Hepatitis b-a rare cause of hemophagocytic lymphohistiocytosis

ABSTRACT

INTRODUCTION: Acquired Hemophagocytic lymphohistiocytosis (HLH) is rare with an incidence of 1.2 per 1,000,000 individuals. It can be caused by infection, malignancy, autoimmune disorders or can be idiopathic. To our knowledge, we present the third case of a patient clinically diagnosed with HLH associated with isolated Hepatitis B. CASE DESCRIPTION/METHODS: A 49 year-old-male from Tajikistan with no past medical history presented with persistent fevers for 3 months associated with non-productive cough, unintentional weight loss and night sweats. Vitals were stable and physical exam was remarkable for pallor and hepatosplenomegaly. Labs Hgb 7.8 g/dl, PLT 133 mcl, WBC 2.68 mcl, Ferritin 2717ng/ml, Triglycerides 421mg/dl. His pancytopenia was suggestive of an underlying hematological malignancy, and a bone marrow biopsy was performed;it was non-diagnostic, with minimal evidence of RBC phagocytosis. Extensive work up was obtained and negative (Figure 1). Serum soluble IL-2 level was elevated, 10972 units/mL. The patient was diagnosed with HLH secondary to chronic hepatitis B infection and treated with high dose dexamethasone, Etoposide and Tenofovir with significant improvement. DISCUSSION: HLH is a fatal, rare condition characterized by fever, hyperferritinemia, hepatosplenomegaly, hepatic dysfunction, and uncontrolled hemophagocytosis throughout the reticuloendothelial system caused by immune hyperactivation and hypercytokinemia. Acquired HLH is usually associated with malignancy, viral infection, autoimmune disorder, or can be idiopathic. Lymphoma is the most common malignancy to cause acquired HLH and Epstein-Barr virus the most common infection. Isolated Hepatitis B is an extremely rare cause of HLH, with 2 other cases reported. Despite having a non-diagnostic bone marrow biopsy, he met multiple diagnostic criteria for HLH;fever >7 days, splenomegaly, cytopenia involving >2 cell lines, hyperferritinemia, and elevated soluble interleukin-2. He was treated with Tenofovir, high-dose dexamethasone and Etoposide in order to prevent reactivation of Hepatitis B. This case highlights the urgency to establish the cause of HLH, with Hepatitis being a differential, as initiating chemotherapy without treating his Hepatitis B may have led to unwanted complications including delay in chemotherapy, hepatic failure, and death. HLH caused by isolated Hepatitis B is rare and this case serves to increase awareness of diagnosis and management, especially since there is now reported association with SARS-CoV-2 and HLH.