Acute Q fever and the risk of developing endocarditis

Objectives: Assess clinical and serological data as parameters indicative of a possible evolution to endocarditis after an episode of acute Q fever.

Patients and methods: Retrospective cohort study of evolution to endocarditis after an acute Q fever episode, analyzing the clinical and serological evolution and the antibiotic treatment administered.

Results: Eighty patients were recruited, 20% of whom had phase i IgG antibody levels ≥ 1:1024 in the first 3 months. Only 44% of the patients underwent antibiotherapy in the acute phase; only 2 patients underwent extended antibiotherapy. Fifteen percent of the patients underwent an echocardiogram. None of the patients had symptoms suggestive of chronic infection or progressed to endocarditis after a median follow-up of 100 months, regardless of the early increase in phase i IgG antibodies.

Conclusions: The early increase in phase i IgG antibodies in asymptomatic patients is not associated with progression to endocarditis despite not undergoing prolonged antibiotic treatment.