Acute Hemophagocytic Lymphohistiocytosis Due to Tularemia.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder marked by excessive immune system activation. Diagnosing HLH is particularly difficult due to its diverse etiology and similar clinical presentation. Patients with HLH often require intensive critical care. The condition is divided into HLH syndrome (genetic defects) and HLH disease, and both can be triggered by factors such as infections, autoimmune diseases, or malignancies. We present here the first documented case of acute HLH secondary to tularemia with septic shock in a 62-year-old female. Initially suspected due to malignancy-induced acute HLH, she was treated with etoposide and dexamethasone and was immediately transitioned to antimicrobials once she was confirmed positive for Francisella tularemia on blood cultures at the state microbiology laboratory. She had a prolonged clinical course of 31 days, followed by an excellent recovery after treatment with antimicrobials. This case highlights the importance of recognizing tularemia as a potential cause of HLH. Identifying and addressing the causative agent promptly is crucial for effective management and treatment of HLH.