[Bone marrow granulomatosis in Q-fever].

Background: Petersdorf and Beeson defined Fever of Unknown Origin (FUO) as an illness characterized by rectal temperature exceeding 38.3 degrees C on at least 3 occasions, evolving during at least 3 weeks, with no diagnosis reached after 1 week of in-patient investigation. A quarter of FUO cases is caused by infectious diseases, most often hidden abscesses, subacute endocarditis and tuberculosis.

Case Report: In a 29-year-old patient with undulating fever of 3 months duration solely the demonstration of bone marrow fibrin ring granulomas led to the diagnosis of protracted Q-fever. The diagnosis later has been proved by elevated Coxiella burnetii antibody titers.

Conclusion: The case report underlines the diagnostic value of bone marrow biopsy in the evaluation of fever of unknown origin.