Hemophagocytic Lymphohistiocytosis in Children: Clinical Profile and Outcome.

Objectives: The objectives of this study were to describe the clinical and etiologic profile and outcomes of children with hemophagocytic lymphohistiocytosis (HLH) in a tertiary care hospital in South India.
Methods: This is a combined 2-year prospective (2017 to 2018) and 5-year retrospective (2012 to 2016) descriptive study in which children from birth to 18 years who satisfied the HLH-2004 diagnostic criteria were included. Case details from patient records were analyzed.
Results: Fifty-three cases were enrolled of which 20 were prospective and 33 were retrospective. Fever, hepatomegaly, anemia, and hyperferritinemia were the common presentations. Infectious triggers were found in 33 (62%) cases. Five cases were secondary to rheumatic diseases, and 8 were primary HLH. Bacterial (14 cases) followed by viral infections (10 cases) were the leading triggers. Scrub typhus (6 cases) and dengue (4 cases) were the most common infectious agents. Major complications include febrile neutropenia (38%) and multiorgan dysfunction (26%). One child developed secondary malignancy. The most frequently used immunosuppressive drug for the treatment of HLH was steroid (70%), while 28% of cases recovered with only supportive therapy. The overall mortality was 41%.
Conclusions: Infections were the most common triggers for HLH of which tropical infectious agents constituted the majority. Treatment with steroids alone or regimens without cytotoxic drugs may result in resolution of secondary HLH with mild to moderate disease activity. Without stem cell transplant, primary HLH has a high mortality rate.