Adult-Onset Still's Disease in a Patient with Macrophage Activation Syndrome and Pre-Disseminated Intravascular Coagulation: A Case Report and Literature Review.

Background: Adult-onset Still's disease (AOSD) is a rare autoinflammatory condition characterized by high spiking fevers, arthralgia, typical rash, and systemic inflammation. Life-threatening complications, such as macrophage activation syndrome (MAS) and disseminated intravascular coagulation (DIC), may arise. Prompt recognition and intensive management are crucial for patient survival. This report presents a case of AOSD complicated by MAS and pre-DIC, accompanied by a review of the relevant literature. Case Presentation: A 22-year-old male presented with recurrent high-grade fever, generalized red rash, lymphadenopathy, splenomegaly, and knee arthralgia. He met the Yamaguchi criteria for AOSD and the Ravelli criteria for MAS, and was diagnosed with pre-DIC using the Chinese Diagnostic Scoring System for DIC (CDSS). Following diagnosis, the patient received a comprehensive medical regimen that included glucocorticoids, the JAK inhibitor tofacitinib, infusion of fresh frozen plasma, and supportive care, resulting in clinical improvement. At the 8-month follow-up evaluation, the patient's condition remained stable without any signs of progression. Conclusion: This case underscores the critical importance of early identification of MAS and pre-DIC in AOSD, and demonstrates that aggressive immunosuppressive and supportive therapy, implemented within a multidisciplinary framework, is essential to prevent progression to overt DIC and multi-organ failure.