Splenic Cat-Scratch Disease in a Patient Receiving Etanercept: A Case Report and Review of Diagnosis, Management, and Risk of Persistent Imaging Findings

Abstract

Abstract: Cat-scratch disease (CSD), caused by Bartonella henselae, is most often a self-limited regional lymphadenopathy in immunocompetent hosts but can present with atypical, disseminated manifestations in immunosuppressed patients. We describe a 66-year-old woman with rheumatoid arthritis on etanercept who presented with a subacute febrile illness, severe hyponatremia, splenomegaly with multifocal splenic lesions, and laboratory features mimicking secondary hemophagocytic lymphohistiocytosis. Initial bone marrow and computed tomography (CT)-guided splenic biopsies were nondiagnostic, and an extensive infectious workup was unrevealing. After an exposure history identified close contact with outdoor cats, add-on broad-range polymerase chain reaction (PCR) on the previously obtained splenic tissue confirmed Bartonella species. She was treated with doxycycline and rifampin, etanercept was discontinued, and she had complete clinical recovery despite persistent sub-centimeter splenic lesions on follow-up imaging. This case highlights splenic cat-scratch disease as an important consideration in febrile patients on TNF-α inhibitor therapy with multifocal splenic lesions, the diagnostic value of broad-range tissue PCR, and the interpretation of residual radiographic findings after treatment.