Systemic Bartonella henselae Infection in Immunocompetent Adult Presenting as Fever of Unknown Origin.

Systemic clinical presentations of infection caused by Bartonella henselae are rare in immunocompetent adults. We report four cases with hepatic and/or splenic involvement, presenting as fever of unknown origin. We discuss diagnosis and treatment of this infection. Bartonella henselae serology allows an easy diagnosis of hepatosplenic involvement in cat scratch disease, a clinical picture that appears to be underrecognized.