<unk>  <unk>  is a severe, potentially life-threatening, complication of several chronic rheumatic diseases of childhood. It occurs most commonly with systemic-onset juvenile idiopathic arthritis (SoJIA), which is also known as Still's disease. In addition,<unk>  has been described in association with systemic lupus erythematosus (SLE), Kawasaki disease, and adult-onset Still's disease. It is thought to be closely related and pathophysiologically very similar to reactive (secondary) hemophagocytic lymphohistiocytosis (HLH). The incidence of<unk>  is unknown as there is a wide spectrum of clinical manifestations, and episodes may remain unrecognized.
Macrophage-activation syndrome
Systemic inflammatory response syndrome
Multiple organ dysfunction syndrome
Immune reconstitution inflammatory syndrome
DRESS syndrome
Herxheimer reaction
Tumor lysis syndrome
COVID-19-associated coagulopathy