Report of a Fatal Case of Hemophagocytic Lymphohistiocytosis Syndrome and a Review of the Literature.

Hemophagocytic lymphohistiocytosis (HLH) is a rare condition in children, with a high mortality rate of 41.99%. Often, due to the atypical presentation of HLH, the syndrome is difficult to diagnose. We report a case of an atypical presentation of HLH and the diagnostic dilemma that we faced. An 11-year-old boy was hospitalized with recurrent fever, hepatosplenomegaly, and worsening jaundice. Initial laboratory workup revealed an elevated prothrombin time (PT), high bilirubin, increased alanine transaminase (ALT), and positive Epstein Barr virus (EBV) deoxyribonucleic acid (DNA) polymerase chain reaction (PCR) and EBV immunoglobulin G (IgG). Based on our patient's presentation and initial laboratory findings, further extensive workup was done, which revealed cytopenias, hypofibrinogenemia, hemophagocytosis on biopsy, absent natural killer (NK) cell activity, high serum ferritin level, and high soluble CD25 (sIL-2 receptor); a diagnosis of HLH was made. He was started on broad-spectrum antibiotics, antivirals, antifungals, and cyclosporine. He became hypoxic and hypotensive and hence was intubated and started on vasopressors. However, his coagulation profile continued to deteriorate. He started bleeding from multiple sites and became unresponsive to ventilatory support, eventually dying as a result of complications of HLH. The ambiguous clinical presentation makes the diagnosis of this syndrome difficult. However, due to the high fatality rate, early recognition and prompt treatment are of utmost importance.