Bartonella henselae infection inducing hemophagocytic lymphohistiocytosis in a kidney transplant recipient

Bartonella henselae (Bh) is the cause of cat-scratch fever. When infection is symptomatic, it typically presents with singular lymphadenitis and fever. Less commonly, the infection can become disseminated and cause endocarditis, osteomyelitis, and micro-abscesses in multiple sites including liver, spleen, eyes, and brain, especially in immunocompromised patients. Hemophagocytic lymphohistiocytosis (Hlh) is a rare and severe multisystem disorder that may be triggered by infections. In one prior case, Bh, like other infections, has induced Hlh, an immune-mediated disease that can be characterized by septic-like presentation with persistent fevers, hepatosplenomegaly, and pancytopenia. In an immunocompromised transplant recipient, the onset of Hlh can be difficult to discern from a severe presentation of Bh. We report a case of criteria-proven secondary Hlh occurring after Bh infection in an 11-yr-old girl who was 13 months post-renal transplant. The patient developed multi-organ failure, and her severe clinical presentation required a thorough evaluation for infectious and non-infectious possibilities including post-transplant lymphoproliferative disorder and rejection. Early recognition of Hlh allowed for better directed therapies, leading to recovery of the patient and resolution of both Bh and Hlh.