Q fever endocarditis: a report of 2 cases.

Two patients with Q fever endocarditis are described. Both patients demonstrated some of the characteristic features of Q fever endocarditis, i.e. the long course of the disease before diagnosis, persistently negative blood cultures, resistance to conventional antibiotic therapy and a dramatic response to tetracycline therapy. Complications included arteriovenous thrombo-embolism and hepatic enlargement, and 1 patient developed an immune complex form of glomerulonephritis. The possibility of Q fever endocarditis should be considered in all patients with infective endocarditis in whom blood cultures are negative and who fail to respond to conventional antibiotic therapy.