Hemophagocytic Lymphohistiocytosis mimics many common conditions: case series and review of literature.

Introduction. Hemophagocytic lymphohistiocytosis (HLH), a rare but potentially fatal disease, is characterized by excessive immune activation and cytokine release which stimulates bone marrow macrophages to engulf hematopoietic cells. HLH could be secondary to infections: viral, fungal, and bacterial; malignancies and autoimmune diseases. The diagnosis of HLH is usually delayed due to the presence of non-specific symptoms at presentation. This delay contributes to increased mortality. Cases and review. We present the case of 4 patients who presented with subjective fevers and extreme fatigue. Patients all had systemic inflammatory response syndrome (SIRS). All patients were initially managed as in sepsis from an underlying infection. All unfortunately progressed to multiple organs dysfunction and died. The underlying causes for HLH in the patients were considered to be: HIV/AIDS, T cell lymphoma, histoplasmosis and juvenile rheumatoid arthritis. We have also included a brief review of the literature on HLH highlighting the treatment and outcomes of patients in case series; and the many conditions which can trigger HLH. Conclusion. Patients with HLH usually share various non-specific symptoms, such as fever and malaise, with patients across a wide spectrum of conditions: from bacterial sepsis to malignancies. Since early suspicion and diagnosis is critical to prompt therapy and improved mortality, including HLH as a possible cause of fever particularly in patients with prolonged fever of unknown origin and cytopenias will be crucial.