The Chameleon of rheumatology: A case of adult-onset Still’s disease

Adult-onset Still's disease (AOSD) is a rare autoimmune disorder with a challenging diagnosis due to its overlapping symptoms with other inflammatory and infectious conditions. This case study describes a 54-year-old man with type 2 diabetes mellitus who presented with persistent fever, weight loss, and multiple organ involvement. Initial investigations, including imaging and laboratory tests, suggested a granulomatous disease, but a definitive diagnosis remained elusive despite extensive workup. The patient's clinical course, marked by fluctuating symptoms and poor response to conventional treatments, eventually pointed towards an underlying autoimmune disorder. A provisional diagnosis of connective tissue disease with a differential diagnosis of AOSD was made, and corticosteroid therapy was initiated. Complications arose with the development of hemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS), a severe, life-threatening condition associated with AOSD. The patient exhibited high ferritin levels, pancytopenia, and multi-organ dysfunction, indicating HLH. Despite aggressive management, including broad-spectrum antibiotics, antifungal therapy, and high-dose corticosteroids, the patient's condition deteriorated, leading to respiratory distress and arrhythmia. He was transferred to the intensive care unit but unfortunately expired. This case highlights the diagnostic challenges of AOSD and its potential to progress to severe complications like HLH. It underscores the need for a multidisciplinary approach in managing such complex cases and the importance of early recognition and aggressive treatment to improve outcomes. The limitations of conventional therapies and the need for targeted treatments and advanced diagnostic tools are also emphasized for better management of AOSD and associated complications.