Disease Despite IL-6 Inhibition: Managed with Intravenous Anakinra

This report describes a rare case of adult-onset Still’s disease (AOSD) complicated by macrophage activation syndrome (MAS) and acute kidney injury (AKI), despite ongoing interleukin-6 (IL-6) inhibition. The case highlights the diagnostic challenges of MAS in patients receiving IL-6 blockade, particularly in the absence of advanced cytokine or natural killer-cell testing. Timely ferritin monitoring was crucial in confirming MAS. Successful management with corticosteroids and intravenous anakinra prevented the need for dialysis, even in the context of a suspected infection. Only twelve cases of AOSD associated with AKI have been reported in the medical literature as of 2023. Cases of MAS have also been reported in patients receiving biological therapies.