Clinical criteria for the diagnosis of HLH, proposed by the Histiocyte Society, include clinical, laboratory, and histopathologic features ( Table ). Fever and splenomegaly are the most common clinical signs, but hepatomegaly, lymphadenopathy, jaundice, and rash are also seen. The rash is commonly described as maculopapular, but nodular eruptions have also been described. Of central nervous system manifestations, encephalopathy, meningismus, and seizures are the most commonly reported[23,24]. These clinical findings may suggest an acute viral infection, such as Epstein-Barr virus (EBV), cytomegalovirus (CMV) infection, viral hepatitis, or acute HIV seroconversion, a situation complicated by the association of these infections with HLH.
The most prominent laboratory abnormalities noted are cytopenias, which may be profound. Serum chemistry findings may suggest hemolysis, with hyperbilirubinemia and elevation of lactate dehydrogenase. Most patients have hypertriglyceridemia and marked elevation of ferritin[25,26]. Serum fibrinogen is typically low, and there may be disseminated intravascular coagulation. Elevated circulating fibrin degradation products and serum ferritin in patients with HLH appear to be associated with increased risk for death.
Histopathologically, hemophagocytosis is seen in bone marrow, spleen, and lymph nodes (1,28) and occasionally the central nervous system[23,29] and skin. Activated macrophages may engulf erythrocytes, leukocytes, and platelets, their precursors, and cellular fragments. These cells appear "stuffed" with other blood cells. Hemophagocytosis may be present in the liver, but infiltration of the hepatic portal tracts with lymphocytes is also common[1,28].
Emerging Infectious Diseases. 2000;6(6) © 2000 Centers for Disease Control and Prevention (CDC)
Cite this: Hemophagocytic Syndromes and Infection - Medscape - Nov 01, 2000.