Hemophagocytic Lymphohistiocytosis in a Critically Ill Patient: A Case Report of a Potentially Fatal Entity.

Background: Hemophagocytic lymphohistiocytosis (HLH) is a non-neoplastic proliferation and macrophage activation that induces cytokine-mediated bone marrow suppression and features of intense phagocytosis in the bone marrow and liver, leading to multi-organ dysfunction and ultimate failure. The diagnosis of HLH in an intensive care setting is challenging, and it is associated with high morbidity and mortality. HLH-94 is the standard protocol for treatment, consisting of dexamethasone and chemotherapy like etoposide.

Case presentation: We present the case of a 73-year-old woman who had a prolonged hospitalization for vomiting, diarrhea, and dehydration. Her conditions were complicated by acute refractory pancytopenia on the 12th day of admission, leading to multi-organ failure, including anuric renal failure requiring renal replacement therapy and respiratory failure requiring intubation. After a thorough workup, she was diagnosed with HLH using HLH-2004 diagnostic criteria and confirmed by a bone marrow biopsy. She was started on supportive therapy and high-dose intravenous dexamethasone with an appropriate clinical response. Her pancytopenia improved, and she no longer required ventilator support for respiratory failure or dialysis for renal failure. Unfortunately, her hospital course was complicated by a sentinel event leading to her death.

Conclusion: This case emphasizes that early recognition and treatment initiation of HLH are crucial to prevent adverse outcomes and mortality. Treatment should be tailored based on the underlying HLH trigger, as chemotherapy-based treatment regimens may result in overtreatment and unnecessary toxicities. Further studies are needed to increase clinicians' awareness and management of secondary cases of HLH.