Hemophagocytic syndromes

This code represents a group of rare, life-threatening immune disorders characterized by uncontrolled activation and proliferation of histiocytes and T-lymphocytes, leading to excessive inflammation and tissue damage. It involves the phagocytosis of hematopoietic cells by macrophages, often resulting in cytopenias and organ dysfunction.

Use this code for patients diagnosed with hemophagocytic lymphohistiocytosis (HLH), either primary (genetic) or secondary (acquired). Documentation should clearly indicate findings such as fever, splenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenemia, elevated ferritin, and evidence of hemophagocytosis in bone marrow or other tissues.

• Distinguish between primary (familial) and secondary (infection-associated, malignancy-associated, autoimmune-associated) forms when documented, as this may impact further specificity in newer code sets.
• Always code any underlying cause or associated condition (e.g., infection, malignancy, autoimmune disease) that triggers secondary HLH.
• Consider sequencing the underlying cause first if it is the primary reason for the encounter, followed by this code for the manifestation.