Hemophagocytic Lymphohistiocytosis as a Manifestation of Underlying Visceral Leishmaniasis.

Hemophagocytic lymphohistiocytosis (HLH), or hemophagocytic syndrome (HS) is a severe syndrome involving an extreme participation of the immune system, resulting in a cascade of cytokines, hyperinflammation and extensive hemophagocytosis in the bone marrow (BM) and affecting the peripheral blood (PB) lineages. Fever, splenomegaly, hypertriglyceridemia, hypofibrinogenemia, and hyperferritinemia are often encountered in this disease. The syndrome can be seen in all ages and it is either primary due to genetic defects or secondary because of malignancies, immune deficiencies, rheumatic diseases, and infections. Bacteria, viruses, protozoa, and fungi are often implicated. Visceral leishmaniasis (VL) is among the infectious causes of HLH. We describe a patient with a successful treatment of HLH after the initiation of liposomal amphotericin B, due to VL, even though there was a delay in diagnosing the leishmaniasis. The exact precipitating pathophysiological events triggering HLH remain unknown and provide their clear impact for future research. An instructive, critical review of the literature related to the presented case is provided. Distinguishing secondary HS from primary HS is essential for the application of suitable treatment. Improper use of corticosteroids could cover up an underlying possible malignancy or infection and delay the initiation of the etiologic therapeutic strategy.