Making sense of the cytokine storm: a conceptual framework for understanding, diagnosing, and treating hemophagocytic syndromes.

Cytokine storm syndromes (CSS) are a group of disorders representing a variety of inflammatory causes. The clinical presentations of all CSS can be strikingly similar, creating diagnostic uncertainty. However, clinicians should avoid the temptation to treat all CSS equally, because their inciting inflammatory insults vary widely. Failure to identify and address this underlying trigger results in delayed, inoptimal, or potentially harmful consequences. This review places the hemophagocytic syndromes hemophagocytic lymphohistiocytosis and macrophage activation syndrome within a conceptual model of CSS and provides a logical framework for diagnosis and treatment of CSS of suspected rheumatic origin.