Infection-associated hemophagocytic syndromes (IAHS) refer to a group of rare and serious medical conditions characterized by an overactive immune response to an infection. These syndromes are also known as secondary hemophagocytic lymphohistiocytosis (sHLH) or macrophage activation syndrome (MAS).
Hemophagocytic syndromes occur when the immune system becomes overactivated, leading to excessive production and release of cytokines (small proteins involved in immune responses). This results in uncontrolled inflammation and widespread tissue damage throughout the body.
IAHS specifically refers to cases where the underlying trigger for the immune system dysfunction is an infection. Various infectious agents, including viruses (such as Epstein-Barr, dengue, or influenza), bacteria (such as tuberculosis or staphylococcus), and fungi (such as histoplasma or candida), can initiate IAHS.
The symptoms of IAHS may include fever, enlarged liver and spleen, cytopenias (reduced blood cell counts), abnormal blood clotting, jaundice, and organ dysfunction. Laboratory tests often reveal abnormalities such as low platelet and white blood cell counts, high ferritin levels, and evidence of hemophagocytosis (the ingestion of blood cells by immune cells).
Prompt diagnosis and treatment are crucial for IAHS, as the condition can rapidly progress and become life-threatening. Treatment typically involves addressing the underlying infection and administrating immunosuppressive medications to control the immune response. Additional supportive measures like blood transfusions and organ support may also be necessary.
In summary, IAHS refers to a group of rare syndromes in which the immune system reacts excessively to an infection, leading to uncontrolled inflammation and tissue damage throughout the body.
