Hemophagocytic Lymphohistiocytosis (HLH)

Definition: Overwhelming clinical syndrome associated with excessive macrophage activation and cytokine storm due to an underlying genetic immune dysfunction. It is rare in presentation, and most frequently affects infants < 3 months of age, however the disease is also observed in adults.

Presentation / Diagnosis:

HLH signs and symptoms can mimic common infections. It presents as an acute or subacute febrile illness associated with multiple organ

involvement.  Diagnosis via genetic testing for HLH-associated mutations OR 5 of the following:

 • Fever ≥38.5°C

 • Splenomegaly

 • Low or absent NK cell activity

 • Ferritin >500 ng/mL

 • Elevated soluble CD25

 • Elevated CXCL9

 • Hypertriglyceridemia

 • Hemophagocytosis in bone marrow, spleen, lymph node, or liver

 • Bicytopenia

Treatment: 

 • Infection should be diagnosed rapidly, and empiric antibiotic therapy should be initiated depending on the suspected organism

 • Supportive measures and treating the insulting agent are the main goal of therapy. If no response HLH-94-based therapy with etoposide and dexamethasone is indicated



By @TheIDtrivia



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