Service de Médicine Interne, INSERM U387, Hôpital Sainte-Marguerite, Marseille, France.
Jarisch-Herxheimer reaction (J-HR) is an acute febrile reaction which may complicate the initiation of an effective treatment against infections due to intracellular micro-organisms. We report a case of J-HR complicating treatment of chronic Q fever endocarditis with demonstration of elevated serum cytokine concentrations.