Pediatric Hemophagocytic Lymphohistiocytosis Presenting as a Refractory Febrile Illness: A CASE REPORT

Background Hemophagocytic Lymphohistiocytosis (HLH) is a life-threatening, exceedingly rare hyperinflammatory syndrome that typically presents with nonspecific symptoms such as fever and cytopenias. An early diagnosis of HLH is a significant clinical challenge, especially in children with presentations mimicking common infectious diseases. Case presentation A 9-year-old Pakistani girl came with a 2-week history of intractable high-grade fever, cough, and generalised weakness, unresponsive to broad-spectrum antibiotics. Physical examination showed hepatosplenomegaly and pallor. Laboratory tests showed pancytopenia, significantly elevated serum ferritin (1144 ng/ml), hypertriglyceridemia (349 mg/dL), and hypofibrinogenemia (107 mg/dL). Imaging showed hepatosplenomegaly and mild brain atrophic changes. Despite treatment with multiple antimicrobial therapies, the fever persisted, and thus, suspicion of HLH arose. She met five out of eight HLH-2004 diagnostic criteria, and on this basis, a presumptive diagnosis was established. Treatment consisted of supportive care, antipyretics, transfusions, and continued observation. Conclusion This case underscores the need to keep HLH in mind in children with chronic, treatment-resistant febrile illness, particularly in the setting of cytopenias and organomegaly. Early diagnosis and application of well-established diagnostic criteria are crucial to intervene early and enhance prognosis.