Ajay Chauhan, Kapil Sharma, Aparna Valsan, Prajwal Gowda, Sumita Sharma
Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome. It can closely mimic severe sepsis and multiorgan dysfunction. Intravesical bacillus Calmette-Guérin (BCG), used for non-muscle invasive bladder cancer, is rarely associated with systemic infection or immune-mediated complications. We report a 50-year-old man who developed high-grade fever and progressive jaundice shortly after intravesical BCG therapy. He had hepatosplenomegaly, pancytopenia, hepatitis, coagulopathy, acute kidney injury, marked hyperferritinemia, hypofibrinogenemia, and hypertriglyceridemia. Urine polymerase chain reaction detected Mycobacterium bovis. Bone marrow examination revealed hemophagocytosis. He fulfilled six HLH-2004 criteria and had an HScore of 299, indicating a very high probability of HLH. After starting injection dexamethasone, there was transient clinical and biochemical improvement, but he deteriorated, and despite escalation to etoposide, he died on Day 19. This case highlights BCG-associated secondary HLH as a sepsis mimic and emphasizes the need for early ferritin testing, HLH scoring, and targeted mycobacterial evaluation in post-BCG patients with persistent fever, cytopenias, hepatitis, and organ dysfunction.