Adult-Onset Still's Disease

This is the classic picture of adult-onset Still's disease - a systemic autoinflammatory disorder driven by the IL-1, IL-18 and IL-6 axis. The classic tetrad is a daily, quotidian spiking fever, an evanescent salmon-pink macular rash that typically appears with the fever spikes and fades between them, arthralgia or arthritis, and a strikingly high ferritin, characteristically with a low glycosylated fraction; supporting features are sore throat, lymphadenopathy, hepatosplenomegaly and a neutrophilic leucocytosis, with negative ANA and rheumatoid factor. I would apply the Yamaguchi criteria, but crucially this is a diagnosis of exclusion, so I would first rule out sepsis, malignancy - especially lymphoma - and other connective-tissue disease. I would watch for macrophage activation syndrome, the feared complication, in which the ferritin soars further with cytopenias, coagulopathy and organ dysfunction - a medical emergency. Management is medical and led by rheumatology: NSAIDs for mild disease, corticosteroids for systemic flares, methotrexate as a steroid-sparing agent, and IL-1 biologics such as anakinra or IL-6 biologics such as tocilizumab for refractory or chronic disease and for MAS. From an orthopaedic standpoint, the relevant feature is the chronic articular form, which can cause a destructive arthritis, classically carpal arthritis progressing to wrist ankylosis, and any joint surgery should be coordinated with the rheumatology team.