hemophagocytic lymphohistiocytosis
Meaning of hemophagocytic lymphohistiocytosis: Hemophagocytic lymphohistiocytosis is a rare, life-threatening syndrome of overwhelming immune activation that damages organs and destroys blood cells.
Definition of hemophagocytic lymphohistiocytosis
Hemophagocytic lymphohistiocytosis is a rare and serious condition in which immune cells, particularly certain white blood cells called histiocytes and lymphocytes, become abnormally overactive and trigger widespread inflammation. Activated histiocytes engulf other blood cells in a process called hemophagocytosis, contributing to low blood counts, and organs such as the liver, spleen, and bone marrow can become involved.
The condition arises in two general forms. A primary or familial form results from an inherited genetic change affecting how immune cells regulate their own activity, and typically appears in infancy or early childhood, while a secondary form develops later in life, triggered by an infection, cancer, or autoimmune disease that sets off the same excessive immune response.
Because the underlying immune overactivation affects multiple organ systems at once, hemophagocytic lymphohistiocytosis commonly presents with persistent fever, an enlarged liver and spleen, low blood counts, and abnormal blood clotting, and prompt recognition is important given how quickly the condition can progress.
Also known as
Used in a sentence
The patient's persistent fever, enlarged spleen, and falling blood counts prompted evaluation for hemophagocytic lymphohistiocytosis.
Good to know
Hemophagocytic lymphohistiocytosis can resemble severe sepsis or another systemic infection at first presentation, since persistent fever and organ involvement overlap with several other serious illnesses, which is part of what makes early recognition difficult.
Word origin
Where “hemophagocytic lymphohistiocytosis” comes from
Formed from Greek haima, meaning blood, and phagein, meaning to eat, describing the engulfing of blood cells, combined with lympho-, referring to lymphocytes, and histio-, from Greek histos, meaning tissue, with the suffix -osis, denoting a condition.