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The diagnostic challenge of acute Q fever endocarditis
  1. Torcato Moreira Marques1,2,
  2. Lourenço Cruz1,
  3. Raquel Soares1 and
  4. Sofia Eusébio1
  1. 1Internal Medicine Department, Hospital de Santa Marta - Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
  2. 2NOVA Medical School, Faculdade de Ciências Médicas da Universidade NOVA de Lisboa, Lisboa, Portugal
  1. Correspondence to Dr Torcato Moreira Marques; torcato.marques{at}


A 79-year-old man was admitted to our ward with symptomatic heart failure 2 months after aortic valve replacement due to severe aortic stenosis. On the third day following admission, he became febrile (>38°C) while manifesting an increase in inflammatory markers. Endocarditis was suspected despite negative blood cultures. Echocardiogram (transthoracic and transesophageal) did not describe any vegetations. No hypermetabolic lesions were described on the Positron emission tomography scan. Empirical antibiotics were started but the fever persisted. Serologies revealed a Coxiella burnetii IgG phase II titre of 1:800, high erythrocyte sedimentation rate. Positive antinuclear antibodies, antibeta2 IgM and anticardiolipin supported a diagnosis of acute Q fever endocarditis. Doxycycline and hydroxychloroquine were started with total resolution of symptoms. This case illustrates the difficulty of diagnosing Q fever endocarditis during its acute phase, not only because vegetations can be minimal or absent, a challenge that is further compounded by a complex presentation of immunological markers.

  • infectious diseases
  • valvar diseases
  • cardiovascular medicine

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  • Contributors TMM was the junior doctor responsible for the patient, reviewed the literature and wrote the manuscript. LC was also responsible for the patient and helped reviewing the literature. RS and SE helped with the manuscript draft.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.