Delayed diagnosis of Q fever endocarditis in a rheumatoid arthritis patient

Abstract

Chronic Q fever caused by Coxiella burnetii is uncommon in the United States and is most often associated with infective endocarditis. We present a 52-year-old woman with a history of aortic valve replacement and rheumatoid arthritis treated with Etanercept with chronic Q fever manifesting as prosthetic valve infective endocarditis. Explanted valve tissue showed organisms confirmed to be C. burnetii by PCR (polymerase chain reaction) sequencing. She subsequently reported consumption of unpasteurized cow milk which was the likely source of C. burnetii. She continues to do well 6 months after valve replacement on oral doxycycline and hydroxychloroquine.

Keywords: Coxiella burnetii endocarditis; Endocarditis and Etanercept; Q fever endocarditis; Unpasteurized milk infection.

Fig. 1

Histology of the aortic valve. (A) High power magnification of the hematoxylin-eosin stained section showed basophilic material within degenerated macrophages in a fibrinous background (original magnification 600×). (B) Small coccobacillary forms, mostly following the contours of macrophages consistent with intracellular localization and highly suggestive of bacterial organisms, were observed in the Gomori methenamine silver stain (original magnification 600×).