Hemophagocytic lymphohistiocytosis syndrome in Dengue hemorrhagic fever.

Hemophagocytic lymphohistiocytosis (HLH) is a life threatening florid activation of macrophages of the lymphoreticular system. It is reported to be associated with dengue in children in India and carries a high mortality. Patients present with high fever, worsening blood cell counts, splenomegaly, abnormal liver enzymes with features of liver failure, coagulopathy and neurological complications. The diagnosis is according to "Diagnostic Guidelines for HLH 2004", based on a triad of clinical, blood parameters and bone marrow cytology. In the present study, data of 212 children admitted with dengue were analyzed. Of 212 children, 31 children were classified as suspect HLH and advised bone marrow evaluation; of whom 23 children had marrow evidence of HLH. Worsening of blood cell counts were recorded in all children with a mean platelet count of 58,303.03 cells/cumm, low hematocrit in 95.65 %, low mean hemoglobin level of 8.37 g/dL, high erythrocyte sedimentation rate (ESR) and prolonged pro-thrombin time/international normalization ratio (PT/INR). Serum triglycerides, ferritin and transaminases were high. Of the 23 children, 19 patients received intravenous immunoglobulin (IVIG) and all of these children recovered. Dengue with multi-organ dysfunction is commonly concurrent to HLH in the marrow and hence, an early diagnosis based on clinical, laboratory and bone marrow evaluation is significant. A bone marrow evaluation confirms the diagnosis of HLH.