Clinical Features and Complications of Coxiella burnetii Infections From the French National Reference Center for Q Fever.

in JAMA network open by Cléa Melenotte, Camélia Protopopescu, Matthieu Million, Sophie Edouard, M Patrizia Carrieri, Carole Eldin, Emmanouil Angelakis, Félix Djossou, Nathalie Bardin, Pierre-Edouard Fournier, Jean-Louis Mège, Didier Raoult

TLDR

  • A prospective cohort study of Q fever patients identified risk factors for mortality and lymphoma, highlighting the importance of routine screening for valvular heart disease and vascular anomalies, and the potential role of anticardiolipin antibodies in preventing complications.

Abstract

Q fever remains widespread throughout the world; the disease is serious and causes outbreaks and deaths when complications are not detected. The diagnosis of Q fever requires the demonstration of the presence of Coxiella burnetii and the identification of an organic lesion. To describe the hitherto neglected clinical characteristics of Q fever and identifying risk factors for complications and death. This prospective cohort study conducted from January 1, 1991, through December 31, 2016, included patients treated at the French National Reference Center for Q fever with serologic findings positive for C burnetii and clinical data consistent with C burnetii infection. Clinical data were prospectively collected by telephone. Patients with unavailable clinical data or an unidentified infectious focus were excluded. Q fever complications and mortality. Of the 180 483 patients undergoing testing, 2918 had positive findings for C burnetii and 2434 (68.8% men) presented with clinical data consistent with a C burnetii infection. Mean (SD) age was 51.8 (17.4) years, and the ratio of men to women was 2.2. At the time of inclusion, 1806 patients presented with acute Q fever, including 138 with acute Q fever that progressed to persistent C burnetii infection, and 766 had persistent focalized C burnetii infection. Rare and hitherto neglected foci of infections included lymphadenitis (97 [4.0%]), acute Q fever endocarditis (50 [2.1%]), hemophagocytic syndrome (9 [0.4%]), and alithiasic cholecystitis (11 [0.4%]). Vascular infection (hazard ratio [HR], 3.1; 95% CI, 1.7-5.7; P < .001) and endocarditis (HR, 2.4; 95% CI, 1.1-5.1; P = .02) were associated with an increased risk of death. Independent indicators of lymphoma were lymphadenitis (HR, 77.4; 95% CI, 21.2-281.8; P < .001) and hemophagocytic syndrome (HR, 19.1; 95% CI, 3.4-108.6; P < .001). The presence of anticardiolipin antibodies during acute Q fever has been associated with several complications, including hepatitis, cholecystitis, endocarditis, thrombosis, hemophagocytic syndrome, meningitis, and progression to persistent endocarditis. Previously neglected foci of C burnetii infection include the lymphatic system (ie, bone marrow, lymphadenitis) with a risk of lymphoma. Cardiovascular infections were the main fatal complications, highlighting the importance of routine screening for valvular heart disease and vascular anomalies during acute Q fever. Routine screening for anticardiolopin antibodies during acute Q fever can help prevent complications. Positron emission tomographic scanning could be proposed for all patients with suspected persistent focused infection to rapidly diagnose vascular and lymphatic infections associated with death and lymphoma, respectively.

Overview

  • The study aimed to describe the clinical characteristics of Q fever and identify risk factors for complications and death.
  • The study included patients treated at the French National Reference Center for Q fever with serologic findings positive for Coxiella burnetii and clinical data consistent with C burnetii infection.
  • The study aimed to identify neglected foci of infections and associated risk factors for mortality and lymphoma, and to explore the role of anticardiolipin antibodies in Q fever.

Comparative Analysis & Findings

  • The study found that vascular infection and endocarditis were associated with an increased risk of death.
  • Lymphadenitis and hemophagocytic syndrome were independent indicators of lymphoma.
  • The presence of anticardiolipin antibodies during acute Q fever was associated with several complications, including hepatitis, cholecystitis, endocarditis, thrombosis, hemophagocytic syndrome, meningitis, and progression to persistent endocarditis.

Implications and Future Directions

  • The study highlights the importance of routine screening for valvular heart disease and vascular anomalies during acute Q fever.
  • Routine screening for anticardiolipin antibodies during acute Q fever can help prevent complications.
  • Positron emission tomographic scanning could be proposed for all patients with suspected persistent focused infection to rapidly diagnose vascular and lymphatic infections associated with death and lymphoma, respectively.
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